Articles de revues : « Environmental bacterial isolates »

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Pattani, Vivek B. « Characterization of Plant Growth-Promoting Activity of Bacteria Isolated from Forest and Coastal Regions of Saurashtra, Gujarat, India ». Bioscience Biotechnology Research Communications 15, n^o 1 (25 mars 2022) : 144–51. http://dx.doi.org/10.21786/bbrc//15.1.22.

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The haphazard application of chemical fertilizers and pesticides causes tremendous damage to ecosystems and all biota. One of the most effective ways to tackle the threat is to use biofertilizer. Plant growth promoting bacteria (PGPB) are an important bacterial source for microbial fertilizers that can boost agricultural yields by encouraging plant growth. Bacterial isolates isolated from Saurashtra region, Gujarat, India were analysed for their capability to solubilize inorganic 'P' from tri calcium phosphate and production of indole acetic acid (IAA) quantitatively by bacterial. Production of ammonia, siderophore and hydrogen cyanide (HCN) by selected bacteria isolates was analysed. Biochemical characterization of selected bacterial isolates was done using Vitek 2 Compact system. Isolate GFS15C2 showed highest amount of phosphate solubilization, followed by isolate GFS07C1 and GFS01C1. Bacterial isolate GFS15C2 produced highest amount of IAA. All bacterial isolates were able produce ammonia. Eight bacteria isolates were be to produce HCN. Siderophore was produced by 14 bacterial isolates. In biochemical characterization all the bacterial isolates were able to use D-glucose. Based on biochemical characters clustering of bacteria isolates was done using Paleontological statistics software package for education and data analysis(PAST). Using cluster analysis by euclidean distance method based on biochemical characterization isolates GFS16C2 & SCS12C3 was found to have distinct characters than other isolates. The present study attempts to characterize PGPB which could be harnessed to improve plant growth. Several phosphate solubilizers and IAA producers also showed production of siderophores and HCN which suggests that these organisms do possess biocontrol ability. These PGPB microbial inoculants can be utilized to improve agricultural systems or as an alternate means of environmentally friendly plant disease biocontrol.

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Kurniawan, Ardiansyah, Suci Puspita Sari, Euis Asriani, Andi Kurniawan, Abu Bakar Sambah et Asep Awaludin Prihanto. « Molecular Identification of Cellulolytic Bacteria From Mangrove Sediment at Tin Minning Region In West Bangka ». International Journal of Applied Biology 3, n^o 1 (29 juin 2019) : 7. http://dx.doi.org/10.20956/ijab.v3i1.5848.

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Cellulose as an abundant source of glucose in Indonesia requires acceleration of decomposition utilizing cellulolytic bacteria. Cellulolytic bacteria can be obtained from the isolation of mangrove organic matter, such as sediments. Muntok Sub-district is one of the regions with the most tin mining in West Bangka Regency also has mangroves in the coastal area. Exploration of cellulolytic bacteria in mangroves with different environmental characteristics encourages researchers to find new bacterial strains that produce cellulase enzymes with new properties. Thirteen isolates were successfully isolated from three locations. Tembelok mangrove sediments produced Seven bacterial isolates, Peltim Mangrove samples produced three isolates and from Sukal Mangrove three isolates were obtained. Seven isolates showed clear zones in the Lugol test and three isolates including were gram-positive bacteria. Molecular test with 16S rRNA analysis showed TBL1 isolate has 85% similar identity of Vibrio parahaemolyticus strain HY3 and TBL2 isolate has 98% similar identity of Bacillus amyloliquefaciens strain HS8. Bacillus amyloliquefaciens potential to further study as cellulose degrading bacteria for feed ingredients.

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Abid, Suhad A., Sarah Naji Aziz, Noor Al-Huda Ali A. H. Saeed, Shaimaa N. Mizil, Israa M. S. Al-Kadmy, Nadheema H. Hussein, Nadal Al-Saryi, Susan A. Ibrahim et Jumaah D. Hussein. « Investigation of Virulence Factors in Microbial Organisms that Associated with Public Health Risk Isolates from Different Environmental Regions ». Al-Mustansiriyah Journal of Science 33, n^o 5 (25 février 2023) : 1–7. http://dx.doi.org/10.23851/mjs.v33i5.1303.

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Infectious diseases caused by infected tools in the environments are threaten to the safety and public health. Transmission sources of these infectious diseases are unknown, but it is thought that non-living materials called fomites, are the major source of acquired infections. Three hundred and one swabs were taken from different sources and cultured on blood agar to study heamolysis ability of isolated bacteria. In this study, MacConkey agar was used to isolate Gram-negative bacteria and Sabouraud agar (SDA) to isolate fungi. The biofilm formation test was done by Congo red plate assay. 41 (13.6%) bacterial isolates were obtained and (18.27%) of fungi were isolated on Sabouraud agar (SDA). Staphylococcus aureus was the more frequent bacterial species that isolated in this study. 29% of samples showed hemolysin activity on blood agar and 32%of the isolates were biofilm- producer. Results revealed that (7.9%) of Gram-negative bacteria harbored the fimH gene, (9%) harbored the icaA were Gram-positive and 6.3 % of fungal samples had HWP1 gene. Furthermore, (9.3%) from the total samples are bacterial samples harbored hla gene belong to Staphylococcus spp. Furthermore, (5.07%) of tested samples possessed hlyA gene were Gram-negative bacteria. We found in our study that infectious organisms can be transmitted from one individual to another by fomites responsible for acquired infection.

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Msango Soko, K. R., R. C. Bhattacharya, B. Ramakrishnan, K. Sharma et S. Subramanian. « Functional characterization of bacteria isolated from different gut compartments of white grub, Anamola dimidiata, larvae ». Journal of Environmental Biology 41, n^o 6 (15 novembre 2020) : 1526–35. http://dx.doi.org/10.22438/jeb/41/6/mrn-1420.

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Aim: The aim of the present study was to isolate and characterize cellulolytic, lipolytic and nitrate reductase activities in the bacteria isolated from the gut of white grub, Anamola dimidiata larvae Methodology: Field collected third instar scarab larvae were dissected under aseptic conditions and inoculated on different bacteriological media to isolate gut bacteria. Identification of these isolates was carried out by amplifying and sequencing the 16S rRNA gene and comparing with their closest relatives in GenBank. Cellulolytic, lipolytic and nitrate reductase activities were assayed using Carbonmethyl cellulose (CMC), Rhodamine B and nitrate broth media. Results: The majority of culturable bacteria in the gut of A. dimidiata belonged to two phyla: Firmicutes (62.5%) and Proteobacteria (37.5%). Forty aerobic and eleven anaerobic bacterial strains were isolated and tested for cellulolytic, lipolytic and nitrate reductase activity, and twenty seven and thirty one cellulolytic and lipolytic gut bacteria were identified, respectively, with 19 isolates exhibiting both activities whereas ten facultative anaerobic bacteria isolates were positive for nitrate reductase activity. Interpretation: These bacterial isolates may be good sources for profiling novel isolates and enzymes for industrial use besides identifying new solutions for pest control.

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Ropiatningsuari, Nika, Suryo Wiyono et Suryahadi Suryahadi. « Skrining Bakteri Dekomposer Sebagai Penghilang Bau Kotoran Ayam ». Bumi Lestari Journal of Environment 18, n^o 1 (1 février 2018) : 19. http://dx.doi.org/10.24843/blje.2018.v18.i01.p03.

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The decomposition of chicken excreta produce odorous gases, that case environmental pollution. One of alternative technique to reduce the odorous gases is by applying specific bacteria. The aim of this study was to obtain bacterial isolates that capable of reducing NH3 and H2S production and odors. Decomposer bacterial candidates were isolated from chicken manure, guano, and peat soil. Selection of isolates of oxidizing bacteria is carried out using selective media. All isolates that were found from chicken manure, guano, and peat soil tested for hypersensitive reaction on tobacco and hemolysis on blood agar. The isolated bacteria that showed negative HR and HL responses than used for a further experiment. Five isolates of bacteria which reduce odors based on organoleptic test were WiK 15, TnK 7, WiGu 11, CGu 7 and MaGa 5. NH3 and H2S from decomposition chicken excreta were analyzed by spectrophotometric and colorimetric method. The average of total NH3 production from seven days observation showed ranged level from 1.09 ppm to 1.77 ppm, while total H2S gas production ranged from 15.05 to 16.57 ppm. Bacterial isolate CGU 7 showed make lowest total production of NH3.

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Khan, M. A., H. Satoh, T. Mino, H. Katayama, F. Kurisu et T. Matsuo. « Bacteriophage-host interaction in the enhanced biological phosphate removing activated sludge system ». Water Science and Technology 46, n^o 1-2 (1 juillet 2002) : 39–43. http://dx.doi.org/10.2166/wst.2002.0453.

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Bacteriophages were isolated from a laboratory scale enhanced biological phosphate removing (EBPR) activated sludge process, and their host range was examined. Bacterial isolates to host the bacteriophages were isolated from the EBPR activated sludge process. Bacteriophages were eluted from the EBPR activated sludge, enriched by incubation with the bacterial isolates, and then tested for plaque formation on each of the bacterial isolates. Out of 12 bacterial isolates isolated, 4 supported plaque formation. Four bacteriophages were obtained from the plaques. The host range test was conducted with the combination of the bacteriophage isolates and the bacterial isolates. Three of the bacteriophages were found to form plaques on more than one host, and one of them formed plaques on both Gram +ve and Gram −ve bacterial isolates. Two of the four bacteriophages failed to form plaques on their original bacterial host, indicating the existence of mutation on either both or one of the host and the bacteriophage. This study strongly suggests that bacteriophages are an active part of the activated sludge microbial ecosystem, having very complex interaction with their host bacteria.

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Zhang, Peipei, József Baranyi et Mark Tamplin. « Interstrain Interactions between Bacteria Isolated from Vacuum-Packaged Refrigerated Beef ». Applied and Environmental Microbiology 81, n^o 8 (6 février 2015) : 2753–61. http://dx.doi.org/10.1128/aem.03933-14.

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ABSTRACTThe formation of bacterial spoilage communities in food is influenced by both extrinsic and intrinsic environmental factors. Although many reports describe how these factors affect bacterial growth, much less is known about interactions among bacteria, which may influence community structure. This study investigated interactions among representative species of bacteria isolated from vacuum-packaged (VP) beef. Thirty-nine effectors and 20 target isolates were selected, representing 10 bacterial genera:Carnobacterium,Pseudomonas,Hafnia,Serratia,Yersinia,Rahnella,Brochothrix,Bacillus,Leuconostoc, andStaphylococcus. The influence of live effectors on growth of target isolates was measured by spot-lawn agar assay and also in liquid culture medium broth using live targets and effector cell-free supernatants. Inhibition on agar was quantified by diameter of inhibition zone and in broth by measuring detection time, growth rate, and maximum population density. A number of interactions were observed, with 28.6% of isolates inhibiting and 4.2% promoting growth. The majority ofPseudomonasisolates antagonized growth of approximately one-half of target isolates. TwoBacillusspp. each inhibited 16 targets. Among lactic acid bacteria (LAB),Carnobacterium maltaromaticuminhibited a wider range of isolates compared to other LAB. The majority of effector isolates enhancing target isolate growth were Gram-negative, includingPseudomonasspp. andEnterobacteriaceae. These findings markedly improve the understanding of potential interactions among spoilage bacteria, possibly leading to more mechanistic descriptions of bacterial community formation in VP beef and other foods.

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Majeed, Huda Zuheir, Faris Nabeeh Jaafar, Mohammed Twffeek Abdul Hussein, Ashraf Sami Hassan, Nadia Kamil Bashar et Anaam Hameed Batah. « Detection Antibiotic Resistance of Enviromental Bacterial Strains ». JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences 26, n^o 7 (15 mai 2018) : 54–62. http://dx.doi.org/10.29196/jubpas.v26i7.1372.

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Antibiotics are randomly prescribed for veterinary and human medication. Antibiotics by little number are used by human , animals are digested uncompletely in their digestive system and ended up in communal sewage and hospitals, eventually discharge in environmental water sources directly with no processing. Water itself consider as major factor of dispersal of bacteria between different environmental components. Besides, bacteria had transferable genetic mobile elements to different sites of soil, water and humans. Environmental swabs were collected locally including 50 swabs of hospital environment , 15 samples of poultry feces and chicken guts , 20 sample of heavy water and 15 sample of fish tank to identify16 isolate of Staphylococcus (4 isolate of Staphylococus aureus and 12 isolate of coagulase –ve Staphylococcus) , 19 isolate of Enterococcus spp. , 7 isolates of Pseudomonas and 5 environment isolates for each Shigella spp. and Salmonella spp. . Teicoplanin and Vancomycin sensitivity test of isolates was done , showing that 2out of 16 isolates of Staphylococcus (12.5%) were Vancomycin-resistant , and 3out of 19 isolates of Enterococcus (15.7 %) were Vancomycin-resistant, while the rest of isolates were Vancomycin- sensitive. From other side , all isolates was Teicoplanin- sensitive except only 1 Enterococcus spp. Isolate which was intermediate . The range of the Vancomycin MIC were (6-64) µg/ml . Vancomycin resistant isolates , showed that some isolates have one plasmid band after Extraction of their DNA.

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Kadhim, Shurooq Rayyis. « Detection of The Antibacterial Activity of Bacteriocin from Local Isolates of Pseudomonas fluorescens Against Gram Positive Bacteria ». Al Mustansiriyah Journal of Pharmaceutical Sciences 14, n^o 1 (1 juin 2014) : 74–78. http://dx.doi.org/10.32947/ajps.v14i1.129.

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The antibacterial activity of local isolates of Pseudomonas fluorescens (P1and P2) were tested against some pathogenic bacteria, Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, Streptococcus faecium isolated from stool urine and wounds by modified agar block method at 370C for 24 hr. The isolates of P. fluorescens were positive as producer of bacteriocin with a wide inhibition range on growth of gram positive pathogenic bacteria. P1 inhibited the bacterial growth of S. aureus isolates with a range of inhibition zone (12-20) mm. while P2 inhibited the bacterial growth with a range of inhibition zone was (13-22) mm .The range of inhibition zones of S.epidermidis by P1 were (10-18) mm. while the range by P2 was (9-20) mm. The isolate P1 inhibited the growth of all the tested isolates of S. faecalis with a range of inhibition zone between (12-19) mm. The range of inhibition zones of S. faecalis by P2 were (10-18) mm. The bacterial growth of S. faecium isolates were inhibited by P1 with a range of (15-19) mm. and (16-19) mm. with P2. Agar block method was suitable and easy for screening of bacteriocin production from this bacterium.

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Pacholak, Amanda, Wojciech Smułek, Agnieszka Zgoła-Grześkowiak et Ewa Kaczorek. « Nitrofurantoin—Microbial Degradation and Interactions with Environmental Bacterial Strains ». International Journal of Environmental Research and Public Health 16, n^o 9 (30 avril 2019) : 1526. http://dx.doi.org/10.3390/ijerph16091526.

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The continuous exposure of living organisms and microorganisms to antibiotics that have increasingly been found in various environmental compartments may be perilous. One group of antibacterial agents that have an environmental impact that has been very scarcely studied is nitrofuran derivatives. Their representative is nitrofurantoin (NFT)—a synthetic, broad-spectrum antibiotic that is often overdosed. The main aims of the study were to: (a) isolate and characterize new microbial strains that are able to grow in the presence of NFT, (b) investigate the ability of isolates to decompose NFT, and (c) study the impact of NFT on microbial cell properties. As a result, five microbial species were isolated. A 24-h contact of bacteria with NFT provoked modifications in microbial cell properties. The greatest differences were observed in Sphingobacterium thalpophilum P3d, in which a decrease in both total and inner membrane permeability (from 86.7% to 48.3% and from 0.49 to 0.42 µM min−1) as well as an increase in cell surface hydrophobicity (from 28.3% to 39.7%) were observed. Nitrofurantoin removal by selected microbial cultures ranged from 50% to 90% in 28 days, depending on the bacterial strain. Although the isolates were able to decompose the pharmaceutical, its presence significantly affected the bacterial cells. Hence, the environmental impact of NFT should be investigated to a greater extent.

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Lemenh, Yeshaneh Adimasu, Teshome Geremew Biru, Adinew Zewdu Chernet et Feleke Belachew Lema. « Isolation and identification of protease‐producing bacteria from sludge and sediment soil around Adama, Ethiopia ». Indonesian Journal of Biotechnology 26, n^o 4 (31 décembre 2021) : 159. http://dx.doi.org/10.22146/ijbiotech.63987.

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Proteases are enzymes used in industries such the production and processing of detergents, food, leather, and silk. The aim of this study was to isolate and identify protease‐producing bacteria from a sludge disposal site and from sediments. Soil samples were collected separately from the selected area. Samples weighing 1 g were serially diluted and spread onto skim milk agar. A total of 16 bacteria species were isolated from the study samples. Four bacterial isolates showed high proteolytic activity and were selected for enzymatic study based on their zone of proteolysis. The isolates were identified based on biochemical tests. The results indicated that the isolated bacteria were E. coli (99.69%), Pseudomonas putrefaciens (Shewanella putrefaciens) (91.61%), Bacillus carboniphilus (92.78%), and Lysinibacillus sphaericus (98.4%). The crude protease enzymes produced by these bacterial isolates showed promising results for application in dehairing and destaining as detergent additives. Bacillus carboniphilus showed the best level of activity and was selected as the most potent protease‐producing bacteria for both dehairing and destaining ability. Soils from sludge disposal sites and sediments from around tannery wastes could be good sources from which to isolate alkaline protease‐producing bacteria.

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Tapadar, S. A., et D. K. Jha. « Screening of zinc resistant bacteria isolated from coal mine overburden soil ». NBU Journal of Plant Sciences 7, n^o 1 (2013) : 71–76. http://dx.doi.org/10.55734/nbujps.2013.v07i01.010.

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Heavy metal pollution of coal mine spoils is a significant environmental problem affecting both flora and fauna. These degraded soils can be remediated by using heavy metal resistant microorganisms. Zinc has been usually reported in high concentration from coal mine spoils. The present study, therefore, deals with screening of Zinc, resistant bacteria isolated from coal mine spoils. The bacterial isolates were isolated from coal mine spoils of Tinsukia district of Assam. For the isolation of bacteria, King's B Medium and Pikovskaya's Agar Media were used. Heavy metal resistance of the bacterial isolates against zinc was tested on nutrient agar and sucrose-minimal salt low phosphate (SLP) medium. The results showed that out of the 20 test isolates 11 isolates were resistant. The minimum inhibitory concentration (MIC) ranged from 0.001 M to 0.02 M. Antibiotic resistance was studied for two most resistant isolates. The optimal growth conditions with reference to pH and temperature of the two most resistant bacterial isolates were evaluated. Growth pattern of the most resistant isolates was determined in different concentrations of zinc amended broth media. On the basis of cultural and biochemical characters, the resistant isolates were identified as Pseudomonas sp, Bacillus sp and Rhizobium sp. Some of these isolates also exhibited plant growth promoting (PGP) traits and phosphate solubilizing ability.

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Saryanah, N. A., Y. P. Roswanjaya, S. Himawati, Sulastri, I. S. Bidara et D. Iskandar. « Screening of plant growth-promoting bacterial endophytes and rhizobacteria isolated from Curcuma xanthorrhiza ». IOP Conference Series : Earth and Environmental Science 913, n^o 1 (1 novembre 2021) : 012022. http://dx.doi.org/10.1088/1755-1315/913/1/012022.

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Abstract Bacterial endophyte and rhizobacteria were reported to associate with medicinal plants including Zingiberaceae plants and involved in growth promotion. These beneficial bacteria are promising candidates as biostimulants because of their ability in promoting plant growth. This study aims to evaluate the activity of endophytic and rhizosphere bacteria isolated from Curcuma xanthorrhiza (Javanese turmeric) in promoting rice seedling and Javanese turmeric growth. Fifty-seven of 150 total bacterial isolates with negative hemolysis and hypersensitivity reactions were characterized to investigate their plant growth-promoting (PGP) traits. Ten selected bacteria (two bacterial endophytes and eight rhizobacteria) with multiple PGP traits were inoculated to rice seed with seed treatment and inoculated to Javanese turmeric rhizome with seed treatment and seed treatment+soil soil drenching. Our results showed that bacterial isolates tested on rice seed promoted rice seedling growth significantly. A total of five, three, six, and three bacterial isolates could increase leaf number, root length, fresh shoot weight, and fresh root weight of rice seedling (p<0.05), respectively. In contrast, all of the bacterial isolates tested on Javanese turmeric rhizomes showed a non-significant effect on the plant growth. Further studies should be considered to investigate the effect of formulated potential bacterial isolates with different application frequencies and environmental conditions on the harvest yield of rice and Javanese turmeric as well as active compounds of Javanese turmeric.

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Priyani, Nunuk. « ISOLATION AND DEGRADATION STUDY ON CARBOSULFAN CONTAINING PESTICIDE OF BIOSUFACTANT-PRODUCING BACTERIA FROM BELAWAN SUMATERA ». International Journal of Ecophysiology 2, n^o 02 (29 septembre 2020) : 92–100. http://dx.doi.org/10.32734/ijoep.v2i02.4676.

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Uncontrol use of synthetic pesticide causes environmental pollution and leaves its residue in soil and water. The objective of this research was to obtain bacterial isolates capable of producing biosurfactant from Belawan North Sumatera and to observe their biosurfactant activities as well as their potential in degrading of carbosulfan pesticide. Bacteria were isolated using selective medium, Bushnell-Hass Agar (BHA) containing 2% of pesticide with carbosulfan as the active compound. The result showed that all bacterial isolates were able to grow on the medium and consumed carbosulfan as the carbon sourc. The highest cell population was shown by isolate Sp.1 with total count was 7.6×109 CFU/ml. The highest biosurfactant activity was shown by isolate Sp.6 with the volume of emulsion was 5.627 cm3, meanwhile the highest production of biosurfactant shown by Sp.7 with concentration was 54.6 ppm. Two isolates, Sp.1 and Sp.6 were selected for further test to study their abilities in carbosulfan degradation. Both isolates were able to degrade carbosulfan completely after 21 days of incubation.

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Vaish, S., N. Garg et I. Z. Ahmad. « Bioprospecting of microbial isolates from biodynamic preparations for PGPR and biocontrol properties ». Journal of Environmental Biology 42, n^o 3 (4 mai 2021) : 644–51. http://dx.doi.org/10.22438/jeb/42/3/mrn-1529.

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Aim: To study the role of microorganisms behind their bioenhancing, biocontrol properties, their enzymatic potential, and characterization of high performing microbial isolates on molecular basis. Methodology: Dominant culturable microbes including bacteria and fungi were isolated from biodynamic preparations and screened on the basis of plant-growth promoting (PGP) activities viz., ammonia production, phosphate solubilization, siderophore production, hydrogen cyanide production, seed germination efficacy and biocontrol properties. The dominant and effective microorganisms were screened for enzymes activities viz., pectinase, cellulase and amylase. The selected bacterial and fungal isolates, exhibiting higher enzyme activities, were subjected to molecular characterization. Results: Out of 68 bacterial and 25 fungal isolates from 8 biodynamic preparations (BD 500 - BD 507), 15 bacterial isolates exhibited high plant growth promoting activities while 10 bacterial isolates exhibited biocontrol activity against pathogens. Bacillus licheniformis isolated from BD 504, expressed high pectinase (2.595 U ml-1 min-1), cellulase (0.308 U ml-1 min-1) and amylase (0.418 U ml-1 min-1) activities. Fungal isolates with high enzymatic activities, were isolated from BD 500, 503 and 506, respectively. Interpretation: Microorganism isolates from biodynamic preparations possessed strong plant growth promoting, biocontrol and enzymatic properties, which might be responsible for the efficacy of organic preparations under field conditions.

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Ronholm, J., N. Petronella, C. Chew Leung, A. W. Pightling et S. K. Banerjee. « Genomic Features of Environmental and Clinical Vibrio parahaemolyticus Isolates Lacking Recognized Virulence Factors Are Dissimilar ». Applied and Environmental Microbiology 82, n^o 4 (4 décembre 2015) : 1102–13. http://dx.doi.org/10.1128/aem.03465-15.

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ABSTRACTVibrio parahaemolyticusis a bacterial pathogen that can cause illness after the consumption or handling of contaminated seafood. The primary virulence factors associated withV. parahaemolyticusillness are thermostable direct hemolysin (TDH) and Tdh-related hemolysin (TRH). However, clinical strains lackingtdhandtrhhave recently been isolated, and these clinical isolates are poorly understood. To help understand the emergence of clinicaltdh- andtrh-negative isolates, a genomic approach was used to comprehensively compare 4 clinicaltdh- andtrh-negative isolates with 16 environmentaltdh- andtrh-negative isolates and 34 clinical isolates positive fortdhortrh, or both, with the objective of identifying genomic features that are unique to clinicaltdh- andtrh-negative isolates. The prevalence of pathogenicity islands (PAIs) common to clinical isolates was thoroughly examined in each of the clinicaltdh- andtrh-negative isolates. ThetdhPAI was not present in any clinical or environmentaltdh- andtrh-negative isolates. ThetrhPAI was not present in any environmental isolates; however, in clinicaltdh- andtrh-negative isolate 10-4238, the majority of thetrhPAI including a partialtrh1gene was present, which resulted in reclassification of this isolate as atdh-negative andtrh-positive isolate. In the other clinicaltdh- andtrh-negative isolates, neither thetrhgene nor thetrhPAI was present. We identified 862 genes in clinicaltdh- andtrh-negative isolates but not in environmentaltdh- andtrh-negative isolates. Many of these genes are highly homologous to genes found in common enteric bacteria and included genes encoding a number of chemotaxis proteins and a novel putative type VI secretion system (T6SS) effector and immunity protein (T6SS1). The availability of genome sequences from clinicalV. parahaemolyticustdh- andtrh-negative isolates and the comparative analysis may help provide an understanding of how this pathotype is able to survivein vivoduring clinical illness.

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Nwankwo, IU, KC Edward et CG Udensi. « A Case Study on Antimicrobial Resistance of Bacterial Isolates From High-Touched Surfaces in Hospitals in Madonna Catholic Hospital, Abia State ». Stamford Journal of Microbiology 12, n^o 1 (20 décembre 2022) : 1–7. http://dx.doi.org/10.3329/sjm.v12i1.63336.

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When healthcare professionals handle infected materials with their hands and gloves or when patients come into contact with contaminated surfaces directly, environmental contamination enhances the transmission of bacteria. This study aimed to determine the antimicrobial resistance of bacteria isolated from high-touched surfaces in Madonna Catholic hospital, Abia State. Samples of the most commonly contacted surfaces were gathered by rubbing and spinning sterile swabs sticks with normal saline on the surfaces. Direct inoculation of the swab samples using the streak plate method was done on Blood agar and MacConkey agar plates. The serial dilution method enumerated the bacterial species associated with the contact surfaces. The bacterial isolates were subjected to an antibiotic susceptibility test using the Kirby Bauer disc diffusion technique. This study showed that thirty-six (36) bacteria isolates were obtained from fifty (50) swab samples collected from high-touched surfaces. It was also observed that Staphylococcus aureus is the most frequently occurring isolate with 12 (33.3%), followed by coagulase- negative Staphylococci 10 (27.8%). The least occurring isolate was recorded for Pseudomonas spp. 5 (13.9%). It was recorded in this study that door handles showed the highest distribution of bacterial isolates 14 (38.8%), whereas swab samples obtained from the benches showed a minor distribution 2 (5.5%). However, the antibiotics susceptibility profile of bacterial isolate from the sampled surfaces showed that Ciprofloxacin was the most effective antibiotic tested at a rate of 100%. It was revealed in this study that most of the bacterial isolates showed a highest level of resistance to Chloramphenicol, Tetracycline and Ampiclox (100%). An appreciable number of pathogenic bacteria isolates were detected in the frequently touched surfaces in the hospital. The presence of these organisms could be the leading cause of hospital-acquired infections. Suitable hygienic measures must be adopted at the hospital to reduce the level of contamination and spread of disease through these surfaces. It is also vital to promote excellent personal hygiene like hand washing. This study finding suggests that ciprofloxacin can be used for treatment and control bacterial infections. Stamford Journal of Microbiology, Vol.12 (1) 2022: 1-7

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Ibraheem, Khalida Jhalil. « Antimicrobial Activity of Extracts Bacillus Species Isolated From Baghdad Soil Against Some Human Pathogenic Microorganisms ». Al Mustansiriyah Journal of Pharmaceutical Sciences 16, n^o 2 (1 décembre 2016) : 82–87. http://dx.doi.org/10.32947/ajps.v16i2.114.

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Bacillus species are the predominant soil bacteria because of their resistant endospore formation and can produce many different antimicrobial substances. The main aim of this study was to isolate Bacillus species from soil and investigate their antimicrobial activity against some pathogenic bacteria and fungi isolated from human. 48 soil samples were collected from different region of Baghdad city (Rashidiya, Mahmudiyah, Alkraat and Aldora) during December 2015 and analyzed for the presence of Bacillus species. Bacterial isolates were identified by using different microscopical examination, cultural characteristics, biochemical tests and confirmed by VITEK 2 bacterial identification system. The antimicrobial effects of Bacillus species extracts against some pathogenic bacteria (Gram-positive, Gram-negative) and fungi were examined. The identified Bacillus species included B. polymyxa, B. cereus, B. licheniformis, B. mycoides, B. firmus and B. subtilis. The results indicate that the bacterial isolates showed antimicrobial activity against all tested pathogenic bacteria and fungi. B. polymyxa showed best activity against most test organisms compare to other Bacillus isolates, follow by B. subtilis, B. cereus, B. licheniformis, B. firmus and B. mycoides. This study reveals that some Bacillus species have the ability to produce antimicrobial compounds that can be used to control microbial infections in future.

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Al-Charrakh, Alaa Hani. « Frequency and antimicrobial resistance of bacteria isolated from oral and topical medicaments from Hilla, Iraq ». Journal of Infection in Developing Countries 6, n^o 06 (26 mars 2012) : 489–94. http://dx.doi.org/10.3855/jidc.1817.

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Introduction: The presence of microorganisms in pharmaceuticals is undesirable because they may cause spoilage of the product and may present an infection hazard to the consumers or patients. Methodology: A total of 102 samples of oral and topical non-sterile pharmaceutical products were collected at random from different drug houses and pharmacies in Iraq, to investigate the microbial contamination of these products. Bacterial isolates recovered from these medicaments were subjected to susceptibility testing against various antibiotics by disk diffusion method according to Clinical and Laboratory Standards (CLSI) guidelines. Results: The results revealed that the occurrence of Gram-positive bacteria was in oral and topical medicaments while Gram-negative bacteria were only detected in topical medicaments. More than 58% of Bacillus isolates were resistant to lincomycin and Bacillus mycoides isolates were resistant to beta-lactam antibiotics and trimethoprim-sulfamethoxazole. Staphylococcus spp. showed a relatively high resistance to ampicillin, amoxicillin, penicillin, tetracycline, and trimethoprim-sulfamethoxazole. S. epidermidis had the highest number of multi-resistant isolates. Furthermore, 87.5% of isolated Gram-negative rods showed high resistance to beta-lactam antibiotics and 75% of them were highly resistant to erythromycin. One isolate of Pseudomonas aeruginosa was the most resistant among all Gram-negative rod isolates. Conclusion: The high rate of resistance to antimicrobial agents of bacterial isolates recovered from oral and topical medicaments in this study may indicate a widespread antibiotic resistance among bacteria isolated from different sources, including those of anthropological and environmental origin.

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Casas, Veronica, Joseph Magbanua, Gerico Sobrepeña, Scott T. Kelley et Stanley R. Maloy. « Reservoir of Bacterial Exotoxin Genes in the Environment ». International Journal of Microbiology 2010 (2010) : 1–10. http://dx.doi.org/10.1155/2010/754368.

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Many bacteria produce secreted virulence factors called exotoxins. Exotoxins are often encoded by mobile genetic elements, including bacteriophage (phage). Phage can transfer genetic information to the bacteria they infect. When a phage transfers virulence genes to an avirulent bacterium, the bacterium can acquire the ability to cause disease. It is important to understand the role played by the phage that carry these genes in the evolution of pathogens. This is the first report of an environmental reservoir of a bacterial exotoxin gene in an atypical host. Screening bacterial isolates from the environment via PCR identified an isolate with a DNA sequence >95% identical to theStaphylococcus aureusenterotoxin A gene (sea). 16S DNA sequence comparisons and growth studies identified the environmental isolate as a psychrophilicPseudomonasspp. The results indicate that theseagene is present in an alternative bacterial host, providing the first evidence for an environmental pool of exotoxin genes in bacteria.

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Chiang, Sarah M., Tao Dong, Thomas A. Edge et Herb E. Schellhorn. « Phenotypic Diversity Caused by Differential RpoS Activity among Environmental Escherichia coli Isolates ». Applied and Environmental Microbiology 77, n^o 22 (23 septembre 2011) : 7915–23. http://dx.doi.org/10.1128/aem.05274-11.

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ABSTRACTEnteric bacteria deposited into the environment by animal hosts are subject to diverse selective pressures. These pressures may act on phenotypic differences in bacterial populations and select adaptive mutations for survival in stress. As a model to study phenotypic diversity in environmental bacteria, we examined mutations of the stress response sigma factor, RpoS, in environmentalEscherichia coliisolates. A total of 2,040 isolates from urban beaches and nearby fecal pollution sources on Lake Ontario (Canada) were screened for RpoS function by examining growth on succinate and catalase activity, two RpoS-dependent phenotypes. TherpoSsequence was determined for 45 isolates, including all candidate RpoS mutants, and of these, six isolates were confirmed as mutants with the complete loss of RpoS function. Similarly to laboratory strains, the RpoS expression of these environmental isolates was stationary phase dependent. However, the expression of RpoS regulon members KatE and AppA had differing levels of expression in several environmental isolates compared to those in laboratory strains. Furthermore, after platingrpoS+isolates on succinate, RpoS mutants could be readily selected from environmentalE. coli. Naturally isolated and succinate-selected RpoS mutants had lower generation times on poor carbon sources and lower stress resistance than theirrpoS+isogenic parental strains. These results show that RpoS mutants are present in the environment (with a frequency of 0.003 among isolates) and that, similarly to laboratory and pathogenic strains, growth on poor carbon sources selects forrpoSmutations in environmentalE. coli. RpoS selection may be an important determinant of phenotypic diversification and, hence, the survival ofE. coliin the environment.

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Sen, Swagata, et Mihir Lal Saha. « Bacteria Associated With the Leafy Salad Vegetables Of Old Dhaka City and Their Multiple Antibiotic Resistance (Mar) Index ». Dhaka University Journal of Biological Sciences 31, n^o 2 (2 février 2023) : 361–69. http://dx.doi.org/10.3329/dujbs.v31i2.60893.

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The present work aimed to evaluate the bacteria associated with the most popular leafy salad vegetables like Coriander, Mint, and Lettuce and their antibiotic resistance pattern. Samples were collected from Rayshaheb Bazar, Nazira Bazar, and Shyam Bazar during June-August 2019. The maximum bacterial load was found in Coriander and the minimum bacterial load was in Mint. A total of 149 colonies were isolated and 35 isolates were selected for Culture and Sensitivity test against 15 common antibiotics like Amoxicillin (Ax), Cefixime (CFM), Levofloxacin (Lev), Clarithromycin (CLR), Ceftriaxone (CRO), Neomycin (N), Kanamycin (K), Ciprofloxacin (Cip), Erythromycin (E), Doxycycline (Do), Vancomycin (VA), Cefuroxime (CXM), Chloramphenicol (C), Rifampicin (RA), and Gentamycin (CN). Sixteen antibiotic resistant bacterial isolates were selected for their identification and drug resistance pattern. Among these 15 antibiotic resistant bacterial isolates, only 2 were Gram positive and were identified as Enterococcus faecalis and the Gram negative bacteria belonged to the genus Enterobacter (9), Serratia (3), Klebsiella (2).The drug resistance pattern showed that most of the isolated bacteria were resistant against Amoxicillin and susceptible to Chloramphenicol. The (multiple antibiotic resistance (MAR) inedx of the isolated bacteria ranged between 33.33% and 86.67% which is very alarming. Dhaka Univ. J. Biol. Sci. 31(2): 361-369, 2022 (July)

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Biyela, P. T., J. Lin et C. C. Bezuidenhout. « The role of aquatic ecosystems as reservoirs of antibiotic resistant bacteria and antibiotic resistance genes ». Water Science and Technology 50, n^o 1 (1 juillet 2004) : 45–50. http://dx.doi.org/10.2166/wst.2004.0014.

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The widespread and indiscriminate use of antibiotics has led to the development of antibiotic resistance in pathogenic, as well as commensal, microorganisms. Resistance genes may be horizontally or vertically transferred between bacterial communities in the environment. The recipient bacterial communities may then act as a reservoir of these resistance genes. In this study, we report the incidence of antibiotic resistance in enteric bacteria isolated from the Mhlathuze River and the distribution of genetic elements that may be responsible for the observed antibiotic resistance. The resistance of the enteric bacteria isolated over a period of one year showed that resistance to the older classes of antibiotics was high (94.7% resistance to one antibiotic and 80.8% resistance to two antibiotics). Furthermore, antibiotic resistance data of the environmental isolates showed a strong correlation (r = 0.97) with data obtained from diarrhoea patients. PCR based methods demonstrated that class 1 integrons were present in >50% of the environmental bacterial isolates that were resistant to multiple antibiotics. This class of integrons is capable of transferring genes responsible for resistance to b-lactam, aminoglycoside, sulfonamide and quaternary ammonium antimicrobial agents. Conjugate plasmids were also isolated, but from a small percentage of isolates. This study showed that the Mhlathuze River (a) is a medium for the spread of bacterial antibiotic resistance genes, (b) acts as a reservoir for these genes and (c) due to socio-economic pressures, may play a role in the development and evolution of these genes along this river system.

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Çandiroğlu, Begüm, et Nihal Doğruöz Güngör. « The Biotechnological Potentials of Bacteria Isolated from Parsık Cave, Turkey : Measuring the enzyme profiles, antibiotic resistance and antimicrobial activity in bacteria ». Johnson Matthey Technology Review 64, n^o 4 (1 octobre 2020) : 466–79. http://dx.doi.org/10.1595/205651320x15923194903811.

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Since cave ecosystems have extraordinary environmental conditions, these ecosystems offer opportunities for microbiological studies. In this study, cultivable bacteria isolated from Parsık cave, Turkey, were investigated regarding enzyme profiles, antibiotic resistance and potential for production of antimicrobial agents. The metabolic properties of 321 bacterial isolates were determined. The most produced enzyme by the isolates was found to be tyrosine arylamidase. The enzymatic reactions of the bacteria showed that Parsık cave isolates have high aminopeptidase activity. The highest antibiotic resistance frequency of the isolates was 38.6% against ampicillin. While the isolates displayed variable inhibition rates against tested pathogenic microorganisms, they showed the highest inhibition against Candida albicans. The results show that the bacteria isolated from Parsık cave have potential for further studies related to biotechnological applications. The study findings contribute increased knowledge on metabolic peculiarities of bacteria isolated from cave ecosystems.

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Acevedo-Barrios, Rosa, Angela Bertel-Sevilla, Jose Alonso-Molina et Jesus Olivero-Verbel. « Perchlorate-Reducing Bacteria from Hypersaline Soils of the Colombian Caribbean ». International Journal of Microbiology 2019 (17 février 2019) : 1–13. http://dx.doi.org/10.1155/2019/6981865.

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Perchlorate (ClO4−) has several industrial applications and is frequently detected in environmental matrices at relevant concentrations to human health. Currently, perchlorate-degrading bacteria are promising strategies for bioremediation in polluted sites. The aim of this study was to isolate and characterize halophilic bacteria with the potential for perchlorate reduction. Ten bacterial strains were isolated from soils of Galerazamba-Bolivar, Manaure-Guajira, and Salamanca Island-Magdalena, Colombia. Isolates grew at concentrations up to 30% sodium chloride. The isolates tolerated pH variations ranging from 6.5 to 12.0 and perchlorate concentrations up to 10000 mg/L. Perchlorate was degraded by these bacteria on percentages between 25 and 10. 16S rRNA gene sequence analysis indicated that the strains were phylogenetically related toVibrio,Bacillus,Salinovibrio,Staphylococcus, andNesiotobactergenera. In conclusion, halophilic-isolated bacteria from hypersaline soils of the Colombian Caribbean are promising resources for the bioremediation of perchlorate contamination.

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Fardami, Aminu Yusuf, Abdullahi Hassan Kawo, Sani Yahaya, Maryam Lami Riskuwa-Shehu, Ibrahim Lawal et Haruna Yahaya Ismail. « Isolation and Screening of Biosurfactant-producing Bacteria from Hydrocarbon-contaminated Soil in Kano Metropolis, Nigeria ». Journal of Biochemistry, Microbiology and Biotechnology 10, n^o 1 (31 juillet 2022) : 52–57. http://dx.doi.org/10.54987/jobimb.v10i1.664.

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Biosurfactants are surface-active biomolecules produced by microorganisms that have different applications in solving many environmental problems. This study was carried out to screen biosurfactant-producing bacteria isolated from hydrocarbon-contaminated soil of Kano Metropolis, Kano State- Nigeria. Soil samples were collected and processed. Biosurfactant-producing bacteria were enumerated, isolated and characterized using cultural, morphological and biochemical characteristics. Blood haemolysis, oil drop collapse and oil displacement tests were employed for the screening of the bacterial isolates for the potential to produce biosurfactant. The viable aerobic heterotrophic bacterial count of the samples ranges from 1.0 to 8.4×106 cfu/g. Eight bacterial genera were biochemically identified as Pseudomonas aeruginosa, Enterobacter cloacae, Pantoea agglomerans, Pseudomonas sp., Bacillus subtilis, Enterobacter alvei, Bacillus sp. and Klebsiella sp. Bacillus subtilis had the highest frequency of occurrence of 5(27%) while Bacillus sp. and Enterobacter alvei have the least occurrences of 1(6%) each. The eight identified bacterial isolates were all positive for the haemolysis test, drop collapse and oil displacement test.

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Udoekong, Nsikan Samuel, Bassey Enya Bassey, Anne E. Asuquo, Otobong Donald Akan et Casmir Ifeanyichukwu Cajetan Ifeanyi. « Multi-Drug Resistance Genes associated with Some Gram-Negative Bacterial Isolated from Shellfish in Iko and Douglas River Estuaries in Nigeria ». European Journal of Biology and Biotechnology 2, n^o 3 (26 mai 2021) : 19–27. http://dx.doi.org/10.24018/ejbio.2021.2.3.191.

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Background: Multi drug resistant bacterial agents that contaminate seafood cause several diseases in humans and are widely documented as a global public health challenge. Methods: This study evaluated the microbiological and antimicrobial resistance genes profiles of bacterial Isolates from shellfish vended at Iko and Douglas Creeks of Cross River State, Nigeria. A total of 540 shellfish (117 clams, 88 oysters, 136 periwinkles) samples were collected from various vendor at the two Creeks were analyzed. The samples were processed using standard microbiological methods to identify bacterial pathogens. Antimicrobial susceptibility was assayed using the Kirby-Bauer disk diffusion method. Isolates were screened for antimicrobial resistant genes using polymerase chain reaction. Results: Overall, a total of 135 bacteria isolates were identified. The most common isolate was Alcaligenes species 53(39.2%) followed by Pseudomonas species 44(32.6%), Providencia species 25(18.5%), Vibrio species 6(4.4%), and Paenalcaligenes species 7(5.2%). The isolates showed varying susceptibilities to Imipenem (36%) and amikacin (28%) but were all resistant to Trimethoprim-Sulfamethoxazole. Fifty-three isolates had a multiple antibiotic resistance index (MARI) of ≥0.9 - 1.0. Most of the bacterial isolates were detected with TEM genes (82.2%), SHV (51.8%,), VIM (50.3%) resistance genes. None of the isolates expressed Veb gene. Only 40.7% of the isolates expressed QnrB gene while none expressed QnrA and QnrS. Conclusion: The detection of these multidrug resistant clinically relevant bacterial species suggests a significant linkage of commonly consumed seafood in the community and environmental spread of MDR bacteria.

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Elamary, Rokaia, et Wesam M. Salem. « Optimizing and purifying extracellular amylase from soil bacteria to inhibit clinical biofilm-forming bacteria ». PeerJ 8 (2 novembre 2020) : e10288. http://dx.doi.org/10.7717/peerj.10288.

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Background Bacterial biofilms have become a major threat to human health. The objective of this study was to isolate amylase-producing bacteria from soil to determine the overall inhibition of certain pathogenic bacterial biofilms. Methods We used serial dilution and the streaking method to obtain a total of 75 positive amylase isolates. The starch-agar plate method was used to screen the amylolytic activities of these isolates, and we used morphological and biochemical methods to characterize the isolates. Optimal conditions for amylase production and purification using Sephadex G-200 and SDS-PAGE were monitored. We screened these isolates’ antagonistic activities and the purified amylase against pathogenic and multi-drug-resistant human bacteria using the agar disk diffusion method. Some standard antibiotics were controlled according to their degree of sensitivity. Finally, we used spectrophotometric methods to screen the antibiofilm 24 and 48 h after application of filtering and purifying enzymes in order to determine its efficacy at human pathogenic bacteria. Results The isolated Bacillus species were Bacillus megaterium (26.7%), Bacillus subtilis (16%), Bacillus cereus (13.3%), Bacillus thuringiesis (10.7%), Bacillus lentus (10.7%), Bacillus mycoides (5.3%), Bacillus alvei (5.3%), Bacillus polymyxa (4%), Bacillus circulans (4%), and Micrococcus roseus (4%). Interestingly, all isolates showed a high antagonism to target pathogens. B. alevi had the highest recorded activity (48 mm) and B. polymyxa had the lowest recorded activity (12 mm) against Staphylococcus aureus (MRSA) and Escherichia coli, respectively. On the other hand, we detected no antibacterial activity for purified amylase. The supernatant of the isolated amylase-producing bacteria and its purified amylase showed significant inhibition for biofilm: 93.7% and 78.8%, respectively. This suggests that supernatant and purified amylase may be effective for clinical and environmental biofilm control. Discussion Our results showed that soil bacterial isolates such as Bacillus sp. supernatant and its purified amylase are good antibiofilm tools that can inhibit multidrug-resistant former strains. They could be beneficial for pharmaceutical use. While purified amylase was effective as an antibiofilm, the isolated supernatant showed better results.

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Bokhari, Shazia, Roheela Yasmeen, Aisha Waheed Qurashi, Samiya Habib et Uzma Rafi. « Isolation of Keratinolytic from Chicken (Gallus gallus domesticus) Farms and Assessment of their Efficacy in Feathers Degradation ». Vol 3 Issue 4 3, n^o 4 (23 décembre 2021) : 142–51. http://dx.doi.org/10.33411/ijist/2021030401.

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Keratinolytic microorganisms and their enzymes are associated with poultry feather degradation. In the present study feathers of Gallus gallus domesticus (chicken) and surrounding dry soil was collected from a private poultry sheds located in Jahman village near Lahore. Bacteria were isolated by using enrichment techniques and screened for their proteolytic activity on skim agar. Isolated Bacteria were colonially, morphologically and biochemically characterized and named as SNC1, SNC2, SNC3, SNC4, SCH1, SCH2, SCH3 and SCH4. Results showed closed similarity of bacterial isolates with bacillus species. Effect of various media (LB-broth and Nutrient broth), pHs (7 and 8) and temperatures (4, 37, and 50℃) were recorded on bacterial growth and feather degradation. Bacterial cell densities and amount of keratin produced per gram feather weight were high at temperature 50℃ and pH 8.0. The feather degradation by bacterial isolates was confirmed at different time intervals using stereomicroscopes. The protein analysis of G. gallus domesticus feathers showed protein contents of 3.125g/100 ml. It was concluded high temperature and alkaline pH favored keratin production by bacterial consortia. Moreover, the bacterial isolates used in the current study have the potential to degrade poultry feather waste and extracted keratin is found to be promising for further exploitation of poultry waste.

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Anzum, Nafisa, Farhana Islam Khan, Mohammad Zabed Hossain, Mohammad Nurul Islam et Mihir Lal Saha. « Isolation and Identification of Pigment Producing Bacteria From the Ratargul Swamp Forest Soil ». Dhaka University Journal of Biological Sciences 31, n^o 1 (10 février 2022) : 1–8. http://dx.doi.org/10.3329/dujbs.v31i1.57911.

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Pigments are one of the most significant secondary metabolites produced by microorganisms. The aim of the present study was to isolate and identify pigmentproducing bacteria from the Ratargul Swamp Forest (RSF) soil, which is the one and only fresh water swamp forest of Bangladesh. Soil samples were randomly collected from 10 different quadrates (10 m x 10 m) of RSF. The pH values of the soil samples were found to be strongly acidic and ranged between 4.71 and 5.48. Bacterial load of the samples ranged from 1.33×105 to 1.93×108 cfu/g, 6.05×106 to 9.07×107 cfu/g and from 1.16×107 to 1.61×108 cfu/g on nutrient agar (NA), peptone yeast-extract glucose (PYG) agar and Luria-Bertani (LB) agar media, respectively. Interestingly, both the highest and lowest bacterial counts were observed on NA, which was 1.93×108 cfu/g and 1.33×105 cfu/g, respectively. The isolates were found to produce various pigments like yellow, red, dark orange and sweet pink during their colony developments. A total of 71 bacterial isolates were obtained of which 11 were subjected to further study. All the selected bacteria were found to be rod shaped. Out of the 11 isolates, 9 were Gram-positive and 2 were Gramnegative. Provisionally identified potential pigment producing eight bacterial isolates were identified by using molecular marker. Seven of them were matched with their conventional identification up to generic level but conventionally identified Erwinia stewartii was found to be as Aeromonas sobria. Among the 11 isolates, 8 could produce three different types of pigments namely red, yellow and dark orange during in vitro pigment production. The isolated pigment producing bacteria could be used for better biotechnological application. Dhaka Univ. J. Biol. Sci. 31(1): 1-8, 2022 (January)

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Obuekwe, I. S., et C. K. Offodile. « ANTIBIOTIC RESISTANCE IN BACTERIAL PATHOGENS ISOLATED FROM CATTLE DUNG AND ITS CONTAMINATED SOIL ». African Journal of Health, Safety and Environment 1, n^o 2 (9 novembre 2020) : 66–83. http://dx.doi.org/10.52417/ajhse.v1i2.85.

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Cattle dung is used as organic fertilizer and alternative source of fuel or biogas but could also be a source of antibiotic resistance genes in the environment. This study isolated, identified and assessed antibiotic susceptibility pattern of bacteria from cattle dung and its contaminated soil. Bacteria isolation and identification were based on standard techniques while hemolytic activity was used to confirm potential pathogenic bacteria. Antibiotic susceptibility pattern of isolated pathogens were assayed by disk diffusion method. Among isolated bacteria, Staphylococcus spp had highest occurrence of 23.8 % while Micrococcus spp was the least at 1.3 %. Hemolytic bacteria isolates were Staphylococcus aureus (16.5 %), Bacillus spp (17.4 %), Nocardia spp (4.6 %), Escherichia coli (29.4 %), Pseudomonas spp (13.8 %), Serratia marcersens (2.8 %) and Salmonella spp (15.6 %). High resistance (100 %) against Ampiclox (30 µg) was observed in all Staphylococcus aureus and Bacillus spp isolates while Pseudomonas aeruginosa isolates showed 100 % resistance to Ofloxacin (30 µg). Most Gram-positive bacterial isolates were majorly resistant to Beta lactams while Gram negative bacteria were resistant to Fluoroquinolones antibiotics. Multiple antibiotics resistant index (MARI) was measured at greater than 0.2, and was observed in 71.5 % of the hemolytic pathogens. Antibiotics resistance in hemolytic bacterial pathogens from this study is indicative of environmental sources of antibiotic resistance and possible adverse effects on human health.

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Tormoehlen, Kristin, Yvette J. Johnson-Walker, Emily W. Lankau, Maung San Myint et John A. Herrmann. « Considerations for studying transmission of antimicrobial resistant enteric bacteria between wild birds and the environment on intensive dairy and beef cattle operations ». PeerJ 7 (27 février 2019) : e6460. http://dx.doi.org/10.7717/peerj.6460.

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Background Wild birds using livestock facilities for food and shelter may contribute to dissemination of enteric pathogens or antimicrobial resistant bacteria. However, drivers of microbial exchange among wildlife and livestock are not well characterized. Predisposition for acquiring and retaining environmental bacteria may vary among species because of physiologic or behavioral differences, complicating selection of a bacterial model that can accurately characterize microbial connections among hosts of interest. This study compares the prevalence and antibiotic resistance phenotypes of two potential model bacterial organisms isolated from wild birds and their environments. Methods We compared prevalence and resistance profiles of Escherichia coli and Enterococcus species isolated from environmental swabs and bird feces on a residential control site, a confinement dairy, a pasture-based beef farm, and a confinement beef farm. Results Bird feces at all sites had low-to-moderate prevalence of Escherichia coli (range: 17–47%), despite potential for exposure on farms (range: 63–97%). Few Escherichia coli were isolated from the control environment. Enterococcus faecalis was dominant in birds at both beef farms (62% and 81% of Enterococcus isolates) and low-to-moderately prevalent at the dairy and control sites (29% and 23% of isolates, respectively). Antimicrobial resistance prevalence was higher in farm samples compared to those from the residential control, but distribution of resistant isolates varied between the bacterial genera. Birds on all farms carried resistant Enterococcus at similar rates to that of the environment, but resistance was less common in bird-associated Escherichia coli despite presence of resistant isolates in the farm environment. Discussion Bacterial species studied may affect how readily bacterial exchange among populations is detected. Selection of microbial models must carefully consider both the questions being posed and how findings might influence resulting management decisions.

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Qurashi, Waheed, Tayyaba Abbas Bajwa, Hira Hashim, Fizza Atta et Sumayyah Malik. « Rhizosphere Bacteria with the Potential of Forming Biofilm and Plant Growth Promotion Under Salt Stress ». Lahore Garrison University Journal of Life Sciences 2, n^o 2 (22 avril 2020) : 103–13. http://dx.doi.org/10.54692/lgujls.2018.020223.

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Bacteria develop microbial communities as biofilm under different environmental stress factors like salinity, temperature, pH and antimicrobial agents and help in the adherence of bacteria to different surfaces. The growth of microorganisms is inhibited in the presence of salinity. An objective of the present research work was to check the growth response and biofilm behavior of indigenous bacteria isolated from plant rhizosphere in the presence of salt. Bacterial strains were named as TAK, TAF and SY. Biofilm formation response was also observed at different molar concentration (0M, 1M, 2M and 3M) of NaCl following test tube assay after 24, 48 and 72 hours of culture incubation. Results showed that TAK has the best biofilm forming ability on abiotic surface as compared to isolate TAF and SY, however, isolate SY showed growth and form biofilm under saline conditions. Bacterial plant growth promoting response was also determined on the basis of improvement in seed germination, shoot length and root length. In general, bacterial biofilm was best at 1M to 3M NaCl stress and 72 hours of culture incubation . Inoculation with SY improved (shoot length 3 % and root length 10.41 %) at 100 mM when compared to inoculated seedlings at 0 mM NaCl stress. It was concluded that among all three isolates, isolate SY used for broad perspective to increase soil fertility. While working to strive for the most promising isolates involved in plant growth promotion, the indigenous isolates showed the promising ability to improve germination of seeds in saline soil while helping the seeds to grow in salt stress conditions.

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Schmitz-Esser, Stephan, Elena R. Toenshoff, Susanne Haider, Eva Heinz, Verena M. Hoenninger, Michael Wagner et Matthias Horn. « Diversity of Bacterial Endosymbionts of Environmental Acanthamoeba Isolates ». Applied and Environmental Microbiology 74, n^o 18 (18 juillet 2008) : 5822–31. http://dx.doi.org/10.1128/aem.01093-08.

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ABSTRACT Free-living amoebae are frequent hosts for bacterial endosymbionts. In this study, the symbionts of eight novel environmental Acanthamoeba strains isolated from different locations worldwide were characterized. Phylogenetic analysis revealed that they were related to one of four evolutionary lineages of amoeba symbionts recognized previously. This study provides evidence for the existence of only a small number of phylogenetically well-separated groups of obligate intracellular endosymbionts of acanthamoebae with global distribution.

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Nweke, Christian. « Kinetics of zinc toxicity to environmental bacterial isolates ». Ambiente e Agua - An Interdisciplinary Journal of Applied Science 4, n^o 3 (31 décembre 2009) : 23–34. http://dx.doi.org/10.4136/ambi-agua.100.

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Alotaibi, Fahad, Soon-Jae Lee, Marc St-Arnaud et Mohamed Hijri. « Salix purpurea and Eleocharis obtusa Rhizospheres Harbor a Diverse Rhizospheric Bacterial Community Characterized by Hydrocarbons Degradation Potentials and Plant Growth-Promoting Properties ». Plants 10, n^o 10 (23 septembre 2021) : 1987. http://dx.doi.org/10.3390/plants10101987.

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Phytoremediation, a method of phytomanagement using the plant holobiont to clean up polluted soils, is particularly effective for degrading organic pollutants. However, the respective contributions of host plants and their associated microbiota within the holobiont to the efficiency of phytoremediation is poorly understood. The identification of plant-associated bacteria capable of efficiently utilizing these compounds as a carbon source while stimulating plant-growth is a keystone for phytomanagement engineering. In this study, we sampled the rhizosphere and the surrounding bulk soil of Salixpurpurea and Eleocharis obusta from the site of a former petrochemical plant in Varennes, QC, Canada. Our objectives were to: (i) isolate and identify indigenous bacteria inhabiting these biotopes; (ii) assess the ability of isolated bacteria to utilize alkanes and polycyclic aromatic hydrocarbons (PAHS) as the sole carbon source, and (iii) determine the plant growth-promoting (PGP) potential of the isolates using five key traits. A total of 438 morphologically different bacterial isolates were obtained, purified, preserved and identified through PCR and 16S rRNA gene sequencing. Identified isolates represent 62 genera. Approximately, 32% of bacterial isolates were able to utilize all five different hydrocarbons compounds. Additionally, 5% of tested isolates belonging to genera Pseudomonas, Acinetobacter, Serratia, Klebsiella, Microbacterium, Bacillus and Stenotrophomonas possessed all five of the tested PGP functional traits. This culture collection of diverse, petroleum-hydrocarbon degrading bacteria, with multiple PGP traits, represents a valuable resource for future use in environmental bio- and phyto-technology applications.

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Rahman, Arafat, Manawar Sultana, Md Aftab Uddin, M. A. Malek et M. Anwer Hossain. « Silkworm as an animal infection model for the screening of environmental, clinical and veterinary pathogens ». Bangladesh Medical Research Council Bulletin 41, n^o 2 (18 octobre 2016) : 73–80. http://dx.doi.org/10.3329/bmrcb.v41i2.29985.

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Silkworm, Bombyx mori, has passive immunity and can be infected by pathogenic bacteria. Therefore, it can be used as a robust bacterial infection model for screening of pathogenic isolates from various sources. In this work, 11 environmental, clinical and veterinary isolates were screened for pathogenicity using silkworm larvae by injecting bacterial suspension through their dorsal surface and observing response. Experimental conditions were established by using Bacillus thuringiensis SW_R_F_1, Escherichia coli O157:H7, E. coli DH5? and 0.6% saline. Nine out of 11 isolates were detected pathogenic after screening. The biochemical and genomic analysis of the nine test isolates confirmed their pathogenicity. The LD50 of Pseudomonas aeruginosa 47D and Salmonella Typhimurium 77 were 4.63×107 at 12 hours was 8.02×107 cells/100?l/gram at 24 hours respectively. These results indicated that silkworm exhibits differential pathological response for pathogenic and nonpathogenic bacteria, and can be used as an alternative to animal model for screening diverse isolates.

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Widyananto, P. A., S. I. Muchlissin, O. K. Radjasa et A. Sabdono. « Aliphatic polyester biodegradation by coral-associated bacteria from Karimunjawa Marine National Park, Java Sea ». IOP Conference Series : Earth and Environmental Science 967, n^o 1 (1 janvier 2022) : 012045. http://dx.doi.org/10.1088/1755-1315/967/1/012045.

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Abstract Plastic waste is one of the environmental pollutants that is difficult to degrade. The spread of plastic waste is almost everywhere even in the ocean, especially in coral reef ecosystem. Non-degradable plastic like polyethylene, polypropylene, and polystyrene begins to be partially replaced with biodegradable plastic materials (i.e polycaprolactone) as a strategy to reduce non-degradable polymer materials. Hence, this study aims is to find the potential of polycaprolactone biodegradation from coral associated-bacteria from Karimunjawa National Park. Coral samples were isolated in July 2020 from areas with influence by anthropogenic. Bacterial isolates were screened using tributyrin and polycaprolactone as substrates to reveal potential polyester degradation enzymes. The result obtained only one active bacterial isolate that potential to degrade polycaprolactone from a total of 18 isolates bacteria. LBB 2 showed that strain can degrade polycaprolactone by 8 days incubation period with 4 days in room temperature and 4 days in a 4°C incubation room. Bacterial identification by 16S rRNA sequences showed that strain LBB 2 refers to the bacteria Bacillus subtilis. The similarity level in the database of National Center Biotechnology Information by 99.45%. These results prove that associated bacteria from stony coral might play a role in degrading aliphatic polyesters.

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Suhartono, Suhartono, Yekki Yasmin et Nur Azizah. « Biopotensi Bakteri Entomopatogen Isolat Lokal sebagai Pengendali Hayati Larva Helicoverpa armigera (Hübner) ». Jurnal Ilmu Pertanian Indonesia 27, n^o 2 (13 avril 2022) : 182–90. http://dx.doi.org/10.18343/jipi.27.2.182.

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The use of insecticides in the intensive control of Helicoverpa armigera caterpillars increases the environmental deterioration, the natural enemies, and threatening the user's health. The study aims to isolate, characterize, and determine the biological potential of local isolates of entomopathogen bacteria as the biological controlling agent on H. armigera larvae. Bacterial isolation was performed using a serial dilution followed by bacterial macroscopic and microscopic characterizations. A total of eight entomopathogen bacterial isolates were successfully obtained from this study, namely IBE 01, IBE 02, IBE 03, IBE 04, IBE 05, IBE 06, IBE 07, and IBE 08 with diverse morphological characters. The dead larvae generally showed soft, blackish/brownish, smelly, and watery characteristics. Characteristics due to infection with entomopathogen IBE 04 bacteria show the body of larvae that are soft, reddish, and smelly. The treatment of IBE 07 isolates results in the body of the dead larvae being easily ruptured, reddish, and smelly. The percentage of IBE on the mortality of H. armigera larvae is > 50%. The isolates with the highest percentage of killing the larvae were IBE 04 and IBE 07, at 94% and 88%, respectively. Keywords: biocontrol, larvicide, entomopathogenic bacteria, Helicoverpa armigera

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Anggelina, Amelia Cahya, Delianis Pringgenies et Wilis Ari Setyati. « Presence of Biosynthetic Gene Clusters (NRPS/PKS) in Actinomycetes of Mangrove Sediment in Semarang and Karimunjawa, Indonesia ». Environment and Natural Resources Journal 19, n^o 5 (26 juillet 2021) : 1–11. http://dx.doi.org/10.32526/ennrj/19/202100050.

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Actinomycetes are a group of bacteria that are widely distributed in soil, litter, water, and other natural sources. These Gram positive bacteria can produce hundreds of bioactive compounds, especially antibiotics. This research isolated culturable actinomycetes from mangrove sediments in the Semarang and Karimunjawa Island areas. The isolates that produce potential antibacterial compounds were identified by qualitative screening using the Biosynthetic Gene Cluster (NRPS/PKS) prediction approach. This research was conducted from June to November 2020. A total of 19 actinomycetes from Semarang and 17 actinomycetes from Karimunjawa were found to have at least one type of Biosynthetic Gene Cluster (NRPS, Type I or Type II PKS), but only three isolates had antibacterial activity against S. aureus, E. coli, and L. monocytogenes. Molecular identification found that the bacteria were similar to Brachybacterium paraconglomeratum (99.92%), Streptomyces pluripotens (100%), and Micromonospora chersina (99.08%). Results of the study concluded that the three bacterial isolates that had bacterial activity have similar genes with known antibiotic-producing genes and can potentially provide new antibiotic candidates.

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Zaki, Dr Neihaya Heikmat. « Effect of Bacterial Isolates From Soil Samples on Bisphenol A ». Al-Mustansiriyah Journal of Science 31, n^o 1 (1 mars 2020) : 15. http://dx.doi.org/10.23851/mjs.v31i1.686.

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Twenty five samples were collected from the soil around the Tigris River from different locations in Iraqi cities, and 45 bacterial isolates were obtained. Three of these isolates were further tested for their degrading capacity of Bisphenol A (BPA) in Basal Mineral Medium, included: Pseudomonas orizohibtanis, Escherishia coli and Proteus penneri. The optimal temperature for the removal of BPA was determined at 20˚C, 37˚ and 45˚C for 1, 5, and 15 days, and the degradation increased up to a temperature of 37°C. Growth test was performed on isolated bacteria with BisPhenol A as the sole carbon source, and with increasing incubation time, the culture grew almost linearly to 24 hours. BPA decreased after 1days after incubating with tested bacterial isolates, and almost broken after 5 days, while it disappeared after 15 days at 37C, and Pseudomonas orizohibtanis exhibited the best degradation of BPA. The absorbance peaks in the UV region appeared at 222 and 276 nm and attributed to the benzene ring and triazine ring respectively. The end products of BPA degradation were analyzed by GCMS after 15 days of incubation. The chromatogram for Pseudomanas orizohibtanis showed three peaks at retention times of 70, 210 and 280 min, and referred to hexasiloxane, heptasiloxane, and Octasiloxane respectively. The present study was aimed to isolate bacteria from the soil of the Tigris River, and determined the ability to degrade Bisphenol-A, and characterized the environmental conditions of bacterial growth, and then analysis the products of the degradation by GC-MS.

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Ventura, Marco, Roberto Reniero et Ralf Zink. « Specific Identification and Targeted Characterization ofBifidobacterium lactis from Different Environmental Isolates by a Combined Multiplex-PCR Approach ». Applied and Environmental Microbiology 67, n^o 6 (1 juin 2001) : 2760–65. http://dx.doi.org/10.1128/aem.67.6.2760-2765.2001.

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ABSTRACT The species Bifidobacterium lactis, with its main representative strain Bb12 (DSM 10140), is a yoghurt isolate used as a probiotic strain and is commercially applied in different types of yoghurts and infant formulas. In order to ensure the genetic identity and safety of this bacterial isolate, species- and strain-specific molecular tools for genetic fingerprinting must be available to identify isolated bifidobacteria or lactic acid bacteria from, e.g., various clinical environments of relevance in medical microbiology. Two opposing rRNA gene-targeted primers have been developed for specific detection of this microorganism by PCR. The specificity of this approach was evaluated and verified with DNA samples isolated from single and mixed cultures of bifidobacteria and lactobacilli (48 isolates, including the type strains of 29Bifidobacterium and 9 Lactobacillusspecies). Furthermore, we performed a Multiplex-PCR using oligonucleotide primers targeting a specific region of the 16S rRNA gene for the genus Bifidobacterium and a conserved eubacterial 16S rDNA sequence. The specificity and sensitivity of this detection with a pure culture of B. lactis were, respectively, 100 bacteria/ml after 25 cycles of PCR and 1 to 10 bacteria/ml after a 50-cycle nested-PCR approach.

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Hadi, Sapto Nugroho, Ida Widiyawati et Syaeful Anwar. « Potential Characterization and Identification of Indigenous Rhizobacteria Species of Ultisol Soil to Support the Growth of Several Superior Upland Rice Varieties ». Jurnal Penelitian Pertanian Terapan 21, n^o 3 (31 décembre 2021) : 278–89. http://dx.doi.org/10.25181/jppt.v21i3.2146.

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TG4 and SR2 were isolates of indigenous bacteria from cassava roots from Banyumas Regency, Central Java. Both are local isolates from marginal lands that can be developed as biofertilizers. This study aimed to determine the potential characteristics of bacterial isolates TG4 and SR2 in supporting the growth of superior upland rice and determining species identity based on the molecular analysis of 16S rRNA. Bacterial isolates TG4 and SR2 were determined for their potency of Plant Growth Promoting Rhizobacteria (PGPR) by fixing N2, dissolving phosphate, and producing Indole Acetic acid (IAA). Bioassays were carried out on TG4 and SR2 isolates by application of bacterial isolates (B0 = control, B1 = TG4, B2 = isolates SR2, B3 = isolates TG4 and SR2) on superior upland rice (V1 = INPAGO UNSOED 1, V2 = UNSOED PARIMAS, V3 = INPAGO 8) in sterile ultisol soil. The F test was used for bioassay data analysis, and if there was a significant difference, it was further tested with Duncan's Multiple Range Test (DMRT) with an error rate of 5%. The identity of bacterial species TG4 and SR2 was obtained by analyzing 16S rRNA sequences and genetic relationships through phylogenetic trees. The results showed that the isolates of TG4 were phosphate solubilizing bacteria and producers of IAA, while the isolates of SR2 were nitrogen fixing, phosphate solubilizing, and IAA producers. The application of bacterial isolates TG4 and SR2 significantly affected root length wet and dry weight of upland rice plants, with the highest value obtained from using a consortium of TG4 and SR2 bacteria. Bacterial isolates TG4 were identified as Bacillus albus, while SR2 as B. Paramycoides. Bacterial isolates TG4 and SR2 can be used as biofertilizers to support superior upland rice growth.

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Leite, Maria C. B. S., Andreza R. B. de Farias, Fernando J. Freire, Fernando D. Andreote, Júlia Kuklinsky-Sobral et Maria B. G. S. Freire. « Isolation, bioprospecting and diversity of salt-tolerant bacteria associated with sugarcane in soils of Pernambuco, Brazil ». Revista Brasileira de Engenharia Agrícola e Ambiental 18, suppl (2014) : 73–79. http://dx.doi.org/10.1590/1807-1929/agriambi.v18nsupps73-s79.

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ABSTRACT The selection of salinity tolerant bacteria may provide greater promotion of plant growth in soils with salt stress. This study aimed to isolate and select bacterial isolates of sugarcane, tolerant to salinity and plant growth promoters, and assess genetic diversity. To do so, endophytic root and rhizosphere of sugarcane, were isolated in culture medium with and without NaCl. The bacterial population density, the potential for biological nitrogen fixation (BNF), production of indole acetic acid (IAA), inorganic phosphate solubilization and quorum sensing molecule production were evaluated. Furthermore, the genetic diversity was assessed by Denaturing Gradient Gel Electrophoresis (DGGE) of nifH. Salinity tolerance tests were also conducted. There was no statistical difference in population density. As for the potential for BNF, IAA production, phosphate solubilization and quorum sensing molecule production, there was a high percentage of positive isolates. In the technique of DGGE nifH, the dendrogram showed high genetic variability. So there was the selection of bacteria that can contribute to the better development of sugarcane in saline soils.

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Thamer, Jasim M., Raauf M. R. Ayad et Hana B. Dalya. « The Antibacterial Activity of Callemia Sinensis (green tea) on Some Bacterial Species. » Al Mustansiriyah Journal of Pharmaceutical Sciences 10, n^o 2 (1 décembre 2011) : 46–53. http://dx.doi.org/10.32947/ajps.v10i2.295.

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The main objective of this research is to screen and to evaluate the antibacterial activity of methanol extract of Callemia Sinensis and to find out zone of inhibition against gram positive (G+ve) bacteria as well as gram negative (G-ve) bacteria.Extraction of the leaves Callemia Sinensis (green tea) and tested against 54 isolates of G+ve and G-ve bacteria which were isolated from different samples, which include pus of skin, urine and throat swabs of patients who were admitted to Al-jerahat specialized hospital in Baghdad during the period of 1/12/2008 to 1/7/2009.The methanolic extract of the plant Callemia Sinensis (green tea) showed antibacterial activity against 54 bacterial isolates that would be isolated in this study: 8 isolates of Escherichia coli, 8 isolatesof Streptococcus pneumoniae, 12 isolates of Klebsiella pneumoniae, 8 isolates of Staphylococcus aureus, 6 isolates of Proteus species, and 12 isolates of Pseudomonas aeroginosa. Callemia Sinensis have been shown to have potential chemotherapeutic activities. These data provide a direct mechanism of action for Callemia Sinensis and further support its role as a chemopreventive agents.

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McNeely, Damian, Ryan M. Chanyi, James S. Dooley, John E. Moore et Susan F. Koval. « Biocontrol of Burkholderia cepacia complex bacteria and bacterial phytopathogens by Bdellovibrio bacteriovorus ». Canadian Journal of Microbiology 63, n^o 4 (avril 2017) : 350–58. http://dx.doi.org/10.1139/cjm-2016-0612.

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Bdellovibrio and like organisms are predatory bacteria that have the unusual property of using the cytoplasmic constituents of other Gram-negative bacteria as nutrients. These predators may thus provide an alternative approach to the biocontrol of human and plant pathogens. Predators were isolated on Burkholderia cenocepacia K56-2 and J2315 as prey cells, in enrichment cultures with soil and sewage. Three isolates (DM7C, DM8A, and DM11A) were identified as Bdellovibrio bacteriovorus on the basis of morphology, a periplasmic life cycle, and 16S rRNA gene sequencing. The prey range of these isolates was tested on Burkholderia cepacia complex bacteria and several phytopathogenic bacteria of agricultural importance. Of 31 strains of the Burkholderia cepacia complex tested, only 4 were resistant to predation by strain DM7C. A subset of 9 of the prey tested were also susceptible to strains DM8A and DM11A. Of 12 phytopathogens tested, 4 were resistant to strains DM7C and DM8A, and only 2 were resistant to strain DM11A. Thus, Bdellovibrio bacteriovorus strains retrieved from environmental samples on 2 Burkholderia cenocepacia isolates from cystic fibrosis patients did not distinguish in their prey range between other isolates of that pathogen or phytopathogens. Such strains hold promise as potential wide-spectrum biocontrol agents.

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Marwah K. Khudhair et Mouruj A. AlAubydi. « DETERMINATION THE PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF BACTERIA ISOLATED FROM BURNS AND WOUNDS ». IRAQI JOURNAL OF AGRICULTURAL SCIENCES 54, n^o 1 (22 février 2023) : 93–99. http://dx.doi.org/10.36103/ijas.v54i1.1679.

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The current study conducted to identify the bacterial isolates from burns and wound infections that are responsible for various skin complication in such conditions and determination the development of antimicrobial resistance among these bacterial isolates. This study is carried out Between September 2020 to December 2020, a total number of (103) burns and wound swabs were taken from different patients from different hospitals in Baghdad city, the specimens were collected from; burns (57) and wound (46) swabs, the specimens were included; (51) female and (52) Male, the age average between (2 - 70 years). The positive bacterial containing specimens are (93) swabs, most of them are mixed (82 specimens) with different types of bacterial species and only (11 specimens) are contained with one type of bacterial isolate, while the negative bacterial containing are (10) swabs that showed no aerobic bacterial growth.. Staphylococcus sp. is recorded the most prevalence organisms found in wounds and burns 75/163(46%) included 31(41.3%) and 44(58.7%) isolated from burns and wounds respectively. Whereas Enterobacteriaceae sp. revealed that 57/163 ( 35%), 25(44%) from wounds and 32(56%) from burns. Also Pseudomonas sp. 23/163( 14.1%), Acinetobacter sp. 5/163(3.1%), and Corynebacterium sp. 3/163(1.8%) were isolated from infected wound in a percentage (47.8%,60%,and 33.3%) and from burns (52.2%, 40% and 66.7%) respectively. Another experiment was performed to measure the antimicrobial susceptibility against several antimicrobial agents included; Methicillin, Caphalothin, Tobramycin, Azithromycin, Bacitracin, Novobiocin, Levofloxacin and Sulfamethoxazole + Trimethoprim. The results showed increasing the resistance percentages among different bacterial isolates, and developed multidrug resistant bacteria.

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Kalyani, R., N. Arvind, N. Suresh Kumar, Mahendra M. Reddy et K. Dinesh. « Bacterial Colonization of Intensive Care Unit Environment and Healthcare Workers in A Tertiary Care Hospital in Kolar Region, India ». Journal of Pure and Applied Microbiology 15, n^o 1 (24 février 2021) : 402–9. http://dx.doi.org/10.22207/jpam.15.1.37.

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Direct shedding of microbes by patients and health care workers results in contamination of Intensive care unit environment. Intensive care unit acquired infections due to microbial contamination is a major concern because the patient’s immunity is already compromised. To determine the rate of bacterial contamination on environmental surfaces of Intensive care unit and health care workers and to determine the antibiogram of the isolates. Air samples and swabs from healthcare workers, their accessories, surrounding environmental surfaces were collected randomly over a period of 2 months in Adult Intensive care units. Bacterial isolates were identified by standard microbiological techniques. Antibiotic sensitivity testing was performed by Kirby Bauer disc diffusion method and data analyzed by Statistical Product and Service Solutions 22 version software. A total of 208 samples were randomly collected over 2 months, of which 56 samples yielded positive bacterial growth. Of 56 growth, 12 isolates were detected from air sampling method and 44 isolates from swabs. Among 44 isolates identified from swabs, 10 were isolated from healthcare workers, 4 from health care worker’s accessories and 30 from environmental surfaces. Six different bacterial isolates were identified, Coagulase Negative Staphylococcus (24) and Micrococcus (15) were the major isolates followed by Non fermenters (6), Staphylococcus aureus(4), Bacillus species(4) and diphtheroids (3) The antimicrobial sensitivity pattern of these bacterial isolates were sensitive to commonly used antibacterial agents. Study results showed Intensive care unit staff and environmental surfaces as probable sources of bacterial contamination. Study highlights the importance of cleaning and disinfection process and educate the health care workers about the possible sources of infections within Intensive care unit.

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Sree, Sudha. « A Study on Isolation and Identification of Exopolysaccharide (EPS) producing Bacteria from Soil ». International Journal for Research in Applied Science and Engineering Technology 9, n^o 12 (31 décembre 2021) : 650–71. http://dx.doi.org/10.22214/ijraset.2021.39341.

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Abstract: Polysaccharides are important potent molecules with their structural and compositional complexity which led to wide range of applications in various industries. The exopolysaccharides of microbial origin are released in response to extreme environmental conditions for the purpose of survival. The present study focuses on the isolation of exopolysaccharide producing bacteria from the soil sample and oil contaminated soil sample. Screening for the EPS production by the isolates is determined by the dry weight determination of precipitates of EPS and quantitative estimation of glucose content of EPS by PhenolSulphuric acid method. In the present study, out of 5 bacterial isolates isolated on screening, Lactobacillus sps and Pseudomonas sps. isolates produced the precipitates of EPS whose dry weight was determined to be 0.09g and 0.17g respectively. Further, glucose concentration of EPS was quantitatively determined. The glucose content of Lactobacillus sps. isolate was 0.1125mg/ml and Pseudomonas sps. isolate is 0.2875mg/ml. The EPS producing isolates were further grown in the presence of carbon sources like Glucose, Lactose, Maltose and Sucrose to determine the best utilizable carbon for their growth. The most utilizable carbon source for maximum growth of EPS producing isolates was determined to be sucrose with 2% concentration. All the 5 bacterial isolates were screened for their ability of antibiotic resistance. The EPS producing isolates, Lactobacillus sps, Pseudomonas sps were found to be resistant towards all the antimicrobial agents owing to the presence of EPS protective layer around their cell wall than non-EPS producing isolates. Keywords: Exopolysaccharide, Screening, Carbon sources, Antibiotic resistance.

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Roane, T. M., et S. T. Kellogg. « Characterization of bacterial communities in heavy metal contaminated soils ». Canadian Journal of Microbiology 42, n^o 6 (1 juin 1996) : 593–603. http://dx.doi.org/10.1139/m96-080.

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Heavy metal pollution is a principle source of environmental contamination. We analyzed heavy metal impacted soil microbial communities and found that, in general, although lead adversely affected biomass, metabolic activity, and diversity, autochthonous lead- and cadmium-resistant isolates were found. In several metal-stressed soils, the microbial community consisted of two populations, either resistant or sensitive to lead. Additionally, a lead-resistant isolate was isolated from a control soil with no known previous exposure to lead, suggesting widespread lead resistance. Lead-resistant genera isolated included Pseudomonas, Bacillus, Corynebacterium, and Enterobacter species. Plasmids, ranging from 5 to 260 kb, were not detected through standard purifications from lead-resistant isolates. Positive correlations existed between antibiotic resistance and isolation habitat for lead-resistant strains, microbial metabolic activity and soil type, soluble lead concentration and microbial diversity, and arsenic concentration and total or viable cell concentrations.Key words: heavy metal, lead, cadmium, soil bacteria, stress, remediation.

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