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1
MATHUSA, EMILY C., YUHUAN CHEN, ELENA ENACHE y LLOYD HONTZ. "Non-O157 Shiga Toxin–Producing Escherichia coli in Foods". Journal of Food Protection 73, n.º 9 (1 de septiembre de 2010): 1721–36. http://dx.doi.org/10.4315/0362-028x-73.9.1721.
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Non-O157 Shiga toxin–producing Escherichia coli (STEC) strains have been linked to outbreaks and sporadic cases of illness worldwide. Illnesses linked to STEC serotypes other than O157:H7 appear to be on the rise in the United States and worldwide, indicating that some of these organisms may be emerging pathogens. As more laboratories are testing for these organisms in clinical samples, more cases are uncovered. Some cases of non-O157 STEC illness appear to be as severe as cases associated with O157, although in general cases attributed to non-O157 are less severe. There is much variation in virulence potential within STEC serotypes, and many may not be pathogenic. Of more than 400 serotypes isolated, fewer than 10 serotypes cause the majority of STEC-related human illnesses. Various virulence factors are involved in non-O157 STEC pathogenicity; the combined presence of both eae and stx genes has been associated with enhanced virulence. A scientific definition of a pathogenic STEC has not yet been accepted. Several laboratories have attempted to develop detection and identification methods, and although substantial progress has been made, a practical method of STEC detection has yet to be validated. Worldwide, foods associated with non-O157 STEC illness include sausage, ice cream, milk, and lettuce, among others. Results from several studies suggest that control measures for O157 may be effective for non-O157 STEC. More research is needed to uncover unique characteristics and resistances of non-O157 STEC strains if they exist. The public health significance of non-O157 STEC and the implications for industry practices and regulatory actions are discussed.
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Paquette, Sarah-Jo, Rahat Zaheer, Kim Stanford, James Thomas y Tim Reuter. "Competition among Escherichia coli Strains for Space and Resources". Veterinary Sciences 5, n.º 4 (2 de noviembre de 2018): 93. http://dx.doi.org/10.3390/vetsci5040093.
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Shiga toxin-producing Escherichia coli (STEC) are a subgroup of E. coli causing human diseases. Methods to control STEC in livestock and humans are limited. These and other emerging pathogens are a global concern and novel mitigation strategies are required. Habitats populated by bacteria are subjected to competition pressures due to limited space and resources but they use various strategies to compete in natural environments. Our objective was to evaluate non-pathogenic E. coli strains isolated from cattle feces for their ability to out-compete STEC. Competitive fitness of non-pathogenic E. coli against STEC were assessed in competitions using liquid, agar, and nutrient limiting assays. Winners were determined by enumeration using O-serogroup specific quantitative PCR or a semi-quantitative grading. Initial liquid competitions identified two strong non-pathogenic competitors (O103F and O26E) capable of eliminating various STEC including O157 and O111. The strain O103F was dominant across permeable physical barriers for all tested E. coli and STEC strains indicating the diffusion of antimicrobial molecules. In direct contact and even with temporal disadvantages, O103F out-competed STEC O157E. The results suggest that O103F or the diffusible molecule(s) it produces have a potential to be used as an alternative STEC mitigation strategy, either in medicine or the food industry.
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SMITH, JAMES L. y PINA M. FRATAMICO. "Effect of Stress on Non-O157 Shiga Toxin–Producing Escherichia coli†". Journal of Food Protection 75, n.º 12 (1 de diciembre de 2012): 2241–50. http://dx.doi.org/10.4315/0362-028x.jfp-12-255.
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Non-O157 Shiga toxin–producing Escherichia coli (non-O157 STEC) strains have emerged as important foodborne pathogens worldwide. Non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 have been declared as adulterants in beef by the U.S. Department of Agriculture Food Safety and Inspection Service. While documentation is limited, treatments including heat and acid that have been shown to inactivate E. coli O157:H7 will likely also destroy non-O157 STEC; however, non-O157 STEC strains show variability in their responses to stress. It has been shown that non-O157 STEC may survive in fermented sausages and cheeses, and treatments such as high pressure may be necessary to eliminate non-O157 STEC from these products. The mechanisms used by non-O157 STEC to resist acid environments are similar to those used by O157:H7 strains and include the acid tolerance response, the oxidative system, and the glutamate and arginine decarboxylase systems. However, one study demonstrated that some non-O157 STEC strains utilize a chaperone-based acid stress response (HdeA and HdeB) to combat acidic conditions, which is lacking in E. coli O157:H7. Genomic studies suggest that while non-O157 STEC can cause diseases similar to those caused by E. coli O157:H7, O157 and non-O157 STECs have different evolutionary histories. Non-O157 STECs are a heterogeneous group of organisms, and there is currently a limited amount of information on their virulence, fitness, and stress responses, rendering it difficult to draw firm conclusions on their behavior when exposed to stress in the environment, in food, and during processing.
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HUSSEIN, HUSSEIN S. y LAURIE M. BOLLINGER. "Prevalence of Shiga Toxin–Producing Escherichia coli in Beef Cattle". Journal of Food Protection 68, n.º 10 (1 de octubre de 2005): 2224–41. http://dx.doi.org/10.4315/0362-028x-68.10.2224.
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A large number of Shiga toxin–producing Escherichia coli (STEC) strains have caused major outbreaks and sporadic cases of human illnesses, including mild diarrhea, bloody diarrhea, hemorrhagic colitis, and the life-threatening hemolytic uremic syndrome. These illnesses have been traced to both O157 and non-O157 STEC. In a large number of STEC-associated outbreaks, the infections were attributed to consumption of ground beef or other beef products contaminated with cattle feces. Thus, beef cattle are considered reservoirs of STEC and can pose significant health risks to humans. The global nature of the human food supply suggests that safety concerns with beef will continue and the challenges facing the beef industry will increase at the production and processing levels. To be prepared to address these concerns and challenges, it is critical to assess the role of beef cattle in human STEC infections. In this review, published reports on STEC in beef cattle were evaluated to achieve the following specific objectives: (i) assess the prevalence of STEC in beef cattle, and (ii) determine the potential health risks of STEC strains from beef cattle. The latter objective is critically important because many beef STEC isolates are highly virulent. Global testing of beef cattle feces revealed wide ranges of prevalence rates for O157 STEC (i.e., 0.2 to 27.8%) and non-O157 STEC (i.e., 2.1 to 70.1%). Of the 261 STEC serotypes found in beef cattle, 44 cause hemolytic uremic syndrome and 37 cause other illnesses.
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KARCH, HELGE, HANS-IKO HUPPERTZ, JOCHEN BOCKEMÜHL, HERBERT SCHMIDT, ANDREAS SCHWARZKOPF y REINHARD LISSNER. "Shiga Toxin-Producing Escherichia coli Infections in Germany†". Journal of Food Protection 60, n.º 11 (1 de noviembre de 1997): 1454–57. http://dx.doi.org/10.4315/0362-028x-60.11.1454.
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A prospective study was carried out in collaboration with two children's hospitals in Würzburg, Germany to assess the incidence and clinical manifestations of infections due to Shiga toxin-producing Escherichia coli (STEC) in children. Between 1991 and 1995, stool samples from 2788 children with enteritis were investigated for the occurrence of STEC. STEC cultures from stools were screened using PCR with primers complementary to Shiga toxin 1(Stx1) and Shiga toxin 2 (Stx2) genes. PCR-positive samples were further subjected to colony blot hybridization and probe positive colonies were serotyped and analyzed for the presence of virulence genes. There was an increase in the incidence of STEC infections from 0.4% in 1991 to 2.8% in 1994. In 1995 the number of infections remained nearly unchanged (2.5%). Infection with STEC was associated with painful nonbloody diarrhea in most patients. Among the 35 patients in this study with stools containing STEC, only 9 (25.7%) had O157 colonies of which 3 (8.6%) were O157:H7 and 6 (17.1%) were sorbitol-fermenting O157:H−. In an additional study in 1994/l995, STEC etiology in 88 patients with HUS from Germany was confirmed in our laboratories by culture of STEC from stools, and in 20 additional HUS cases by serological analysis. Of the strains from stools of HUS patients, 78% belonged to serogroup O157. The most frequently isolated non-O157 serogroups were O26 and O111. These results demonstrate that when analyzing stools of patients with bloody diarrhea, HUS, or painful nonbloody diarrhea, the occurrence of non-O157:H7 strains should be considered when classical microbiological analysis fails to yield a standard enteric pathogen, such as Campylobacter. E. coli O157:H7, Salmonella. Shigella, or Yersinia.
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CERNICCHIARO, N., D. G. RENTER, C. A. CULL, Z. D. PADDOCK, X. SHI y T. G. NAGARAJA. "Fecal Shedding of Non-O157 Serogroups of Shiga Toxin–Producing Escherichia coli in Feedlot Cattle Vaccinated with an Escherichia coli O157:H7 SRP Vaccine or Fed a Lactobacillus-Based Direct-Fed Microbial†". Journal of Food Protection 77, n.º 5 (1 de mayo de 2014): 732–37. http://dx.doi.org/10.4315/0362-028x.jfp-13-358.
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The objectives of this study were to determine whether fecal shedding of non-O157 Shiga toxin–producing Escherichia coli (STEC) in feedlot cattle was affected by the use of an E. coli O157:H7 vaccine or a direct-fed microbial (DFM) and whether the shedding of a particular non-O157 STEC serogroup within feces was associated with shedding of O157 or other non-O157 STEC serogroups. A total of 17,148 cattle in 40 pens were randomized to receive one, both, or neither (control) of the two interventions: a vaccine based on the siderophore receptor and porin proteins (E. coli SRP vaccine, two doses) and a DFM product (low-dose Bovamine). Fresh fecal samples (30 samples per pen) were collected weekly from pen floors for four consecutive weeks beginning approximately 56 days after study allocation. DNA extracted from enriched samples was tested for STEC O157 and non-O157 serogroups O26, O45, O103, O111, O121, and O145 and for four major virulence genes (stx1, stx2, eae, and ehxA) using an 11-gene multiplex PCR assay. Generalized linear mixed models were used to analyze the effects of treatments and make within-sample comparisons of the presence of O-serogroup–specific genes. Results of cumulative prevalence measures indicated that O157 (14.6%), O26 (10.5%), and O103 (10.3%) were the most prevalent STEC O serogroups. However, the vaccine, DFM, or both had no significant effect (P > 0.05) on fecal prevalence of the six non-O157 STEC serogroups in feedlot cattle. Within-sample comparisons of the presence of STEC serogroup–specific genes indicated that fecal shedding of E. coli O157 in cattle was associated with an increased probability (P < 0.05) of fecal shedding of STEC O26, O45, O103, and O121. Our study revealed that neither the E. coli O157:H7 vaccine, which reduced STEC O157 fecal shedding, nor the DFM significantly affected fecal shedding of non-O157 STEC serogroups, despite the fact that the most prevalent non-O157 STEC serogroups tended to occur concurrently with O157 STEC strains within fecal samples.
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ACHESON, DAVID W. K. "How Does Escherichia coli O157:H7 Testing in Meat Compare with What We Are Seeing Clinically?" Journal of Food Protection 63, n.º 6 (1 de junio de 2000): 819–21. http://dx.doi.org/10.4315/0362-028x-63.6.819.
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Escherichia coli O157:H7 is but one of a group of Shiga toxin-producing E. coli (STEC) that cause both intestinal disease such as bloody and nonbloody diarrhea and serious complications like hemolytic uremic syndrome (HUS). While E. coli O157: H7 is the most renowned STEC, over 200 different types of STEC have been documented in meat and animals, at least 60 of which have been linked with human disease. A number of studies have suggested that non-O157 STEC are associated with clinical disease, and non-O157 STEC are present in the food supply. Non-O157 STEC, such as O111 have caused large outbreaks and HUS in the United States and other countries. The current policy in the United States is to examine ground beef for O157:H7 only, but restricting the focus to O157 will miss other important human STEC pathogens.
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TERAO, YOSHITAKA, KANA TAKESHITA, YASUTAKA NISHIYAMA, NAOKI MORISHITA, TAKASHI MATSUMOTO y FUMIKI MORIMATSU. "Promising Nucleic Acid Lateral Flow Assay Plus PCR for Shiga Toxin–Producing Escherichia coli". Journal of Food Protection 78, n.º 8 (1 de agosto de 2015): 1560–68. http://dx.doi.org/10.4315/0362-028x.jfp-14-495.
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Shiga toxin (Stx)–producing Escherichia coli (STEC) is a frequent cause of foodborne infections, and methods for rapid and reliable detection of STEC are needed. A nucleic acid lateral flow assay (NALFA) plus PCR was evaluated for detecting STEC after enrichment. When cell suspensions of 45 STEC strains, 14 non-STEC strains, and 13 non–E. coli strains were tested with the NALFA plus PCR, all of the STEC strains yielded positive results, and all of the non-STEC and non–E. coli strains yielded negative results. The lower detection limit for the STEC strains ranged from 0.1 to 1 pg of genomic DNA (about 20 to 200 CFU) per test, and the NALFA plus PCR was able to detect Stx1- and Stx2-producing E. coli strains with similar sensitivities. The ability of the NALFA plus PCR to detect STEC in enrichment cultures of radish sprouts, tomato, raw ground beef, and beef liver inoculated with 10-fold serially diluted STEC cultures was comparable to that of a real-time PCR assay (at a level of 100 to 100,000 CFU/ml in enrichment culture). The bacterial inoculation test in raw ground beef revealed that the lower detection limit of the NALFA plus PCR was also comparable to that obtained with a real-time PCR assay that followed the U.S. Department of Agriculture guidelines. Although further evaluation is required, these results suggest that the NALFA plus PCR is a specific and sensitive method for detecting STEC in a food manufacturing plant.
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ENACHE, ELENA, EMILY C. MATHUSA, PHILIP H. ELLIOTT, D. GLENN BLACK, YUHUAN CHEN, VIRGINIA N. SCOTT y DONALD W. SCHAFFNER. "Thermal Resistance Parameters for Shiga Toxin–Producing Escherichia coli in Apple Juice". Journal of Food Protection 74, n.º 8 (1 de agosto de 2011): 1231–37. http://dx.doi.org/10.4315/0362-028x.jfp-10-488.
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The purpose of the present study was to determine the heat resistance of six non-O157 Shiga toxin–producing Escherichia coli (STEC) serotypes in comparison to E. coli O157:H7 in single-strength apple juice without pulp. The thermal parameters for stationary-phase and acid-adapted cells of E. coli strains from serogroups O26, O45, O103, O111, O121, O145, and O157:H7 were determined by using an immersed coil apparatus. The most heat-sensitive serotype in the present study was O26. Stationary-phase cells for serotypes O145, O121, and O45 had the highest D56°C-value among the six non-O157 serotypes studied, although all were significantly lower (P < 0.05) than that of E. coli O157:H7. At 60°C E. coli O157:H7 and O103 demonstrated the highest D-values (1.37 ± 0.23 and 1.07 ± 0.03 min, respectively). The D62°C for the most heat-resistant strain belonging to the serotype O145 was similar (P > 0.05) to that for the most resistant O157:H7 strain (0.61 ± 0.17 and 0.60 ± 0.09 min, respectively). The heat resistance for stationary-phase cells was generally equal to or higher than that of acid-adapted counterparts. Although E. coli O157:H7 revealed D-values similar to or higher than the individual six non-O157 STEC serotypes in apple juice, the z-values for most non-O157 STEC tested strains were greater than those of E. coli O157:H7. When data were used to calculate heat resistance parameters at a temperature recommended in U.S. Food and Drug Administration guidance to industry, the D71.1°C for E. coli O157:H7 and non-O157 STEC serotypes were not significantly different (P > 0.05).
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THRAN, B. H., H. S. HUSSEIN, M. R. HALL y S. F. KHAIBOULLINA. "Shiga Toxin–Producing Escherichia coli in Beef Heifers Grazing an Irrigated Pasture". Journal of Food Protection 64, n.º 10 (1 de octubre de 2001): 1613–16. http://dx.doi.org/10.4315/0362-028x-64.10.1613.
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Shiga toxin–producing Escherichia coli (STEC) produce toxins that have been associated with several human illnesses. E. coli O157:H7 is the most well-studied STEC and was first associated with consumption of improperly cooked ground beef in 1982. E. coli O157:H7 is not the only foodborne STEC because other STEC serotypes are also associated with human illnesses. The objective of this study was to assess prevalence of STEC in 23 yearling beef (Angus) heifers grazing an irrigated grass pasture in spring (April), summer (July), fall (October), and winter (December) of 1999. A total of 86 fecal samples were rectally collected and were subjected to microbiological testing for the presence of STEC. Nine E. coli isolates from five heifers (one in spring and fall and three in winter) were toxic to Vero cells. Of these isolates, four were E. coli O157:H7, two belonged to the serogroup O6, one O39:NM, one O113:H−, and the final isolate was untypable. The STEC prevalence rate in our herd ranged from 4% (spring) to 15% (winter). Based on detecting both O157:H7 and non-O157:H7 STEC in our heifers, it is clear that screening fecal samples should not be limited to E. coli O157:H7. Identification of STEC-positive cattle prior to slaughter should help in reducing the risk of beef contamination with such foodborne pathogens if pre- and/or postharvest control measures are applied to such animals.
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KATAOKA, AI, ELENA ENACHE, MARIA SOHAIL, PHILIP H. ELLIOTT y D. GLENN BLACK. "Inactivation of Shiga Toxin–Producing Escherichia coli in Single-Strength Lemon and Lime Juices Containing Preservatives". Journal of Food Protection 74, n.º 10 (1 de octubre de 2011): 1746–50. http://dx.doi.org/10.4315/0362-028x.jfp-11-083.
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The objective of this study was to determine the inactivation of non-O157 Shiga toxin–producing Escherichia coli (STEC) serotypes in comparison with O157 STEC in commercially produced, shelf-stable lemon and lime juices. The present validation tests confirmed that storage of the juices containing preservatives at room temperatures (22°C) for 3 days (72 h) ensures a >6-log reduction of O26, O45, O103, O111, O121, O145, and O157 STEC. These results demonstrate that non-O157 STEC had survival abilities comparable to those of E. coli O157:H7 strains in acidic food products such as lemon and lime juices (pH 2.5 ± 0.1); therefore, the storage conditions deemed to inactivate E. coli O157:H7 similarly inactivate the non-O157 serotypes.
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Tack, Danielle M., Hannah M. Kisselburgh, LaTonia C. Richardson, Aimee Geissler, Patricia M. Griffin, Daniel C. Payne y Brigette L. Gleason. "Shiga Toxin-Producing Escherichia coli Outbreaks in the United States, 2010–2017". Microorganisms 9, n.º 7 (17 de julio de 2021): 1529. http://dx.doi.org/10.3390/microorganisms9071529.
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Shiga toxin-producing Escherichia coli (STEC) cause illnesses ranging from mild diarrhea to ischemic colitis and hemolytic uremic syndrome (HUS); serogroup O157 is the most common cause. We describe the epidemiology and transmission routes for U.S. STEC outbreaks during 2010–2017. Health departments reported 466 STEC outbreaks affecting 4769 persons; 459 outbreaks had a serogroup identified (330 O157, 124 non-O157, 5 both). Among these, 361 (77%) had a known transmission route: 200 foodborne (44% of O157 outbreaks, 41% of non-O157 outbreaks), 87 person-to-person (16%, 24%), 49 animal contact (11%, 9%), 20 water (4%, 5%), and 5 environmental contamination (2%, 0%). The most common food category implicated was vegetable row crops. The distribution of O157 and non-O157 outbreaks varied by age, sex, and severity. A significantly higher percentage of STEC O157 than non-O157 outbreaks were transmitted by beef (p = 0.02). STEC O157 outbreaks also had significantly higher rates of hospitalization and HUS (p < 0.001).
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LITT, PUSHPINDER KAUR, JOYJIT SAHA y DIVYA JARONI. "Characterization of Bacteriophages Targeting Non-O157 Shiga Toxigenic Escherichia coli". Journal of Food Protection 81, n.º 5 (6 de abril de 2018): 785–94. http://dx.doi.org/10.4315/0362-028x.jfp-17-460.
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ABSTRACT Non-O157 Shiga toxigenic Escherichia coli (STEC) are an important group of foodborne pathogens, implicated in several outbreaks and recalls in the past 2 decades. It is therefore crucial to devise effective control strategies against these pathogens. Bacteriophages present an attractive alternative to conventional pathogen control methods in the food industry. Bacteriophages, targeting non-O157 STEC (O26, O45, O103, O111, O121, O145), were isolated from beef cattle operations in Oklahoma. Their host range and lytic ability were determined against several (n = 21) non-O157 STEC isolates, by using the spot-on-lawn assay. Isolated phages were purified, and their morphology was determined under a transmission electron microscope. Infection kinetics of selected phages (n = 19), particularly adsorption rate, rise period, latent period, and burst size, were determined. Phages were also evaluated for stability at a wide pH range (1 to 11) and temperature range (−80 to 90°C). In total, 45 phages were isolated and classified into Myoviridae, Siphoviridae, or Tectiviridae. The phages had a latent period between 8 and 37 min, a rise period between 19 and 40 min, and a large burst size (12 to 794 virions per infected cell), indicating high lytic activity. Tested phages were stable at pH 5 to 9 for 24 h, whereas a decrease in phage titer was observed at pHs 1, 2, and 11. Phages were stable at 40 and 60°C, except for O103-specific phages. At 70°C, all the phages lost viability after 20 min, except three phages targeting O26 and O121 and one phage targeting O45 and O111 STEC, which remained viable for 60 min. All the phages lost activity after 10 min at 90°C, except one each of O26 and O121 STEC–infecting phages that remained viable for 60 min. Phages remained stable for 90 days under refrigerated (4°C) and frozen (−20 and −80°C) storage. Characterization of phages, targeting diverse non-O157 STEC serotypes, could help in the development of effective biocontrol strategies for this group of pathogens in the food industry.
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TAYLOR, E. V., T. A. NGUYEN, K. D. MACHESKY, E. KOCH, M. J. SOTIR, S. R. BOHM, J. P. FOLSTER et al. "Multistate Outbreak of Escherichia coli O145 Infections Associated with Romaine Lettuce Consumption, 2010‡§". Journal of Food Protection 76, n.º 6 (1 de junio de 2013): 939–44. http://dx.doi.org/10.4315/0362-028x.jfp-12-503.
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Non-O157 Shiga toxin–producing Escherichia coli (STEC) can cause severe illness, including hemolytic uremic syndrome (HUS). STEC O145 is the sixth most commonly reported non-O157 STEC in the United States, although outbreaks have been infrequent. In April and May 2010, we investigated a multistate outbreak of STEC O145 infection. Confirmed cases were STEC O145 infections with isolate pulsed-field gel electrophoresis patterns indistinguishable from those of the outbreak strain. Probable cases were STEC O145 infections or HUS in persons who were epidemiologically linked. Case-control studies were conducted in Michigan and Ohio; food exposures were analyzed at the restaurant, menu, and ingredient level. Environmental inspections were conducted in implicated food establishments, and food samples were collected and tested. To characterize clinical findings associated with infections, we conducted a chart review for case patients who sought medical care. We identified 27 confirmed and 4 probable cases from five states. Of these, 14 (45%) were hospitalized, 3 (10%) developed HUS, and none died. Among two case-control studies conducted, illness was significantly associated with consumption of shredded romaine lettuce in Michigan (odds ratio [OR] = undefined; 95%confidence interval [CI] = 1.6 to undefined) and Ohio (OR = 10.9; 95%CI = 3.1 to 40.5). Samples from an unopened bag of shredded romaine lettuce yielded the predominant outbreak strain. Of 15 case patients included in the chart review, 14 (93%) had diarrhea and abdominal cramps and 11 (73%) developed bloody diarrhea. This report documents the first foodborne outbreak of STEC O145 infections in the United States. Current surveillance efforts focus primarily on E. coli O157 infections; however, non-O157 STEC can cause similar disease and outbreaks, and efforts should be made to identify both O157 and non-O157 STEC infections. Providers should test all patients with bloody diarrhea for both non-O157 and O157 STEC.
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Szczerba-Turek, Anna, Filomena Chierchia, Piotr Socha y Wojciech Szweda. "Shiga Toxin-Producing Escherichia coli in Faecal Samples from Wild Ruminants". Animals 13, n.º 5 (1 de marzo de 2023): 901. http://dx.doi.org/10.3390/ani13050901.
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Wildlife can harbour Shiga toxin-producing Escherichia coli (STEC). In the present study, STEC in faecal samples from red deer (n = 106) and roe deer (n = 95) were characterised. All isolates were non-O157 strains. In red deer, STEC were detected in 17.9% (n = 19) of the isolates, and the eae/stx2b virulence profile was detected in two isolates (10.5%). One STEC strain harboured stx1a (5.3%) and eighteen STEC strains harboured stx2 (94.7%). The most prevalent stx2 subtypes were stx2b (n = 12; 66.7%), stx2a (n = 3; 16.7%), and stx2g (n = 2; 11.1%). One isolate could not be subtyped (NS) with the applied primers (5.6%). The most widely identified serotypes were O146:H28 (n = 4; 21%), O146:HNM (n = 2; 10.5%), O103:H7 (n = 1; 5.3%), O103:H21 (n = 1; 5.3%), and O45:HNM (n = 1; 5.3%). In roe deer, STEC were detected in 16.8% (n = 16) of the isolates, and the eae/stx2b virulence profile was detected in one isolate (6.3%). Two STEC strains harboured stx1a (12.5%), one strain harboured stx1NS/stx2b (6.3%), and thirteen strains harboured stx2 (81.3%). The most common subtypes were stx2b (n = 8; 61.5%), stx2g (n = 2; 15.4%), non-typeable subtypes (NS) (n = 2; 15.4%), and stx2a (n = 1; 7.7%). Serotype O146:H28 (n = 5; 31.3%) was identified. The study demonstrated that the zoonotic potential of STEC strains isolated from wildlife faeces should be monitored in the context of the ‘One Health’ approach which links human health with animal and environmental health.
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Ferdous, Mithila, Kai Zhou, Alexander Mellmann, Stefano Morabito, Peter D. Croughs, Richard F. de Boer, Anna M. D. Kooistra-Smid, John W. A. Rossen y Alexander W. Friedrich. "Is Shiga Toxin-Negative Escherichia coli O157:H7 Enteropathogenic or Enterohemorrhagic Escherichia coli? Comprehensive Molecular Analysis Using Whole-Genome Sequencing". Journal of Clinical Microbiology 53, n.º 11 (26 de agosto de 2015): 3530–38. http://dx.doi.org/10.1128/jcm.01899-15.
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The ability ofEscherichia coliO157:H7 to induce cellular damage leading to disease in humans is related to numerous virulence factors, most notably thestxgene, encoding Shiga toxin (Stx) and carried by a bacteriophage. Loss of the Stx-encoding bacteriophage may occur during infection or culturing of the strain. Here, we collectedstx-positive andstx-negative variants ofE. coliO157:H7/NM (nonmotile) isolates from patients with gastrointestinal complaints. Isolates were characterized by whole-genome sequencing (WGS), and their virulence properties and phylogenetic relationship were determined. Because of the presence of theeaegene but lack of thebfpAgene, thestx-negative isolates were considered atypical enteropathogenicE. coli(aEPEC). However, they had phenotypic characteristics similar to those of the Shiga toxin-producingE. coli(STEC) isolates and belonged to the same sequence type, ST11. Furthermore, EPEC and STEC isolates shared similar virulence genes, the locus of enterocyte effacement region, and plasmids. Core genome phylogenetic analysis using a gene-by-gene typing approach showed that the sorbitol-fermenting (SF)stx-negative isolates clustered together with an SF STEC isolate and that one non-sorbitol-fermenting (NSF)stx-negative isolate clustered together with NSF STEC isolates. Therefore, thesestx-negative isolates were thought either to have lost the Stx phage or to be a progenitor of STEC O157:H7/NM. As detection of STEC infections is often based solely on the identification of the presence ofstxgenes, these may be misdiagnosed in routine laboratories. Therefore, an improved diagnostic approach is required to manage identification, strategies for treatment, and prevention of transmission of these potentially pathogenic strains.
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Cloke, Jonathan, Sharon Matheny, Michelle Swimley, Robert Tebbs, Angelia Burrell, Jonathan Flannery, Benjamin Bastin et al. "Validation of the Applied Biosystems RapidFinder Shiga Toxin–Producing E. coli (STEC) Detection Workflow". Journal of AOAC INTERNATIONAL 99, n.º 6 (1 de noviembre de 2016): 1537–54. http://dx.doi.org/10.5740/jaoacint.16-0235.
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Abstract The Applied Biosystems™ RapidFinder™ STEC Detection Workflow (Thermo Fisher Scientific) is a complete protocol for the rapid qualitative detection of Escherichia coli (E. coli) O157:H7 and the “Big 6” non-O157 Shiga-like toxin-producing E. coli (STEC) serotypes (defined as serogroups: O26, O45, O103, O111, O121, and O145). The RapidFinder STEC Detection Workflow makes use of either the automated preparation of PCR-ready DNA using the Applied Biosystems PrepSEQ™ Nucleic Acid Extraction Kit in conjunction with the Applied Biosystems MagMAX™ Express 96-well magnetic particle processor or the Applied Biosystems PrepSEQ Rapid Spin kit for manual preparation of PCR-ready DNA. Two separate assays comprise the RapidFinder STEC Detection Workflow, the Applied Biosystems RapidFinder STEC Screening Assay and the Applied Biosystems RapidFinder STEC Confirmation Assay. The RapidFinder STEC Screening Assay includes primers and probes to detect the presence of stx1 (Shiga toxin 1), stx2 (Shiga toxin 2), eae (intimin), and E. coli O157 gene targets. The RapidFinder STEC Confirmation Assay includes primers and probes for the “Big 6” non-O157 STEC and E. coli O157:H7. The use of these two assays in tandem allows a user to detect accurately the presence of the “Big 6” STECs and E. coli O157:H7. The performance of the RapidFinder STEC Detection Workflow was evaluated in a method comparison study, in inclusivity and exclusivity studies, and in a robustness evaluation. The assays were compared to the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS) Microbiology Laboratory Guidebook (MLG) 5.09: Detection, Isolation and Identification of Escherichia coli O157:H7 from Meat Products and Carcass and Environmental Sponges for raw ground beef (73% lean) and USDA/FSIS-MLG 5B.05: Detection, Isolation and Identification of Escherichia coli non-O157:H7 from Meat Products and Carcass and Environmental Sponges for raw beef trim. No statistically significant differences were observed between the reference method and the individual or combined kits forming the candidate assay using either of the DNA preparation kits (manual or automated extraction). For the inclusivity and exclusivity evaluation, the RapidFinder STEC Detection Workflow, comprising both RapidFinder STEC screening and confirmation kits, correctly identified all 50 target organism isolates and correctly excluded all 30 nontarget strains for both of the assays evaluated. The results of these studies demonstrate the sensitivity and selectivity of the RapidFinder STEC Detection Workflow for the detection of E. coli O157:H7 and the “Big 6” STEC serotypes in both raw ground beef and beef trim. The robustness testing demonstrated that minor variations in the method parameters did not impact the accuracy of the assay and highlighted the importance of following the correct incubation temperatures
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Novotna, R., P. Alexa, J. Hamrik, A. Madanat, J. Smola y A. Cizek. "Isolation and characterization Shiga toxin-producing Escherichia coli from sheep and goats inJordanwith evidence of multiresistant serotype O157:H7". Veterinární Medicína 50, No. 3 (28 de marzo de 2012): 111–18. http://dx.doi.org/10.17221/5603-vetmed.
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Ninety-three rectal swabs of lambs and young goats from two extensively and two intensively managed herds in Jordanwere taken and examined for Shiga toxin-producing Escherichia coli (STEC). The bacteriological examination included the preenrichment of rectal swabs in EC broth with novobiocin, and a subsequent parallel isolation on enterohemolysin agar and immunomagnetic separation with cultivation on CT-SMAC. The STEC O157:H7 strains were demonstrated in 8 of 32 diarrheic lambs 1- to 3-weeks old in one sheep herd with intensive milk production. In the remaining three herds, serogroups O128, O78, O15 and serotype O128:K85 of STEC strains were the most frequent findings. The presence of stx2, ehlyA and eaeA genes in all STEC O157:H7 isolates was confirmed by PCR. In two untypable STEC isolates, stx2 and ehlyA genes were detected. In other STEC non-O157 isolates, only stx1 a ehlyA genes were found. All STEC O157:H7 isolates were resistant against sulphonamides and chloramphenicol, five were also resistant against ampicillin and streptomycin, one against co-trimoxazole. One isolate was resistant against ampicillin, ampicillin-sulbactam, cephalosporins (cefazolin, cefuroxime), monobactams (aztreonam), sulphonamides, co-trimoxazole, aminoglycosides, tetracycline and chloramphenicol. Compared the resistant STEC O157:H7 isolates, the multiresistant isolate had a different RAPD pattern. Of 36 STEC non-O157 isolates, one isolate was resistant against sulphonamides and co-trimoxazole, and another one against ampicillin, streptomycin, sulphonamides and co-trimoxazole. STEC isolates resistant against antimicrobial agents were demonstrated only in herds with intensive management.
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Gonçalves, V. P. y J. M. Marin. "Fate of non O157 Shiga toxigenic Escherichia coli in composted cattle manure". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 59, n.º 4 (agosto de 2007): 825–31. http://dx.doi.org/10.1590/s0102-09352007000400001.
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To determine the fate of Shiga toxigenic Escherichia coli (STEC) non-O 157 in composted manure from naturally colonized cattle, fresh manure was obtained from three cows carrying non-O157 STEC strains possessing the stx2 gene. Two composting systems were used: a 0.6m deep cave opened in the soil and an one meter high solid manure heap in a pyramidal architecture. Every day, for the 10 first days, and every five days for a month, one manure sample from three different points in both systems was collected and cultured to determine the presence of E. coli and the presence of the stx 2 gene in the cells. The temperature was verified at each sampling. STEC non-O157 E. coli cells survived for 8, 25 and 30 days at 42, 40 and 38ºC, respectively, in the deep cave and 4, 4 and 7 days at 65, 58 and 52ºC, respectively, in the heap, during the composting manure. Temperature and indigenous microorganisms appear to contribute to pathogen disappearance in the composting system. It is concluded that both composting systems were efficient to eliminate STEC cells. Land application of composted manure should minimize environmental risk associated with the dissemination of the pathogen.
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Wang, Hongye, Muthu Dharmasena, Zhao Chen y Xiuping Jiang. "Persistence of Non-O157 Shiga Toxin–Producing Escherichia coli in Dairy Compost during Storage". Journal of Food Protection 80, n.º 12 (1 de noviembre de 2017): 1999–2005. http://dx.doi.org/10.4315/0362-028x.jfp-16-552.
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ABSTRACT Dairy compost with 20, 30, or 40% moisture content (MC) was inoculated with a mixture of six non-O157 Shiga toxin–producing Escherichia coli (STEC) serovars at a final concentration of 5.1 log CFU/g and then stored at 22 and 4°C for 125 days. Six storage conditions—4°C and 20% MC, 4°C and 30% MC, 4°C and 40% MC, 22°C and 20% MC, 22°C and 30% MC, and 22°C and 40% MC—were investigated for the persistence of non-O157 STEC in the dairy compost. During the entire storage, fluctuations in indigenous mesophilic bacterial levels were observed within the first 28 days of storage. After inoculation, the non-O157 STEC population increased 0.69 and 0.79 log CFU/g in the dairy compost with 30 and 40% MC at 22°C within the first day, respectively; for all other storage conditions, the pathogen population decreased rapidly. After the 125-day storage, the reductions of non-O157 STEC for 4°C and 20% MC, 4°C and 30% MC, 4°C and 40% MC, 22°C and 20% MC, 22°C and 30% MC, and 22°C and 40% MC storage conditions were >4.52, >4.55, 3.89, >4.61, 3.60, and 3.17 log CFU/g, respectively. All the survival curves showed an extensive tail, indicating non-O157 STEC can survive at least for 125 days in the dairy compost. The survival data were analyzed with log-linear with tailing and Weibull models. Compared with the log-linear with tailing model, the Weibull model was found to be a better choice for predicting the survival of non-O157 STEC in dairy compost owing to a high overall R2 value (0.8738 to 0.9909). The decay rate of non-O157 STEC was higher in dairy compost stored at 4°C compared with at 22°C, and the same trend was found for the compost with 40% MC versus 20% MC. In addition, two non-O157 STEC serotypes (STEC O145 and O45) were detected on the last day of the longitudinal study and may deserve special attention in the Big 6 STEC group. Our results have provided scientific data for risk assessment of the microbiological safety of dairy compost to control non-O157 STEC during subsequent storage of dairy compost.
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Zhang, Yujie, Yen-Te Liao, Xiaohong Sun y Vivian C. H. Wu. "Is Shiga Toxin-Producing Escherichia coli O45 No Longer a Food Safety Threat? The Danger is Still Out There". Microorganisms 8, n.º 5 (22 de mayo de 2020): 782. http://dx.doi.org/10.3390/microorganisms8050782.
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Many Shiga toxin-producing Escherichia coli (STEC) strains, including the serogroups of O157 and most of the top six non-O157 serotypes, are frequently associated with foodborne outbreaks. Therefore, they have been extensively studied using next-generation sequencing technology. However, related information regarding STEC O45 strains is scarce. In this study, three environmental E. coli O45:H16 strains (RM11911, RM13745, and RM13752) and one clinical E. coli O45:H2 strain (SJ7) were sequenced and used to characterize virulence factors using two reference E. coli O45:H2 strains of clinical origin. Subsequently, whole-genome-based phylogenetic analysis was conducted for the six STEC O45 strains and nine other reference STEC genomes, in order to evaluate their evolutionary relationship. The results show that one locus of enterocyte effacement pathogenicity island was found in all three STEC O45:H2 strains, but not in the STEC O45:H16 strains. Additionally, E. coli O45:H2 strains were evolutionarily close to E. coli O103:H2 strains, sharing high homology in terms of virulence factors, such as Stx prophages, but were distinct from E. coli O45:H16 strains. The findings show that E. coli O45:H2 may be as virulent as E. coli O103:H2, which is frequently associated with severe illness and can provide genomic evidence to facilitate STEC surveillance.
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CHATZIKYRIAKIDOU, K., R. R. GEIER, S. C. INGHAM y B. H. INGHAM. "Growth of Strains of the Major Non-O157 Shiga Toxin–Producing Escherichia coli Serogroups Is Not Different from Growth of Escherichia coli O157:H7 in Neutral Broth (pH 7.4) and Acidified Broth (pH 5.6) at 10°C". Journal of Food Protection 77, n.º 9 (1 de septiembre de 2014): 1617–23. http://dx.doi.org/10.4315/0362-028x.jfp-14-048.
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Understanding the survival and growth of non-O157 Shiga toxin–producing Escherichia coli (STEC) strains under cold temperatures may be important for protecting public health. The aim of this study was to compare the growth of three strains of each of the major non-O157 STEC serogroups (O26, O45, O103, O111, O121, and O145) with the growth of six O157:H7 STEC strains in broth at 10°C. Brain heart infusion broth (BHIB; pH 7.4) was inoculated with a single strain of stationary-phase STEC culture to produce a starting inoculum of ~106 CFU/ml and stored at 10°C for up to 96 h (three trials per strain). Populations over time were fitted to the Baranyi and Roberts model, and lag-phase duration (LPD) and growth rate were calculated for each strain per trial. Average LPD ranged from 9.2 to 32.8 h for non-O157 STEC and from 10.5 to 17.2 h for O157 STEC. One strain of O26 STEC had a significantly longer LPD (P < 0.05) than did the other strains (32.8 h); otherwise, no significant differences were noted (P > 0.05). Growth rate ranged from 0.031 to 0.060 log CFU/ml/h for non-O157 STEC strains and from 0.034 to 0.046 log CFU/ml/h for O157 STEC strains. No significant difference in growth rate was noted among strains in BHIB at pH 7.4 and 10°C. In subsequent trials, growth of a single strain of each of the non-O157 STEC serogroups was compared with growth of four acid-tolerant O157 STEC strains in BHIB acidified to pH 5.6 with lactic acid. Acidification generally increased LPD and decreased the growth rate for strains, although the effect was variable and not significant. These findings suggest that growth patterns for strains of non-O157 STEC are similar to those for strains of O157 STEC in neutral and pH 5.6 BHIB at 10°C. Further research is needed to determine whether strains behave similarly in meat systems.
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MAKINO, S., H. KOBORI, H. ASAKURA, M. WATARAI, T. SHIRAHATA, T. IKEDA, K. TAKESHI y T. TSUKAMOTO. "Detection and characterization of Shiga toxin-producing Escherichia coli from seagulls". Epidemiology and Infection 125, n.º 1 (agosto de 2000): 55–61. http://dx.doi.org/10.1017/s0950268899004100.
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Shiga toxin (Stx)-producing Escherichia coli (STEC) strains isolated from a seagull in Japan were examined. A total of 50 faecal samples was collected on a harbour bank in Hokkaido, Japan, in July 1998. Two different STEC strains, whose serotypes were O136[ratio ]H16 and O153[ratio ]H− , were isolated from the same individual by PCR screening; both of them were confirmed by ELISA and Vero cell cytotoxicity assay to be producing active Stx2 and Stx1, respectively. They harboured large plasmids, but did not carry the haemolysin or eaeA genes of STEC O157[ratio ]H7. Based on their plasmid profiles, antibiotic resistance patterns, pulsed-field gel electrophoresis analysis (PFGE), and the stx genes sequences, the isolates were different. Phylogenic analysis of the deduced Stx amino acid sequences demonstrated that the Stx toxins of seagull-origin STEC were closely associated with those of the human-origin, but not those of other animal-origin STEC. In addition, Stx2Φ-K7 phage purified from O136 STEC resembled Stx2Φ-II from human-origin O157[ratio ]H7, and was able to convert non-toxigenic E. coli to STEC. These results suggest that birds may be one of the important carriers in terms of the distribution of STEC.
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Rosser, Tracy, Tracy Dransfield, Lesley Allison, Mary Hanson, Nicola Holden, Judith Evans, Stuart Naylor, Roberto La Ragione, J. Christopher Low y David L. Gally. "Pathogenic Potential of Emergent Sorbitol-Fermenting Escherichia coli O157:NM". Infection and Immunity 76, n.º 12 (13 de octubre de 2008): 5598–607. http://dx.doi.org/10.1128/iai.01180-08.
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ABSTRACT Non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 is the primary Shiga toxin-producing E. coli (STEC) serotype associated with human infection. Since 1988, sorbitol-fermenting (SF) STEC O157:NM strains have emerged and have been associated with a higher incidence of progression to hemolytic-uremic syndrome (HUS) than NSF STEC O157:H7. This study investigated bacterial factors that may account for the increased pathogenic potential of SF STEC O157:NM. While no evidence of toxin or toxin expression differences between the two O157 groups was found, the SF STEC O157:NM strains adhered at significantly higher levels to a human colonic cell line. Under the conditions tested, curli were shown to be the main factor responsible for the increased adherence to Caco-2 cells. Notably, 52 of 66 (79%) European SF STEC O157:NM strains tested bound Congo red at 37οC and this correlated with curli expression. In a subset of strains, curli expression was due to increased expression from the csgBAC promoter that was not always a consequence of increased csgD expression. The capacity of SF STEC O157:NM strains to express curli at 37οC may have relevance to the epidemiology of human infections as curliated strains could promote higher levels of colonization and inflammation in the human intestine. In turn, this could lead to increased toxin exposure and an increased likelihood of progression to HUS.
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LIVEZEY, KRISTIN W., BETTINA GROSCHEL y MICHAEL M. BECKER. "Use of the ecf1 Gene To Detect Shiga Toxin–Producing Escherichia coli in Beef Samples". Journal of Food Protection 78, n.º 4 (1 de abril de 2015): 675–84. http://dx.doi.org/10.4315/0362-028x.jfp-14-417.
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Escherichia coli O157:H7 and six serovars (O26, O103, O121, O111, O145, and O45) are frequently implicated in severe clinical illness worldwide. Standard testing methods using stx, eae, and O serogroup–specific gene sequences for detecting the top six non-O157 STEC bear the disadvantage that these genes may reside, independently, in different nonpathogenic organisms, leading to false-positive results. The ecf operon has previously been identified in the large enterohemolysin-encoding plasmid of eae-positive Shiga toxin–producing E. coli (STEC). Here, we explored the utility of the ecf operon as a single marker to detect eae-positive STEC from pure broth and primary meat enrichments. Analysis of 501 E. coli isolates demonstrated a strong correlation (99.6%) between the presence of the ecf1 gene and the combined presence of stx, eae, and ehxA genes. Two large studies were carried out to determine the utility of an ecf1 detection assay to detect non-O157 STEC strains in enriched meat samples in comparison to the results using the U.S. Department of Agriculture Food Safety and Inspection Service (FSIS) method that detects stx and eae genes. In ground beef samples (n = 1,065), the top six non-O157 STEC were detected in 4.0% of samples by an ecf1 detection assay and in 5.0% of samples by the stx- and eae-based method. In contrast, in beef samples composed largely of trim (n = 1,097), the top six non-O157 STEC were detected at 1.1% by both methods. Estimation of false-positive rates among the top six non-O157 STEC revealed a lower rate using the ecf1 detection method (0.5%) than using the eae and stx screening method (1.1%). Additionally, the ecf1 detection assay detected STEC strains associated with severe illness that are not included in the FSIS regulatory definition of adulterant STEC.
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Dean-Nystrom, Evelyn A., Angela R. Melton-Celsa, Joachim F. L. Pohlenz, Harley W. Moon y Alison D. O'Brien. "Comparative Pathogenicity of Escherichia coli O157 and Intimin-Negative Non-O157 Shiga Toxin-Producing E. coli Strains in Neonatal Pigs". Infection and Immunity 71, n.º 11 (noviembre de 2003): 6526–33. http://dx.doi.org/10.1128/iai.71.11.6526-6533.2003.
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ABSTRACT We compared the pathogenicity of intimin-negative non-O157:H7 Shiga toxin (Stx)-producing Escherichia coli (STEC) O91:H21 and O104:H21 strains with the pathogenicity of intimin-positive O157:H7 and O157:H− strains in neonatal pigs. We also examined the role of Stx2d-activatable genes and the large hemolysin-encoding plasmid of O91:H21 strain B2F1 in the pathogenesis of STEC disease in pigs. We found that all E. coli strains that made wild-type levels of Stx caused systemic illness and histological lesions in the brain and intestinal crypts, whereas none of the control Stx-negative E. coli strains evoked comparable central nervous system signs or intestinal lesions. By contrast, the absence of intimin, hemolysin, or motility had little impact on the overall pathogenesis of systemic disease during STEC infection. The most striking differences between pigs inoculated with non-O157 STEC strains and pigs inoculated with O157 STEC strains were the absence of attaching and effacing intestinal lesions in pigs inoculated with non-O157:H7 strains and the apparent association between the level of Stx2d-activatable toxin produced by an STEC strain and the severity of lesions.
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Skinner, Craig, Guodong Zhang, Stephanie Patfield y Xiaohua He. "AnIn VitroCombined Antibiotic-Antibody Treatment Eliminates Toxicity from Shiga Toxin-Producing Escherichia coli". Antimicrobial Agents and Chemotherapy 59, n.º 9 (22 de junio de 2015): 5435–44. http://dx.doi.org/10.1128/aac.00763-15.
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ABSTRACTTreating Shiga toxin-producingEscherichia coli(STEC) gastrointestinal infections is difficult. The utility of antibiotics for STEC treatment is controversial, since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase the expression of Shiga toxins (Stxs), which are some of the most important virulence factors in STEC. Stxs contribute to life-threatening hemolytic uremic syndrome (HUS), which develops in considerable proportions of patients with STEC infections. Understanding the antibiotic resistance profiles of STEC isolates and the Stx induction potential of promising antibiotics is essential for evaluating any antibiotic treatment of STEC. In this study, 42 O157:H7 or non-O157 STEC isolates (including the “big six” serotypes) were evaluated for their resistance against 22 antibiotics by using an antibiotic array. Tigecycline inhibited the growth of all of the tested STEC isolates and also inhibited the production of Stxs (Stx2 in particular). In combination with neutralizing antibodies to Stx1 and Stx2, the tigecycline-antibody treatment fully protected Vero cells from Stx toxicity, even when the STEC bacteria and the Vero cells were cultured together. The combination of an antibiotic such as tigecycline with neutralizing antibodies presents a promising strategy for future STEC treatments.
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Hosking, Edan, Brooke Roman, Susan Alles, Mark Mozola, Susanne Hinkley, Karen Cooper, Danielle Keys et al. "NeoSeekTM STEC: A Multiplex Molecular Method for Detection and Identification of Select Shiga Toxin–Producing Escherichia coli in Beef". Journal of AOAC INTERNATIONAL 103, n.º 2 (marzo de 2020): 523–32. http://dx.doi.org/10.5740/jaoacint.19-0300.
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Abstract Background: NeoSeekTM STEC is a single-source, service-based method for detection and identification of select Shiga toxin–producing Escherichia coli (STEC), including E. coli O157:H7 and STEC of somatic groups O26, O45, O103, O111, O121, and O145. The method is a multiplex molecular method utilizing more than 80 genetic targets to identify STEC in complex matrices such as food enrichment cultures. Objective: A study was conducted to validate the NeoSeek method for detection of select STEC in raw beef trim. Methods: Performance of the NeoSeek STEC method was compared with that of the U.S. Department of Agriculture, Food Safety and Inspection Service reference methods for E. coli O157:H7 and non-O157 STEC for detection of E. coli O157:H7 and E. coli O26:H11 in raw beef trim. Additionally, inclusivity/exclusivity testing and method robustness testing were performed. Results: Results of raw beef trim testing showed no statistically significant differences in performance between the NeoSeek and reference methods in the ability to detect either E. coli O157:H7 or E.coli O26:H11, as determined by probability of detection analysis. Results of inclusivity and exclusivity testing showed 100% expected results with target and nontarget bacteria, with the exception of a single strain of E. coli O157:H7, which was subsequently verified to be stx-negative by PCR. Conclusions and Highlights: NeoSeek STEC is an accurate, reliable method for rapid detection and identification of select STEC in complex populations such as beef trim enrichment cultures.
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Marin, J. M., R. P. Maluta, C. A. Borges, L. G. Beraldo, S. A. Maesta, M. V. F. Lemos, U. S. Ruiz, F. A. Ávila y E. C. Rigobelo. "Fate of non O157 Shigatoxigenic Escherichia coli in ovine manure composting". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 66, n.º 6 (diciembre de 2014): 1771–78. http://dx.doi.org/10.1590/1678-6001.
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Livestock manure may contain pathogenic microorganisms which pose a risk to the health of animal or humans if the manure is not adequately treated or disposed of. To determine the fate of Shiga toxigenic Escherichia coli (STEC) non O157 in composted manure from naturally colonized sheep, fresh manure was obtained from animals carrying bacterial cells with stx1/ stx2 genes. Two composting systems were used, aerated and non-aerated, and the experiments were done in Dracena city, São Paulo State. Every week, for seven weeks, one manure sample from six different points in both systems was collected and cultured to determine the presence of E. coli, the presence of the virulence genes in the cells, and also the susceptibility to 10 antimicrobial drugs. The temperature was verified at each sampling. STEC non-O157 survived for 49 days in both composting systems. E. coli non-STEC showing a high degree of antibiotic resistance was recovered all long the composting period. No relationship was established between the presence of virulence genes and antibiotic resistance. The presence of virulence genes and multiple antibiotic resistances in E. coli implicates a potential risk for these genes spread in the human food chain, which is a reason for concern.
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Faulds, Nikki, Katharine Evans, Jessica Williams, Ana-Maria Leonte, David Crabtree, Katherine Church, Dean Leak et al. "Validation of the Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect™ Escherichia coli STEC Identification PCR Assay for the Detection of Escherichia coli O157:H7 and the Escherichia coli STEC Serotypes (O26, O45, O103, O111, O121, O145) from Fresh Raw Spinach, Fresh Baby Leaves, Fresh Cut Tomatoes, Frozen Raw Beef, Raw Beef Trim, and Beef Carcass Sponges: AOAC Performance Tested MethodSM 012102". Journal of AOAC INTERNATIONAL 105, n.º 2 (6 de octubre de 2021): 521–48. http://dx.doi.org/10.1093/jaoacint/qsab126.
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Abstract Background The Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect Escherichia coli STEC Identification PCR Assay are real-time PCR kits for the rapid detection of E. coli O157:H7 and non-E. coli O157 Shiga toxin-producing E. coli (STEC) serotypes (O26, O45, O103, O111, O121, O145) from fresh raw spinach, fresh baby leaves, fresh cut tomatoes, frozen raw beef, raw beef trim, and beef carcass sponges. Objective Both assays were evaluated for AOAC®Performance Tested MethodsSM certification. Methods Detection and confirmation inclusivity/exclusivity, matrix, product consistency and stability, and robustness studies were conducted. In the matrix studies, the candidate method was validated against United States and international reference methods for STEC serotypes. Results Matrix studies showed no statistically significant differences between the candidate and reference method results when analyzed by probability of detection. For each inclusivity/exclusivity study, all inclusivity strains and no exclusivity strains were detected by either kit. Robustness testing demonstrated that the identification assay performed reliably despite method deviations; however, although not statistically significant, the screening assay performance was impacted. Product consistency and stability testing demonstrated no statistically significant differences between kit lots and storage time points. Conclusion The data presented show that both assays constitute a rapid and reliable workflow for the detection and confirmation of E. coli O157:H7 and stipulated non-E. coli O157:H7 STEC serotypes from the tested matrixes. Highlights Results are obtained in 80 min post-enrichment with both assays run simultaneously, allowing for the detection and confirmation of STEC within a single workflow.
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Faulds, Nikki, Katharine Evans, Jessica Williams, Ana-Maria Leonte, David Crabtree, Katherine Church, Dean Leak et al. "Validation of the Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect™ Escherichia coli STEC Identification PCR Assay for the Detection of Escherichia coli O157:H7 and the Escherichia coli STEC Serotypes (O26, O45, O103, O111, O121, O145) from Fresh Raw Spinach, Fresh Baby Leaves, Fresh Cut Tomatoes, Frozen Raw Beef, Raw Beef Trim, and Beef Carcass Sponges: AOAC Performance Tested MethodSM 012102". Journal of AOAC INTERNATIONAL 105, n.º 2 (6 de octubre de 2021): 521–48. http://dx.doi.org/10.1093/jaoacint/qsab126.
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Abstract Background The Thermo Scientific SureTect™ Escherichia coli O157:H7 and STEC Screening PCR Assay and SureTect Escherichia coli STEC Identification PCR Assay are real-time PCR kits for the rapid detection of E. coli O157:H7 and non-E. coli O157 Shiga toxin-producing E. coli (STEC) serotypes (O26, O45, O103, O111, O121, O145) from fresh raw spinach, fresh baby leaves, fresh cut tomatoes, frozen raw beef, raw beef trim, and beef carcass sponges. Objective Both assays were evaluated for AOAC®Performance Tested MethodsSM certification. Methods Detection and confirmation inclusivity/exclusivity, matrix, product consistency and stability, and robustness studies were conducted. In the matrix studies, the candidate method was validated against United States and international reference methods for STEC serotypes. Results Matrix studies showed no statistically significant differences between the candidate and reference method results when analyzed by probability of detection. For each inclusivity/exclusivity study, all inclusivity strains and no exclusivity strains were detected by either kit. Robustness testing demonstrated that the identification assay performed reliably despite method deviations; however, although not statistically significant, the screening assay performance was impacted. Product consistency and stability testing demonstrated no statistically significant differences between kit lots and storage time points. Conclusion The data presented show that both assays constitute a rapid and reliable workflow for the detection and confirmation of E. coli O157:H7 and stipulated non-E. coli O157:H7 STEC serotypes from the tested matrixes. Highlights Results are obtained in 80 min post-enrichment with both assays run simultaneously, allowing for the detection and confirmation of STEC within a single workflow.
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Qin, Xuan, Eileen J. Klein, Emmanouil Galanakis, Anita A. Thomas, Jennifer R. Stapp, Shannon Rich, Anne Marie Buccat y Phillip I. Tarr. "Real-Time PCR Assay for Detection and Differentiation of Shiga Toxin-Producing Escherichia coli from Clinical Samples". Journal of Clinical Microbiology 53, n.º 7 (29 de abril de 2015): 2148–53. http://dx.doi.org/10.1128/jcm.00115-15.
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Timely accurate diagnosis of Shiga toxin-producingEscherichia coli(STEC) infections is important. We evaluated a laboratory-developed real-time PCR (LD-PCR) assay targetingstx1,stx2, andrfbEO157with 2,386 qualifying stool samples submitted to the microbiology laboratory of a tertiary care pediatric center between July 2011 and December 2013. Broth cultures of PCR-positive samples were tested for Shiga toxins by enzyme immunoassay (EIA) (ImmunoCard STAT! enterohemorrhagicE. coli[EHEC]; Meridian Bioscience) and cultured in attempts to recover both O157 and non-O157 STEC.E. coliO157 and non-O157 STEC were detected in 35 and 18 cases, respectively. Hemolytic uremic syndrome (HUS) occurred in 12 patients (10 infected with STEC O157, one infected with STEC O125ac, and one with PCR evidence of STEC but no resulting isolate). Among the 59 PCR-positive STEC specimens from 53 patients, only 29 (54.7%) of the associated specimens were toxin positive by EIA. LD-PCR differentiated STEC O157 from non-O157 usingrfbEO157, and LD-PCR results prompted successful recovery ofE. coliO157 (n= 25) and non-O157 STEC (n= 8) isolates, although the primary cultures and toxin assays were frequently negative. A rapid “mega”-multiplex PCR (FilmArray gastrointestinal panel; BioFire Diagnostics) was used retrospectively, and results correlated with LD-PCR findings in 25 (89%) of the 28 sorbitol-MacConkey agar culture-negative STEC cases. These findings demonstrate that PCR is more sensitive than EIA and/or culture and distinguishes between O157 and non-O157 STEC in clinical samples and thatE. coliO157:H7 remains the predominant cause of HUS in our institution. PCR is highly recommended for rapid diagnosis of pediatric STEC infections.
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Babolhavaeji, Kiandokht, Leili Shokoohizadeh, Morteza Yavari, Abbas Moradi y Mohammad Yousef Alikhani. "Prevalence of Shiga Toxin-Producing Escherichia coli O157 and Non-O157 Serogroups Isolated from Fresh Raw Beef Meat Samples in an Industrial Slaughterhouse". International Journal of Microbiology 2021 (15 de diciembre de 2021): 1–6. http://dx.doi.org/10.1155/2021/1978952.
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Background. The aims of the current study are the identification of O157 and non-O157 Shiga Toxin-Producing Escherichia coli (STEC) serogroups isolated from fresh raw beef meat samples in an industrial slaughterhouse, determination of antimicrobial resistance patterns, and genetic linkage of STEC isolates. Materials and Methods. A total of 110 beef samples were collected from the depth of the rump of cattle slaughtered at Hamadan industrial slaughterhouse. After detection of E. coli isolates, STEC strains were identified according to PCR for stx1, stx2, eaeA, and hlyA virulence genes, and STEC serogroups (O157 and non-O157) were identified by PCR. The genetic linkage of STEC isolates was analyzed by the ERIC- (Enterobacterial Repetitive Intergenic Consensus-) PCR method. The antimicrobial susceptibility of STEC isolates was detected by the disk diffusion method according to CLSI guidelines. Results. Among 110 collected beef samples, 77 (70%) were positive for E. coli. The prevalence of STEC in E. coli isolates was 8 (10.4%). The overall prevalence of O157 and non-O157 STEC isolates was 12.5% (one isolate) and 87.5% (7 isolates), respectively. The hemolysin gene was detected in 25% (2 isolates) of STEC strains. Evaluation of antibiotic resistance indicated that 100% of STEC isolates were resistant to ampicillin, ampicillin-sulbactam, amoxicillin-clavulanic acid, and cefazolin. Resistance to tetracycline and ciprofloxacin was detected in 62.5% and 12.5% of isolates, respectively. The analysis of the ERIC-PCR results showed five different ERIC types among the STEC isolates. Conclusion. The isolation of different clones STECs from beef and the presence of antibiotic-resistant isolates indicate that more attention should be paid to the hygiene of slaughterhouses.
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PAOLI, GEORGE C., CHANDI WIJEY y GAYLEN A. UHLICH. "Genetically Marked Strains of Shiga Toxin–Producing O157:H7 and Non-O157 Escherichia coli: Tools for Detection and Modeling†". Journal of Food Protection 78, n.º 5 (1 de mayo de 2015): 888–901. http://dx.doi.org/10.4315/0362-028x.jfp-14-472.
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Shiga toxin–producing E. coli (STEC) is an important group of foodborne pathogens in the United States and worldwide. Nearly half of STEC-induced diarrheal disease in the United States is caused by serotype O157:H7, while non-O157 STEC account for the remaining illnesses. Thus, the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service has instituted regulatory testing of beef products and has a zero-tolerance policy for regulatory samples that test positive for STEC O157:H7 and six other non-O157 STEC (serogroups O26, O45, O103, O111, O121, and O145). In this study, positive control (PC) strains for the detection of STEC O157:H7 and the six USDA-regulated non-O157 STEC were constructed. To ensure that the food testing samples are not cross-contaminated by the PC sample, it is important that the STEC-PC strains are distinguishable from STEC isolated from test samples. The PC strains were constructed by integrating a unique DNA target sequence and a gene for spectinomycin (Sp) resistance into the chromosomes of the seven STEC strains. End-point and real-time PCR assays were developed for the specific detection of the PC strains and were tested using 93 strains of E. coli (38 STEC O157:H7, at least 6 strains of each of the USDA-regulated non-O157 STEC, and 2 commensal E. coli) and 51 strains of other bacteria (30 species from 20 genera). The PCR assays demonstrated high specificity for the unique target sequence. The target sequence was detectable by PCR after 10 culture passages (~100 generations), demonstrating the stability of the integrated target sequence. In addition, the strains were tested for their potential use in modeling the growth of STEC. Plating the PC strains mixed with ground beef flora on modified rainbow agar containing Sp eliminated the growth of the background flora that grew on modified rainbow agar without Sp. Thus, these strains could be used to enumerate and model the growth of STEC in the presence of foodborne background flora.
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Byrne, Lisa, Gemma L. Vanstone, Neil T. Perry, Naomi Launders, Goutam K. Adak, Gauri Godbole, Kathie A. Grant, Robin Smith y Claire Jenkins. "Epidemiology and microbiology of Shiga toxin-producing Escherichia coli other than serogroup O157 in England, 2009–2013". Journal of Medical Microbiology 63, n.º 9 (1 de septiembre de 2014): 1181–88. http://dx.doi.org/10.1099/jmm.0.075895-0.
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The implementation of direct testing of clinical faecal specimens for gastrointestinal (GI) pathogens by PCR offers a sensitive and comprehensive approach for the detection of Shiga toxin-producing Escherichia coli (STEC). The introduction of a commercial PCR assay, known as GI PCR, for the detection of GI pathogens at three frontline hospital laboratories in England between December 2012 and December 2013 led to a significant increase in detection of STEC other than serogroup O157 (non-O157 STEC). In 2013, 47 isolates were detected in England, compared with 57 in the preceding 4 years (2009–2012). The most common non-O157 STEC serogroup detected was O26 (23.2 %). A total of 47 (47.5 %) STEC isolates had stx2 only, 28 (28.3 %) carried stx1 and stx2, and the remaining 24 (24.2 %) had stx1 only. Stx2a (64.0 %) was the most frequently detected Stx2 subtype. The eae (intimin) gene was detected in 52 (52.5 %) non-O157 STEC isolates. Six strains of STEC O104 had aggR, but this gene was not detected in any other STEC serogroups in this study. Haemolytic ureamic syndrome was significantly associated with STEC strains possessing eae [odds ratio (OR) 5.845, P = 0.0235] and/or stx2a (OR 9.56, P = 0.0034) subtypes. A matched case–control analysis indicated an association between non-O157 STEC cases and contact with farm animals. Widespread implementation of the PCR approach in England will determine the true incidence of non-O157 STEC infection, highlight the burden in terms of morbidity and mortality, and facilitate the examination of risk factors to indicate whether there are niche risk exposures for particular strains.
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TSENG, M., Q. SHA, J. T. RUDRIK, J. COLLINS, T. HENDERSON, J. A. FUNK y S. D. MANNING. "Increasing incidence of non-O157 Shiga toxin-producing Escherichia coli (STEC) in Michigan and association with clinical illness". Epidemiology and Infection 144, n.º 7 (20 de noviembre de 2015): 1394–405. http://dx.doi.org/10.1017/s0950268815002836.
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SUMMARYInfection with Shiga toxin-producing Escherichia coli (STEC) by serotypes other than O157 (non-O157) have been increasingly reported in the United States. This increase in reporting is primarily due to the improvements in diagnostic tests. We analysed 1497 STEC cases reported in Michigan from 2001 to 2012. A significant increase in the number of non-O157 STEC cases was observed over time, and similar incidence rates were observed for O157 and non-O157 STEC cases in certain time periods. The odds of hospitalization was two times higher in O157 STEC cases relative to non-O157 STEC cases when adjusted for age and gender, suggesting that O157 STEC causes more severe clinical outcomes in all age groups. The use of population-based surveillance to better define trends and associations with disease severity are critical to enhance our understanding of STEC infections and improve upon current prevention and control efforts.
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Lonczynski, Thomas y Laura Cowin. "The Validation of the SIMUL-qPCR Top 7 STEC Assay Collection: AOAC Performance Tested MethodSM 022001". Journal of AOAC INTERNATIONAL 104, n.º 4 (23 de enero de 2021): 1098–108. http://dx.doi.org/10.1093/jaoacint/qsab006.
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Abstract Background The Simultaneous Multiplex Real Time PCR (SIMUL-qPCR) Top 7 STEC Assay Collection is a quick, reliable method for detecting top seven Shiga toxin-producing Escherichia coli (STEC) in raw beef trim, raw ground beef, and beef carcass sampling sheets. Each assay multiplexes several targets in one run to identify E. coli O157: H7, O26, O45, O103, O111, O121, O145, Shiga toxin, and intimin genes. This collection uses specifically optimized proprietary media for single-step recovery and enrichment of enterohemorrhagic E. coli. Objective This report details the method validation study to validate raw beef trim, raw ground beef, and beef carcass sampling sheets. Method Matrix studies for raw beef trim, raw ground beef, and beef carcass sampling sheets, inclusivity/exclusivity, product consistency/stability, and robustness testing were conducted to assess the method’s performance. Results Fifty top seven STEC isolates were analyzed with the SIMUL-qPCR assay. Thirty-two isolates, including closely related non-E. coli species and E. coli non-STEC strains, were also tested. Inclusivity showed the collection detected the Shiga toxin (stx) gene, intimin (eae) gene, and top seven serogroups. None of the 32 exclusivity strains were detected. The candidate and reference methods’ results had no statistically significant differences during matrix studies. Small variations in critical test parameters (enrichment time, extraction reagent volume, and extracted sample volume) did not adversely affect the assay’s performance, and stability testing indicated consistent results for at least one year. Conclusions The data presented demonstrate that the SIMUL-qPCR Top 7 STEC Assay is a reliable method for detecting the top seven STEC. Highlights The Applied Food Diagnostics, Inc. Simultaneous Multiplex Real Time PCR (SIMUL-qPCR) Top 7 STEC Assay is capable of detecting the top seven Shiga toxin-producing Escherichia coli in beef trim, ground beef, and beef carcass sampling sheets in as little as 10 hours of enrichment.
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Tolen, Tamra, Yicheng Xie, Thomas Hairgrove, Jason Gill y T. Taylor. "Evaluation of Commercial Prototype Bacteriophage Intervention Designed for Reducing O157 and Non-O157 Shiga-Toxigenic Escherichia coli (STEC) on Beef Cattle Hide". Foods 7, n.º 7 (16 de julio de 2018): 114. http://dx.doi.org/10.3390/foods7070114.
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Microbiological safety of beef products can be protected by application of antimicrobial interventions throughout the beef chain. This study evaluated a commercial prototype antimicrobial intervention comprised of lytic bacteriophages formulated to reduce O157 and non-O157 Shiga-toxigenic Escherichia coli (STEC) on beef cattle hide pieces, simulating commercial pre-harvest hide decontamination. STEC reduction in vitro by individual and cocktailed phages was determined by efficiency of plating (EOP). Following STEC inoculation onto hide pieces, the phage intervention was applied and hide pieces were analyzed to quantify reductions in STEC counts. Phage intervention treatment resulted in 0.4 to 0.7 log10 CFU/cm2 (p < 0.01) E. coli O157, O121, and O103 reduction. Conversely, E. coli O111 and O45 did not show any significant reduction after application of bacteriophage intervention (p > 0.05). Multiplicity of infection (MOI) evaluation indicated E. coli O157 and O121 isolates required the fewest numbers of phages per host cell to produce host lysis. STEC-attacking phages may be applied to assist in preventing STEC transmission to beef products.
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Tanyitiku, Mary Nkongho, Graeme Nicholas, Jon J. Sullivan, Igor C. Njombissie Petcheu y Stephen L. W. On. "Survival of Escherichia coli in Edible Land Snails: Implications for Heliciculture and Public Health". Pathogens 13, n.º 3 (26 de febrero de 2024): 204. http://dx.doi.org/10.3390/pathogens13030204.
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Background: Land snails are considered a delicacy in many countries in Europe and sub-Saharan Africa. However, the interaction of microbial pathogens with land snails may present a public health threat when handling and/or consuming snails. This study examines the survival of Escherichia coli in edible land snails in a model system. Methods: Well-studied Shigatoxigenic (STEC) and non-STEC strains were compared. Mature Helix spp. were experimentally fed with E. coli-inoculated oats for 48 h. The snail feces after inoculation were periodically sampled and cultured for a 30-day period and subjected to microbiological analyses. Results: The average rate of decline of the non-STEC strain CSH-62 in the feces of live snails was significantly (p < 0.05) faster than that of STEC ERL 06-2503. In addition, the viable population of E. coli ERL 06-2503 significantly (p < 0.05) persisted for a longer time in the intestine of land snails than E. coli CSH-62. Conclusion: The results showed that the viable population of the E. coli strains examined demonstrated first-order kinetics, and their survival (CFU/mL) appeared significantly (p < 0.05) dependent on the E. coli pathotype. In addition, the continuous enumeration of E. coli in snail faeces indicated that land snails could serve as a mode of transmission of microbial pathogens to susceptible hosts, including humans. Further research is recommended to better quantify the direct and indirect health risks of pathogen transmission by edible snails to humans.
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CELIK, G., A. DIKICI y A. KOLUMAN. "Survival of Shiga Toxin-Producing Escherichia coli (STEC) Serogroups During Production and Storage of Yogurt". Journal of the Hellenic Veterinary Medical Society 72, n.º 1 (9 de abril de 2021): 2689. http://dx.doi.org/10.12681/jhvms.26753.
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In this study, the survival of Escherichia coli O157:H7 and non-O157 STEC serogroups of O26, O111, O103, and O145 were investigated during production and storage of yogurt. For this purpose, pathogens were individually inoculated into milk after pasteurization along with the starter culture (approximately 7.00±1.00 log10 cfu/g). After incubation at 44oC (about 180 min), yogurt samples were capped and stored at 4oC for 20 days. Pathogens were enumerated at 0, 5, 10, 15, and 20th days of storage. Lactic acid content (%) and pH of the samples were also screened. Moreover, mesophilic Lactococcus spp. and mesophilic Lactobacillus spp. were enumerated during production of yogurt.After incubation, the number of E. coli O157, O26, O103, O145, O111were 6.76±0.45, 6.64±0.53, 7.12±0.43, 6.00±1.39, 5.89±1.37 log10 cfu/g, respectively. A significant decrease was determined in all groups during the storage of yogurt samples at 4oC (p<0.05). It was detected on the 20th day of storage that the number of E. coli O157:H7 and non-O157 STEC serogroups of O103 and O145 were under the detection limit. However, STEC O26 and O111 were viable around 1.51±0.98 and 1.18±0.62 log10 cfu/g respectively. Results of the study showed that Escherichia coli O157:H7 and non-O157 STEC serogroups might pose a potential health risk during production and storage of yogurt.
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Islam, Mohammad A., Abdus S. Mondol, Enne de Boer, Rijkelt R. Beumer, Marcel H. Zwietering, Kaisar A. Talukder y Annet E. Heuvelink. "Prevalence and Genetic Characterization of Shiga Toxin-Producing Escherichia coli Isolates from Slaughtered Animals in Bangladesh". Applied and Environmental Microbiology 74, n.º 17 (18 de julio de 2008): 5414–21. http://dx.doi.org/10.1128/aem.00854-08.
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ABSTRACT To determine the prevalence of Shiga toxin (Stx)-producing Escherichia coli (STEC) in slaughter animals in Dhaka, Bangladesh, we collected rectal contents immediately after animals were slaughtered. Of the samples collected from buffalo (n = 174), cows (n = 139), and goats (n = 110), 82.2%, 72.7%, and 11.8% tested positive for stx 1 and/or stx 2, respectively. STEC could be isolated from 37.9%, 20.1%, and 10.0% of the buffalo, cows, and goats, respectively. STEC O157 samples were isolated from 14.4% of the buffalo, 7.2% of the cows, and 9.1% of the goats. More than 93% (n = 42) of the STEC O157 isolates were positive for the stx 2, eae, katP, etpD, and enterohemorrhagic E. coli hly (hly EHEC) virulence genes. STEC O157 isolates were characterized by seven recognized phage types, of which types 14 (24.4%) and 31 (24.4%) were predominant. Subtyping of the 45 STEC O157 isolates by pulsed-field gel electrophoresis showed 37 distinct restriction patterns, suggesting a heterogeneous clonal diversity. In addition to STEC O157, 71 STEC non-O157 strains were isolated from 60 stx-positive samples from 23.6% of the buffalo, 12.9% of the cows, and 0.9% of the goats. The STEC non-O157 isolates belonged to 36 different O groups and 52 O:H serotypes. Unlike STEC O157, most of the STEC non-O157 isolates (78.9%) were positive for stx 1. Only 7.0% (n = 5) of the isolates were positive for hly EHEC, and none was positive for eae, katP, and etpD. None of the isolates was positive for the iha, toxB, and efa1 putative adhesion genes. However, 35.2% (n = 25), 11.3% (n = 8), 12.7% (n = 9), and 12.7% (n = 9) of the isolates were positive for the lpf O113, saa, lpfA O157/01-141, and lpfA O157/OI-154 genes, respectively. The results of this study provide the first evidence that slaughtered animals like buffalo, cows, and goats in Bangladesh are reservoirs for STEC, including the potentially virulent STEC strain O157.
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Arthur, Terrance M., Genevieve A. Barkocy-Gallagher, Mildred Rivera-Betancourt y Mohammad Koohmaraie. "Prevalence and Characterization of Non-O157 Shiga Toxin-Producing Escherichia coli on Carcasses in Commercial Beef Cattle Processing Plants". Applied and Environmental Microbiology 68, n.º 10 (octubre de 2002): 4847–52. http://dx.doi.org/10.1128/aem.68.10.4847-4852.2002.
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ABSTRACT Beef carcass sponge samples collected from July to August 1999 at four large processing plants in the United States were surveyed for the presence of non-O157 Shiga toxin-producing Escherichia coli (STEC). Twenty-eight (93%) of 30 single-source lots surveyed included at least one sample containing non-O157 STEC. Of 334 carcasses sampled prior to evisceration, 180 (54%) were found to harbor non-O157 STEC. Non-O157 STEC isolates were also recovered from 27 (8%) of 326 carcasses sampled after the application of antimicrobial interventions. Altogether, 361 non-O157 STEC isolates, comprising 41 different O serogroups, were recovered. O serogroups that previously have been associated with human disease accounted for 178 (49%) of 361 isolates. Although 40 isolates (11%) carried a combination of virulence factor genes (enterohemorrhagic E. coli hlyA, eae, and at least one stx gene) frequently associated with STEC strains causing severe human disease, only 12 of these isolates also belonged to an O serogroup previously associated with human disease. Combining previously reported data on O157-positive samples (R. O. Elder, J. E. Keen, G. R. Siragusa, G. A. Barkocy-Gallagher, M. Koohmaraie, and W. W. Laegreid, Proc. Natl. Acad. Sci. USA 97:2999-3003, 2000) with these data regarding non-O157-positive samples indicated total STEC prevalences of 72 and 10% in preevisceration and postprocessing beef carcass samples, respectively, showing that the interventions used by the beef-processing industry effected a sevenfold reduction in carcass contamination by STEC.
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LIAO, YEN-TE, MARKUS F. MILLER, GUY H. LONERAGAN, J. CHANCE BROOKS, ALEJANDRO ECHEVERRY y MINDY M. BRASHEARS. "Non-O157 Shiga Toxin–Producing Escherichia coli in U.S. Retail Ground Beef". Journal of Food Protection 77, n.º 7 (1 de julio de 2014): 1188–92. http://dx.doi.org/10.4315/0362-028x.jfp-13-518.
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Shiga toxin–producing Escherichia coli (STEC) serotype O157:H7 and serogroups O26, O45, O103, O111, O121, and O145 are the leading cause of STEC-associated infections in humans in the United States. In the United States, these organisms are considered adulterants in raw nonintact beef products and in intact beef destined to be made into or used in nonintact raw beef products. The objective of this study was to provide an estimate of the burden of the six serogroups of non-O157 STEC in ground beef obtained from retail stores across the United States. A convenience sample of commercial ground beef products (n = 1,129) were purchased from retail stores in 24 states from October 2011 to May 2012. The samples had various lean/fat proportions, muscle group of origin (chuck, round, sirloin, or not specified), and packaging types. For each ground beef sample, 25 g was inoculated in 225 ml of modified tryptic soy broth, stomached for 1 min, and then incubated at 41°C for 18 ± 2 h. These enrichment cultures were then screened for stx, eae, and O group genes using a commercially available, closed-platform PCR-based method. The potential positive samples were subjected to immunomagnetic separation and plated on modified Rainbow agar. Morphologically typical colonies were subjected to latex agglutination and PCR determination of stx and eae genes. Nine (0.8%) of the ground beef samples were potentially positive for at least one STEC serogroup after PCR screening. The serogroups detected by PCR assay were O26 (four samples), O103 (four samples), O145 (three samples), O45 (two samples), and O121 (one sample). No STEC isolates belonging to these serogroups were recovered from the sample cultures. The current research provides updated surveillance data for non-O157 STEC isolates among commercial ground beef products and information regarding the potential sources of contamination from different parts of beef trims destined for ground beef production.
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GÓMEZ-ALDAPA, CARLOS A., ESMERALDA RANGEL-VARGAS, M. del REFUGIO TORRES-VITELA, ANGÉLICA VILLARRUEL-LÓPEZ y JAVIER CASTRO-ROSAS. "Behavior of Non-O157 Shiga Toxin–Producing Escherichia coli, Enteroinvasive E. coli, Enteropathogenic E. coli, and Enterotoxigenic E. coli Strains on Alfalfa Sprouts". Journal of Food Protection 76, n.º 8 (1 de agosto de 2013): 1429–33. http://dx.doi.org/10.4315/0362-028x.jfp-13-060.
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Data about the behavior of non-O157 Shiga toxin–producing Escherichia coli (non-O157 STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), and enteropathogenic E. coli (EPEC) on seeds and alfalfa sprouts are not available. The behavior of STEC, EIEC, ETEC, and EPEC was determined during germination and sprouting of alfalfa seeds at 20 ± 2°C and 30 ± 2°C and on alfalfa sprouts at 3 ± 2°C. When alfalfa seeds were inoculated with STEC, EIEC, ETEC, or EPEC strains, all these diarrheagenic E. coli pathotypes (DEPs) grew during germination and sprouting of seeds, reaching counts of approximately 5 and 6 log CFU/g after 1 day at 20 ± 2°C and 30 ± 2°C, respectively. However, when the sprouts were inoculated after 1 day of seed germination and stored at 20 ± 2°Cor30 ± 2°C, no growth was observed for any DEP during sprouting at 20 ± 2°Cor 30 ± 2°C for 9 days. Refrigeration reduced significantly (P < 0.0.5) the number of viable DEPs on sprouts after 20 days in storage; nevertheless, these decreases have no practical significance for the safety of the sprouts.
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Ismaili, Arif, Elaine McWhirter, Michelle Y. C. Handelsman, James L. Brunton y Philip M. Sherman. "Divergent Signal Transduction Responses to Infection with Attaching and Effacing Escherichia coli". Infection and Immunity 66, n.º 4 (1 de abril de 1998): 1688–96. http://dx.doi.org/10.1128/iai.66.4.1688-1696.1998.
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ABSTRACT Shiga toxin-producing Escherichia coli (STEC) O157:H7 is an attaching and effacing pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome. Although this organism causes adhesion pedestals, the cellular signals responsible for the formation of these lesions have not been clearly defined. We have shown previously that STEC O157:H7 does not induce detectable tyrosine phosphorylation of host cell proteins upon binding to eukaryotic cells and is not internalized into nonphagocytic epithelial cells. In the present study, tyrosine-phosphorylated proteins were detected under adherent STEC O157:H7 when coincubated with the non-intimately adhering, intimin-deficient, enteropathogenic E. coli(EPEC) strain CVD206. The ability to be internalized into epithelial cells was also conferred on STEC O157:H7 when coincubated with CVD206 ([158 ± 21] % of control). Neither the ability to rearrange phosphotyrosine proteins nor that to be internalized into epithelial cells was evident following coincubation with another STEC O157:H7 strain or with the nonsignaling espB mutant of EPEC.E. coli JM101(pMH34/pSSS1C), which overproduces surface-localized O157 intimin, also rearranged tyrosine-phosphorylated and cytoskeletal proteins when coincubated with CVD206. In contrast, JM101(pMH34/pSSS1C) demonstrated rearrangement of cytoskeletal proteins, but not tyrosine-phosphorylated proteins, when coincubated with intimin-deficient STEC (strains CL8KO1 and CL15). These findings indicate that STEC O157:H7 forms adhesion pedestals by mechanisms that are distinct from those in attaching and effacing EPEC. Taken together, these findings point to diverging signal transduction responses to infection with attaching and effacing bacterial enteropathogens.
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GLASS, KATHLEEN A., CHARLES W. KASPAR, JEFFREY J. SINDELAR, ANDREW L. MILKOWSKI, BRIAN M. LOTZ, JIHUN KANG, NANCY G. FAITH, ELENA ENACHE, AI KATAOKA y CRAIG HENRY. "Validation of Pepperoni Process for Control of Shiga Toxin–Producing Escherichia coli". Journal of Food Protection 75, n.º 5 (1 de mayo de 2012): 838–46. http://dx.doi.org/10.4315/0362-028x.jfp-11-486.
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The objective of this study was to compare the survival of non-O157 Shiga toxin–producing Escherichia coli (STEC) with E. coli O157:H7 during pepperoni production. Pepperoni batter was inoculated with 7 log CFU/g of a seven-strain STEC mixture, including strains of serotypes O26, O45, O103, O111, O121, O145, and O157. Sausages were fermented to pH ≤4.8, heated at 53.3°C for 1 h, and dried for up to 20 days. STEC strains were enumerated at designated intervals on sorbitol MacConkey (SMAC) and Rainbow (RA) agars; enrichments were completed in modified EC (mEC) broth and nonselective tryptic soy broth (TSB). When plated on SMAC, total E. coli populations decreased 2.6 to 3.5 log after the 1-h heating step at 53.3°C, and a 4.9- to 5-log reduction was observed after 7 days of drying. RA was more sensitive in recovering survivors; log reductions on it were 1.9 to 2.6, 3.8 to 4.2, and 4.6 to 5.3 at the end of cook, and at day 7 and day 14 of drying, respectively. When numbers were less than the limit of detection by direct plating on days 14 and 20 of drying (representing a 5-log kill), no more than one of three samples in each experiment was positive by enrichment with mEC broth; however, STEC strains were recovered in TSB enrichment. Freezing the 7-day dried sausage for 2 to 3 weeks generated an additional 1- to 1.5-log kill. Confirmation by PCR revealed that O103 and O157 had the greatest survival during pepperoni productions, but all serotypes except O111 and O121 were occasionally recovered during drying. This study suggests that non-O157 STEC strains have comparable or less ability than E. coli O157 to survive the processing steps involved in the manufacture of pepperoni. Processes suitable for control of E. coli O157 will similarly inactivate the other STEC strains tested in this study.
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Hajra, Tapas K., Prasanta K. Bag, Suresh C. Das, Souryadeep Mukherjee, Asis Khan y T. Ramamurthy. "Development of a Simple Latex Agglutination Assay for Detection of Shiga Toxin-Producing Escherichia coli (STEC) by Using Polyclonal Antibody against STEC". Clinical and Vaccine Immunology 14, n.º 5 (7 de marzo de 2007): 600–604. http://dx.doi.org/10.1128/cvi.00342-06.
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ABSTRACT Rabbit antiserum raised against the whole-cell antigen of Shiga toxin-producing Escherichia coli (STEC) strain VT3 (stx 1 + stx 2 + eae +) was repeatedly adsorbed with heat-killed cells of different non-STEC strains and other enteric bacteria. Thus, the antiserum obtained was designated VT3 antiserum. VT3 antiserum reacted with intimin type γ. We assessed the reactivity of VT3 antiserum to whole-cell lysates of 87 strains of E. coli and other enteric bacteria by immunoblotting. The antiserum recognized the 97-kDa protein in whole-cell lysate from strain VT3, and 36 (83.7%) of the 43 STEC strains were positive for the STEC antigen. None of the non-STEC strains or strains of other species examined tested positive by immunoblotting. Based on this result, we developed a latex agglutination assay for the detection of STEC strains. Thirty-five (81.4%) of the 43 STEC strains tested positive for the STEC antigen by the latex agglutination assay. One (3.3%) of the 30 non-STEC strains and none of the strains of the other enteric bacteria included in this study tested positive by the latex agglutination assay. The corresponding specificity of the latex agglutination assay was approximately 98%. Results of this study showed the production of STEC antiserum and the generation of a simple, cost-effective, sensitive, and specific latex agglutination assay for establishing an etiological diagnosis of STEC.
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EKIRI, ABEL B., DOUGLAS LANDBLOM, DAWN DOETKOTT, SUSAN OLET, WEILIN L. SHELVER y MARGARET L. KHAITSA. "Isolation and Characterization of Shiga Toxin–Producing Escherichia coli Serogroups O26, O45, O103, O111, O113, O121, O145, and O157 Shed from Range and Feedlot Cattle from Postweaning to Slaughter". Journal of Food Protection 77, n.º 7 (1 de julio de 2014): 1052–61. http://dx.doi.org/10.4315/0362-028x.jfp-13-373.
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Cattle are the main reservoirs for Shiga toxin–producing Escherichia coli (STEC) strains. E. coli O26, O45, O103, O111, O121, O145, and O157 are among the STEC serogroups that cause severe foodborne illness and have been declared as adulterants by the U.S. Department of Agriculture, Food Safety and Inspection Service. The objectives of this study were (i) to estimate the prevalence of non-O157 STEC and E. coli O157 in naturally infected beef cows and in steer calves at postweaning, during finishing, and at slaughter and (ii) to test non-O157 STEC isolates for the presence of virulence genes stx1, stx2, eaeA, and ehlyA. Samples were collected from study animals during multiple sampling periods and included fecal grabs, rectal swabs, and midline sponge samples. Laboratory culture, PCR, and multiplex PCR were performed to recover and identify E. coli and the virulence genes. The prevalence of non-O157 STEC (serogroups O26, O45, O103, O111, O121, O113, and O145) fecal shedding ranged from 8% (4 of 48 samples) to 39% (15 of 38 samples) in cows and 2% (1 of 47 samples) to 38% (9 of 24 samples) in steer calves. The prevalence of E. coli O157 fecal shedding ranged from 0% (0 of 38 samples) to 52% (25 of 48 samples) in cows and 2% (1 of 47 samples) to 31% (15 of 48 samples) in steer calves. In steer calves, the prevalence of non-O157 STEC and E. coli O157 was highest at postweaning, at 16% (15 of 96 samples) and 23% (22 of 96 samples), respectively. Among the 208 non-O157 STEC isolates, 79% (164 isolates) had stx1, 79% (165 isolates) had stx2, and 58% (121 isolates) had both stx1 and stx2 genes. The percentage of non-O157 STEC isolates encoding the eaeA gene was low; of the 165 isolates tested, 8 (5%) were positive for eaeA and 135 (82%) were positive for ehlyA. Findings from this study provide further evidence of non-O157 STEC shedding in beef cows and steer calves particularly at the stage of postweaning and before entry into the feedlot.
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Ghaderi, P., E. Ahmadi, A. M. Farrokhi, F. Moshrefi, A. Rezaei, K. Siavashi, Q. Ghavami, K. Rahmani y A. Sharifi. "Prevalence and molecular characterisation of Shiga toxin-producing Escherichia coli in sheep farms of Sanandaj, Iran". BULGARIAN JOURNAL OF VETERINARY MEDICINE 27, n.º 2 (2024): 206–14. http://dx.doi.org/10.15547/bjvm.2022-0056.
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Shiga toxin-producing Escherichia coli (STEC) strains have emerged as important foodborne pathogens of global public health concern, causing life-threatening diseases. Animals and their products have been documented as important reservoirs for STECs, especially E. coli O157. The aim of this study was to investigate STECs from healthy and diarrhoeic sheep in Sanandaj, Iran. In the current study, a total of 81 sheep faecal samples were taken (22 from diarrhoeic sheep and 59 from healthy sheep). E. coli and subsequently STEC strains was detected according to standard protocol (cultural characterisation and PCR assays). Finally, the frequency of Shiga-toxin producing gene(s) (stx1, stx2), intimin (eaeA) and enterohaemolysin (hlyA) was detected among STEC isolates using duplex PCR. Totally, 42 E. coli were isolated from 81 faecal samples (51.85% contamination). Of these, 34 isolates (80.9%) were identified as STEC patotypes based on Sorbitol-MacConkey (SMAC) medium culturing and also the presence of stx1 and/or stx2. Of these, only 3 isolates (7.1%) were identified as serotype O157:H7 based on PCR assay. In addition, the results showed that STEC bacteria were significantly more prevalent in diarrhoeic samples than in healthy samples (50% vs. 22.1%). Overall, the PCR results showed that 33 (97%), 12 (35.3%) and 8 (23.5%) isolates carried stx1, stx2 and hlyA, respectively. The eaeA gene was not found in any isolate. The number of isolated STEC bacteria in spring (10 isolates) and winter (14 isolates) were significantly higher than those in summer (4 isolates) and autumn (6 isolates) (P=0.039). Also, the number of STEC in diarrhoea samples was significantly higher compared to non-diarrhoea samples (P=0.032). In conclusion, the present study revealed high prevalence rate of STEC including serotype O157:H7 and non-O157:H7 in sheep faeces which highlights the importance of sheep as a reservoir of STEC pathogen in Sanandaj region. Therefore, additional control and preventive measures must be undertaken to control the contamination by this pathogen.
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Elmonir, Walid, Etab Mohamed Abo Remela y Yasmine Alwakil. "Diversity, virulence and antibiogram traits of Escherichia coli recovered from potable water sources in Gharbia, Egypt". Journal of Water and Health 18, n.º 3 (13 de marzo de 2020): 430–38. http://dx.doi.org/10.2166/wh.2020.239.
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Abstract This study aimed to assess the public health risk of coliforms and Escherichia coli contamination of potable water sources in Egypt. A total of 150 water samples (100 tap and 50 well) were collected from five districts in Gharbia governorate, Egypt. High rates of coliforms contamination were recorded in 52 and 76% of examined tap and well water samples, respectively. E. coli strains were detected in 16% of the water samples (15% tap water and 18% well water; 23.7% rural and 8.1% urban). Rural water sources were 3.5 times more likely to be contaminated than urban sources (P = 0.01). Eight (33.3%) E. coli isolates were Shiga toxin-producing E. coli (STEC). Multiple drug resistance (MDR) was observed for 62.5% of the isolates. Seven (29.2%) E. coli isolates harboured at least one of the extended-spectrum beta-lactamase (ESBL) genes. The majority (87.5%) of the STEC isolates were MDRs and harboured ESBL genes. STEC isolates were significantly more likely to resist six classes of antibiotics than non-STEC isolates. This is the first report of potable water contamination with MDR-STEC in Egypt. This study highlights an alarming public health threat that necessitates preventive interventions for public and environmental safety.