Letteratura scientifica selezionata sul tema "Escherichia coli O1113"

RESUMO Este trabalho teve como objetivo determinar a prevalência de Escherichia coli produtoras de Shigatoxinas (STEC) e E. coli dos sorogrupos O157, O111 e O113 em rebanhos leiteiros do Município de Jaboticabal, SP, Brasil. A presença de sequências gênicas stx1, stx2e eae foi detectada pela reação em cadeia da polimerase (PCR) em amostras de fezes. Todas as amostras stx e eae positivas foram submetidas a uma nova reação de PCR para detecção das sequências rfb O157, O111 e O113. Observou-se uma alta prevalência (72,16%) de sequências stx nas fezes dos bovinos, sendo que o perfil genotípico encontrado com maior frequência foi o stx1 associado à stx2. Os coeficientes de prevalência das sequências rfb O157, O111 e O113 foram, respectivamente, 14,77%, 0,2% e 30,83%. Animais de todos os rebanhos (100%) apresentaram em suas fezes STEC e E. coli O113 e os sorogrupos O157 e O111 foram observados em 60,0% e 10,0% dos rebanhos, respectivamente. Concluiu-se que a alta prevalência de STEC detectada em rebanho leiteiro evidenciada nas fezes de bovinos desempenham um papel importante na contaminação ambiental e podem oferecerrisco de agravo à saúde pública.

The problems associated with identification and characterization of non-O157 verotoxin-producing Escherichia coli (VTEC) are discussed. The paradox of VTEC is that most reports of human illnesses are associated with serotypes such as O157:H7, O111:H– (nonmotile), O26:H11, and O113:H21, which are rarely found in domestic animals. However, those VTEC serotypes commonly found in domestic animals, especially ruminants, rarely cause human illnesses. When they cause human illnesses, the symptoms are similar to those caused by the serotypes E. coli O157:H7, O111:H–, O26:H11, and O113:H21. The impact of VTEC on human and animal health is also addressed. The VTEC and their toxicity are considered as a paradigm for emerging pathogens. The question on how such pathogens could arise from a basic commensal population is also addressed.

ABSTRACT Shiga toxigenic Escherichia coli (STEC) strains are a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, eae-positive STEC strains, particularly those belonging to serogroups O157 and O111, appear to have greater virulence for humans. However, in spite of beingeae negative, STEC strains belonging to serogroup O113 have frequently been associated with cases of severe STEC disease, including hemolytic-uremic syndrome (HUS). Western blot analysis with convalescent-phase serum from a patient with HUS caused by an O113:H21 STEC strain indicated that human immune responses were directed principally against lipopolysaccharide O antigen. Accordingly, the serum was used to isolate a clone expressing O113 O antigen from a cosmid library of O113:H21 DNA constructed in E. coli K-12. Sequence analysis indicated that the O113 O-antigen biosynthesis (rfb) locus contains a cluster of nine genes which may be cotranscribed. Comparison with sequence databases identified candidate genes for four glycosyl transferases, an O-acetyl transferase, an O-unit flippase, and an O-antigen polymerase, as well as copies of galE and gnd. Two additional, separately transcribed genes downstream of the O113 rfbregion were predicted to encode enzymes involved in synthesis of activated sugar precursors, one of which (designated wbnF) was essential for O113 O-antigen synthesis, and so is clearly a part of the O113 rfb locus. Interestingly, expression of O113 O antigen by E. coli K-12 significantly increased in vitro adherence to both HEp-2 and Henle 407 cells.

Shiga toxigenic Escherichia coli (STEC) strains are a diverse group of organisms associated with severe gastrointestinal and systemic diseases in humans. Within the STEC family,eae-positive STEC strains, particularly those belonging to serogroups O157 and O111, appear to have greater virulence for humans. However, in spite of being eae negative, STEC strains belonging to serogroup O113 have frequently been associated with cases of severe STEC disease, including hemolytic-uremic syndrome (HUS). We have developed a modified multiplex PCR assay for detection of STEC strains belonging to these three serogroups in cultures of feces by using primers specific for portions of the genetic loci (rfb) encoding biosynthesis of the respective O antigen. These primers direct amplification of PCR products of 259, 406, and 593 bp for serogroups O157, O111, and O113, respectively. The assay was validated by testing 40 previously characterized STEC strains, with 100% agreement. It also detected STEC strains of the appropriate genotype in primary fecal cultures from 13 patients with HUS or bloody diarrhea. Thirty other primary fecal cultures from patients without evidence of STEC infection were negative.

Shiga toxigenic Escherichia coli (STEC) strains are a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, certain strains appear to have greater virulence for humans. STEC strains carryingeae and belonging to serogroup O157 or O111 have been responsible for the vast majority of outbreaks of STEC disease reported to date. Here we describe a STEC O113:H21 strain lackingeae that was responsible for a cluster of three cases of hemolytic-uremic syndrome. This strain produces a single Stx2-related toxin and adheres efficiently to Henle 407 cells.

The pathogenicity and fecal shedding of enterohemorrhagic Escherichia coli (EHEC) O26:H11, O111:NM, and O157:H7 were compared in calves (<1 week of age) with or without prior treatment with probiotic bacteria (competitive exclusion E. coli). Three groups of 12 to 14 calves were used for these treatments. Half of the calves in each group were perorally administered 1010 CFU of probiotic bacteria per calf, and, 2 days thereafter, 108 CFU of a five-strain mixture with one of the three EHEC serotypes per calf were administered to each calf. None of the EHEC serotypes caused clinical disease, and neither gross nor microscopic lesions attributable to EHEC were detected in control or probiotic-treated calves at necropsy. In calves administered E. coli O157:H7, fecal shedding was greatly reduced (>6 log10 CFU/g) by 8 days after administration, and there was no significant difference (P > 0.05) in fecal shedding of E. coli O157:H7 between probiotic-treated and untreated control groups at that time. In contrast, control calves perorally administered E. coli of serotypes O111:NM or O26:H11 continued to shed substantial populations (102.1 to 106 CFU/g of feces and 102.5 to 104.9 CFU/g of feces, respectively) throughout 7 days postadministrationof EHEC. In both groups administered either E. coli O111:NM or O26:H11, significantly less (P < 0.05) EHEC was isolated from feces at 7 days postadministration of EHEC and at necropsy from the probiotic-treated group than from the untreated control group. Overall, neonatal calves shed in the feces from 1 to 7 days following peroral administration of EHEC greater populations of E. coli O111:NM and O26:H11 than E. coli O157:H7. In addition, treatment of calves with probiotic E. coli reduced fecal shedding of E. coli O111:NM and O26:H11 in most calves.

The fecal shedding and pathogenicity of enterohemorrhagic E. coli (EHEC) O26:H11, EHEC O111:NM, and EHEC O157:H7 in weaned calves (8 to 10 weeks of age) were compared with and without treatment with a three-strain mixture of probiotic bacteria (competitive-exclusion E. coli). Three groups of 12 calves were each perorally given a five-strain mixture of one of the EHEC serotypes (1010 CFU of total bacteria per calf). Seventy-two hours later, six calves from each group were each administered 1010 CFU of probiotic bacteria. None of the EHEC serotypes caused significant clinical disease, although a few calves developed mild transient diarrhea or pyrexia. Gross or microscopic lesions attributable to EHEC were not detected in control or probiotic-treated calves at necropsy. For probiotic-treated calves given E. coli O157:H7 and for probiotic-treated calves given E. coli O111:NM, fecal shedding was reduced compared with that for untreated calves. For the probiotic-treated calves given E. coli O157:H7, the reductions in fecal shedding on days 8, 12, 14, 16, 20, 22, 28, and 30 after peroral administration were statistically significant (P < 0.05). For probiotic-treated calves given E. coli O111:NM, there were statistically significant reductions (P < 0.05) in fecal shedding on days 6, 8, 10, and 12. In contrast, there was no reduction in fecal shedding for calves administered E. coli O26:H11 and treated with the probiotic bacteria. In fact, calves in both the treated and the nontreated groups continued to shed large populations of E. coli O26:H11 throughout the 32-day trial. At necropsy, E. coli O157:H7 was isolated from five of six untreated calves and from only two of six probiotic-treated calves. E. coli O111:NM was isolated from four of six untreated calves at necropsy and from two of six probiotic-treated calves. However, E. coli O26:H11 was isolated from five of six untreated calves and from all six probiotic-treated calves. The results obtained in this study indicate that probiotic E. coli substantially reduced or eliminated fecal shedding of E. coli O157:H7 and E. coli O111:NM 8 to 30 days and 6 to 12 days after the administration of the probiotic culture, respectively, and reduced the persistence of E. coli O157:H7 in the gastrointestinal tract at necropsy (31 to 33 days after the administration of the probiotic culture). The probiotic E. coli did not reduce fecal shedding or gastrointestinal persistence of E. coli O26:H11.

Rapid and high-throughput identification and serotyping of Shiga toxin–producing Escherichia coli (STEC) O serogroups is important for detecting, investigating, and controlling STEC infection outbreaks and removing hazardous products from commerce. A Luminex microbead-based suspension array has been developed to identify the 11 most clinically relevant STEC serogroups: O26, O45, O91, O103, O104, O111, O113, O121, O128, O145, and O157. Here we present results of a blinded multilaboratory collaborative study involving 10 participants from nine laboratories using 55 unknown strains. From the total 495 analyses, two false-positive and three false-negative results were obtained, indicating the assay to be a rapid, high-throughput, and robust method for identifying clinically relevant STEC serogroups.

ABSTRACT A promising approach to developing a vaccine against O111 strains of diarrheagenic Escherichia coli that exhibit different mechanisms of virulence is to target either the core or the polysaccharide chain (O antigen) of their lipopolysaccharide (LPS). However, due to structural variations found in both these LPS components, to use them as antigen targets for vaccination, it is necessary to formulate a vaccine able to induce a humoral immune response that can recognize all different variants found in E. coli O111 strains. In this study, it was demonstrated that, despite differences in composition of oligosaccharide repeat units between O111ab and O111ac LPS subtypes, antibodies against one O111 subtype can recognize and inhibit the adhesion to human epithelial cells of all categories of O111 E. coli (enteropathogenic E. coli [EPEC], enterohemorrhagic E. coli [EHEC], and enteroaggregative E. coli [EAEC]) strains regardless of the nature of their flagellar antigens, mechanisms of virulence, or O111 polysaccharide subtypes. These antibodies were also able to increase the clearance of different strains of O111 E. coli by macrophages. PCR analyses of the pathways involved in O111 LPS core biosynthesis showed that all EAEC strains have core type R2, whereas typical EPEC and EHEC have core type R3. In contrast, atypical EPEC strains have core types R2 and R3. In summary, the results presented herein indicate that the O111 polysaccharide and LPS core types R2 and R3 are antigen targets for panspecific immunotherapy against all categories of O111 E. coli.

"February 2003." Addendum and corrigenda inserted at back Includes bibliographical references (leaves 249-272) Aims to identify and characterise potential virulence-associated factors from the locus of enterocyte effacement-negative shiga-toxigenic Escherichia coli O113:H21 strain 98NK2 which was responsible for an outbreak of haemolytic uremic syndrome. Particular attention was focused on putative virulence genes encoded on the megaplasmid of this strain.

E. coli pertencentes ao sorogrupo O111 são incluem amostras com diferentes fatores de virulência que são responsáveis por gastroenterites por todo o mundo e surtos de diarreia com sangue e síndrome hemolítico-urêmica em países desenvolvidos. Resultados obtidos anteriormente mostraram que o LPS O111 é um bom candidato a antígeno para a formulação de uma vacina contra E. coli O111. Desta forma, o polissacarídeo O111 foi conjugado com proteínas arreadoras. Coelhos foram imunizados pela via subcutânea com o conjugado O111-citocromo c incorporado em sílica SBA-15 como adjuvante, os resultados mostraram que os anticorpos obtidos foram capazes de reconhecer e inibir a adesão de todas as categorias de E. coli pertencentes ao sorogrupo O111. O veículo carreador de antígeno, VaxcineTM , foi incorporado no conjugado O111-EtxB e camundongos foram imunizados pela via oral, o que resultou em resposta imune sistêmica e de mucosa contra o LPS O111. Os anticorpos obtidos foram capazes de reconhecer amostras de todas as categorias de E. coli O111. Os dados obtidos neste trabalho sugerem que a utilização do polissacarídeo O111 em uma formulação conjugada é capaz de prevenir surtos de diarreia causada por E. coli O111 independente do seu mecanismo de virulência.
The E. coli serogroup O111 include samples with different virulence factors that are responsible for enteritis throughout the world and for outbreaks of bloody diarrhea and hemolytic uremic syndrome in developed countries. Previous results obtained have shown that O111 LPS is a good candidate antigen for the development of a vaccine against E. coli O111. Therefore, the polysaccharide was conjugated with carrier proteins. Rabbits were immunized subcutaneously with the O111-cytochrome c conjugate incorporated in silica SBA-15 as an adjuvant, the results obtained show that the antibodies were able to recognize and inhibit the adhesion of all types of E. coli belonging to serogroup O111. The antigen delivery vehicle, VaxcineTM was incorporated into the O111-EtxB conjugate, and mice were immunized by gavage, resulting in systemic and mucosal immune response against O111 LPS. These antibodies were able to recognize all categories of E. coli O111. The results presented in this work indicate that an oral conjugated vaccine that targets the O111 antigen has the potencial to prevent diarrhea by O111 E. coli strains, regardless their mechanism of virulence.

This study presents a duplex real-time PCR assay for the detection of vtl and vt2 genes in ovine carcass swabs, ovine fleece, bovine hide swabs and bovine faecal samples, using TaqMan probes. Sample matrices were spiked with a cocktail of VTEC (E. coli 0157, 026, 0111,0103 and 0145) and enriched for 6 h in mTSB. The resultant DNA was extracted and real-time PCR performed using specific primer/TaqMan probe sets for vti and vt2 genes. Detection was achieved for both low level (approximately 10 cfu/sample) and high level (approximately 10,000 cfu/sample) in all four matrices tested. This study also presents data on the carriage and transfer of verocytotoxigenic Escherichia coli (VTEC) 0157, 026, 0111, 0103 and 0145 from faeces and hide/fleece to dressed carcasses of Irish cattle and sheep as well as establishing the virulence potential of VTEC carried by these animals. Individual animals were tracked and faecal samples, hidelfleece and carcass swabs were analysed for verocytotoxin (vtl and vt2) genes using a duplex real-time PCR assay. Positive samples were screened for the five serogroups of interest by real-time PCR. Isolates were recovered from PCR positive samples using immunomagnetic separation and confirmed by latex agglutination and PCR. Isolates were subject to a virulence screen (vti, vt2, eaeA and hlyA) by PCR. VTEC isolates were examined by Pulsed-Field Gel Electrophoresis (PFGE). This study shows that while VTEC 0157 are being carried by cattle and sheep presented for slaughter in Ireland, a number of other verocytotoxin producing strains (particularly E. coli 026) are beginning to emerge and confirms that that emerging VTEC serogroups should be monitored throughout the food chain.

Enterohämorrhagische E. coli (EHEC) gehören zu den wichtigen, lebensmittelassoziierten Erregern von Gastroenteritiden. Schwere Erkrankungsverläufe, wie die postinfektiöse Komplikation HUS sind bekannt und betreffen meist Kinder unter 5 Lebensjahren. Als Primärquelle gelten Wiederkäuer, in deren Gastrointestinaltrakt das natürliche Habitat von Shigatoxin-bildenden E. coli liegt. Über fäkale Kontamination von Lebensmitteln, Wasser oder auch direkten Kontakt können STEC oral vom Menschen aufgenommen werden, wobei nicht alle STEC gleich virulent sind. Manche, wie z. B. die der Serogruppen O26, O103, O111, O145 und O157 werden wesentlich häufiger bei erkrankten Menschen nachgewiesen als andere. Ziel dieser Studie war es zum einen fünf Singleplex Real-Time PCR-Systeme und ein Pentaplex Real-Time PCR-System zum Nachweis der oben genannten fünf E. coli-Serogruppen am LGL, Oberschleißheim, zu etablieren. Die in der Norm ISO/TS 13136:2012 als „hochpathogen“ eingestuften STEC-Stämme können somit anhand der dort beschriebenen Primer- und Sondensequenzen aus Probenisolaten detektiert werden. Für die Validierung wurden die Selektivität, Sensitivität, Präzision und Richtigkeit der PCR-Systeme bestimmt. Zum anderen wurden die Daten von 8272 humanen Proben (einschließlich der des EHEC O104:H4-Ausbruchs von 2011), 1521 Lebensmittelproben, 240 Tierkotproben, 69 Schlachtkörperproben und 29 Wasserproben aus den Jahren 2009 bis 2011 aus Bayern sowie die STEC-Serotypisierungsergebnisse von 09/2004 bis 12/2011 ausgewertet und beschrieben. Im Vergleich mit der gängigen Serotypisierung mittels Agglutination bietet das Real-Time PCR-Verfahren insbesondere bei großem Probenumfang einen enormen Zeitvorteil. Das Pentaplex PCR-System ermöglicht zudem eine zeitgleiche Analyse von Probenisolaten auf alle fünf Serogruppen. Alle E. coli-Stämme der Serogruppen O26, O103, O111, O145 und O157 wurden durch die PCR-Systeme korrekt nachgewiesen. Die O103-Sondensequenz wurde hierfür zuvor modifiziert. Die Spezifität der Nachweissysteme für O26, O103 und O145 lag in Bezug auf E. coli bei 100 %. Bei den Nachweissystemen für O111 und O157 zeigten auch Bakterienstämme anderer Gattungen ein positives Ergebnis in der PCR (Serratia entomophila / rfbEO157-positiv und Shigella sp. LGL 2869 / wbd1O111-positiv). Die Datenauswertung ergab unter anderem einen hohen Anteil stx-positiver Tierkot- und Schlachtkörperproben von Rindern. Die meisten stx-positiven Lebensmittel stammten von Wiederkäuern. Vereinzelt waren auch potenziell humanvirulente STEC nachzuweisen. Der Großteil der nicht-humanen Proben war weder eae- noch EhlyA-positiv, während nur ein Viertel der humanen Proben keines der beiden Gene aufwies. Bei humanen Proben dominiert die Gruppe der unter 1 bis 5-jährigen Erkrankten und Frauen sind häufiger betroffen als Männer. Die E. coli-Serogruppen O26, O103, O111, O145 und O157 gehören zu den häufigsten in Bayern und 2011 infizierten sich 47 Menschen in Bayern mit EHEC O104:H4.
Enterohemorrhagic E. coli belong to the important, food-associated pathogens that cause gastrointestinal infections. Serious courses of disease such as the postinfectious complication HUS are well known and majorly affect children below the age of five. Ruminants are considered as primary source and their gastrointestinal tract is the natural habitat of Shigatoxin-producing E. coli. STEC can be ingested by humans through faecal contamination of food and water but also through direct contact, even though not all STEC show the same degree of virulence. Some of them, for instance those belonging to the serogroups O26, O103, O111, O145 and O157, are considerably more frequently detected in sick humans than others. On the one hand, the aim of this study at the LGL, Oberschleißheim, was to establish both, five Singleplex real-time PCR-systems and one Pentaplex real-time PCR-system in order to detect the five E. coli serogroups mentioned above. This enables to detect the strains of E. coli, which according to ISO/TS 13136:2012 are rated “highly pathogenic” to humans by means of primer and probe sequences described in this ISO technical specification. Selectivity, sensitivity, precision, and trueness of the real-time PCR-systems were determined for validation. On the other hand, data of 8.272 human samples (including those belonging to the outbreak of EHEC O104:H4 in 2011), 1.521 food samples, 240 samples of animal faeces, 69 samples of carcasses, and 29 samples of water (from 2009 until 2011) as well as the results of STEC-serotyping, conducted between 09/2004 and 12/2011, were evaluated and described. In comparison with common serotyping through agglutination, real-time PCR offers a decisive time advantage, especially in terms of handling larger amounts of samples. In addition, the Pentaplex PCR-system enables a simultaneous analysis of sample isolates on all five serogroups. All E. coli strains that belong to the serogroups O26, O103, O111, O145 and O157 were detected correctly through the PCR-systems. The probe sequence of O103 was previously modified for this purpose. The specificity of the O26, O103 and O145 detection systems was referring to E. coli equivalent to 100 percent. But the detection systems for O111 and O157 showed positive results in bacterial strains of different genera (Serratia entomophila / rfbEO157-positive and Shigella sp. LGL 2869 / wbd1O111-positive). Data evaluation showed a high share of stx-positive bovine faeces and carcasses samples. Most of stx-positive food is originated in ruminants. Occasionally STEC that are potentially human pathogenic were detected. The bulk of non-human samples were neither eae- nor EhlyA-positive, whereas only a quarter of the human samples showed none of these two genes. Among the human samples those patients less than one to five years of age prevailed, and women were more often affected than men. The E. coli serogroups O26, O103, O111, O145 and O157 belong to the most common in Bavaria and in 2011 47 people were infected with EHEC O104:H4.