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1
HUSSEIN, HUSSEIN S., LAURIE M. BOLLINGER, and MARK R. HALL. "Growth and Enrichment Medium for Detection and Isolation of Shiga Toxin–Producing Escherichia coli in Cattle Feces." Journal of Food Protection 71, no. 5 (2008): 927–33. http://dx.doi.org/10.4315/0362-028x-71.5.927.
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Detection methods of Shiga toxin–producing Escherichia coli (STEC) in cattle feces varied in using enrichment media containing different antibiotic combinations. To examine efficacy of a new detection method for STEC, three O157:H7 (ATCC 43889, 43890, and 43895) and 41 non-O157:H7 (members of the O1, O15, O26, O86, O103, O111, O125, O127, O128, O136, O146, O153, O158, O165, O166, and O169 serogroups) isolates were tested. These isolates were grown in tryptic soy broth for 6 h, and their concentrations were determined before inoculation of tubes containing 1 g of cattle feces (sterile [experiment 1; evaluating growth] and fresh [experiment 2; evaluating enrichment]) to simulate the high and low levels of STEC shedding by cattle (105 versus 102 CFU/g feces, respectively). Eight STEC isolates (the three O157:H7 and five non-O157:H7 selected at random) were tested at a very low level (10 CFU/g feces). The feces were incubated in 50 ml of brain heart infusion broth containing potassium tellurite, novobiocin, and vancomycin (2.5, 20, and 40 mg/liter, respectively) and cefixime (50 μg/liter) at 37°C for 12 h and tested for STEC (VTEC [verotoxin-producing E. coli]–Screen assay [agglutination immunoassay]). Potential STEC isolates were recovered, characterized biochemically, serotyped, and tested for toxin production using Vero (African green monkey kidney) cell toxicity assay and agglutination immunoassay. In both experiments, all the STEC isolates used for fecal inoculation were recovered at the concentrations tested. Our medium supported growth of and enrichment for a wide range of STEC isolates.
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Son, W. G., T. A. Graham та V. P. J. Gannon. "Immunological Characterization of Escherichia coli O157:H7 Intimin γ1". Clinical and Vaccine Immunology 9, № 1 (2002): 46–53. http://dx.doi.org/10.1128/cdli.9.1.46-53.2002.
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ABSTRACT Portions of the intimin genes of Escherichia coli O157:H7 strain E319 and of the enteropathogenic E. coli O127:H6 strain E2348/69 were amplified by PCR and cloned into pET-28a(+) expression vectors. The entire 934 amino acids (aa) of E. coli O157:H7 intimin, the C-terminal 306 aa of E. coli O157:H7 intimin, and the C-terminal 311 aa of E. coli O127:H6 intimin were expressed as proteins fused with a six-histidine residue tag (six-His tag) in pET-28a(+). Rabbit antisera raised against the six-His tag-full-length E. coli O157:H7 intimin protein fusion cross-reacted in slot and Western blots with outer membrane protein preparations from the majority of enterohemorrhagic and enteropathogenic E. coli serotypes which have the intimin gene. The E. coli strains tested included isolates from humans and animals which produce intimin typesα (O serogroups 86, 127, and 142), β1 (O serogroups 5, 26, 46, 69, 111, 126, and 128), γ1 (O serogroups 55, 145, and 157), γ2 (O serogroups 111 and 103), and ε (O serogroup 103) and a nontypeable intimin (O serogroup 80), results based on intimin type-specific PCR assays. Rabbit antisera raised against the E. coli O157:H7 C-terminal fusion protein were much more intimin type-specific than those raised against the full-length intimin fusion protein, but some cross-reaction with other intimin types was also observed for these antisera. In contrast, the monoclonal antibody Intγ1.C11, raised against the C-terminal E. coli O157 intimin, reacted only with preparations from intimin γ1-producing E. coli strains such as E. coli O157:H7.
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Gamage, Shantini D., Colleen M. McGannon, and Alison A. Weiss. "Escherichia coli Serogroup O107/O117 Lipopolysaccharide Binds and Neutralizes Shiga Toxin 2." Journal of Bacteriology 186, no. 16 (2004): 5506–12. http://dx.doi.org/10.1128/jb.186.16.5506-5512.2004.
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ABSTRACT The AB5 toxin Shiga toxin 2 (Stx2) has been implicated as a major virulence factor of Escherichia coli O157:H7 and other Shiga toxin-producing E. coli strains in the progression of intestinal disease to more severe systemic complications. Here, we demonstrate that supernatant from a normal E. coli isolate, FI-29, neutralizes the effect of Stx2, but not the related Stx1, on Vero cells. Biochemical characterization of the neutralizing activity identified the lipopolysaccharide (LPS) of FI-29, a serogroup O107/O117 strain, as the toxin-neutralizing component. LPSs from FI-29 as well as from type strains E. coli O107 and E. coli O117 were able bind Stx2 but not Stx1, indicating that the mechanism of toxin neutralization may involve inhibition of the interaction between Stx2 and the Gb3 receptor on Vero cells.
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NARANG, NEELAM, PINA M. FRATAMICO, GLENN TILLMAN, KITTY PUPEDIS, and WILLIAM C. CRAY. "Performance Comparison of a fliCh7 Real-Time PCR Assay with an H7 Latex Agglutination Test for Confirmation of the H Type of Escherichia coli O157:H7†." Journal of Food Protection 72, no. 10 (2009): 2195–97. http://dx.doi.org/10.4315/0362-028x-72.10.2195.
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Escherichia coli O157:H7 is a foodborne pathogen that causes hemorrhagic colitis and hemolytic uremic syndrome. Positive identification of E. coli O157:H7 is made using biochemical tests and specific antisera or latex agglutination reagents for the O157 and H7 antigens. However, under certain conditions, some E. coli O157:H7 isolates can appear to be nonreactive with H7 antisera and may require multiple passages on motility medium to restore H7 antigenicity. In this study, we compared the performance of a real-time PCR test with that of a method using latex agglutination reagents to detect the presence of the fliCh7 gene or the H7 antigen, respectively, in E. coli O157:H7 isolates. One hundred twenty-six E. coli strains were tested including reference strains and strains isolated from meat. Lyophilized E. coli O157:H7 isolates were rehydrated and were plated on sheep blood agar without passage on motility medium. All strains were analyzed in parallel by a real-time PCR test targeting the fliCh7 gene and by a latex agglutination test that detects the H7 antigen. The real-time PCR assay showed 100% agreement with the H7 status reported for reference strains and E. coli O157:H7 meat isolates. The latex agglutination test results agreed with the H7 status reported for the E. coli O157:H7 reference strains and non-O157:H7 strains, except for one, E. coli O117:H7; however, 42% (42 of 100) of the E. coli O157:H7 meat isolates tested negative for the H7 antigen by latex agglutination. The real-time fliCh7 PCR test can be used to confirm E. coli O157:H7 strains that are not expressing the immunoreactive H7 antigen.
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KANG, DONG-HYUN, and DANIEL Y. C. FUNG. "Development of a Medium for Differentiation between Escherichia coli and Escherichia coli O157:H7." Journal of Food Protection 62, no. 4 (1999): 313–17. http://dx.doi.org/10.4315/0362-028x-62.4.313.
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A new medium (Escherichia coli O157:H7 medium: EOH) was developed for differentiation between E. coli and E. coli O157:H7. The EOH medium was compared with sorbitol MacConkey agar (SMAC), which is the most popular medium to enumerate E. coli O157:H7. Several combinations of 35 dyes were evaluated to develop the new medium. Indigo carmine (0.03 g/liter) and phenol red (0.036 g/liter) were found as the best combination for differentiation between E. coli O157:H7 and E. coli and added to the basal agar medium (SMAC medium excluding neutral red and crystal violet) for EOH medium. On the dark blue EOH medium, E. coli produced a yellow color with clear zone, whereas E. coli O157:H7 produced a red color without clear zone. For differentiation between E. coli and E. coli O157:H7, EOH has much better potential than SMAC. Furthermore, the red color produced by normal E. coli in SMAC may mask the light gray color produced by E. coli O157: H7, whereas the yellow color with clear zone did not mask the red color without clear zone in the EOH medium. The recovery numbers of E. coli O157:H7 from inoculated ground beef, pork, and turkey were not significantly different between SMAC and EOH media (P > 0.05). The recovery rates of heat- and cold-injured E. coli O157:H7 also were not significantly different (P > 0.05).
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LEENANON, B., and M. A. DRAKE. "Acid Stress, Starvation, and Cold Stress Affect Poststress Behavior of Escherichia coli O157:H7 and Nonpathogenic Escherichia coli†." Journal of Food Protection 64, no. 7 (2001): 970–74. http://dx.doi.org/10.4315/0362-028x-64.7.970.
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The effects of acid shock, acid adaptation, starvation, and cold stress of Escherichia coli O157:H7 (ATCC 43895), an rpo S mutant (FRIK 816-3), and nonpathogenic E. coli (ATCC 25922) on poststress heat resistance and freeze–thaw resistance were investigated. Following stress, heat tolerance at 56°C and freeze–thaw resistance at −20 to 21°C were determined. Heat and freeze–thaw resistance of E. coli O157:H7 and nonpathogenic E. coli was enhanced after acid adaptation and starvation. Following cold stress, heat resistance of E. coli O157:H7 and nonpathogenic E. coli was decreased, while freeze–thaw resistance was increased. Heat and freeze–thaw resistance of the rpoS mutant was enhanced only after acid adaptation. Increased or decreased tolerance of acid-adapted, starved, or cold-stressed E. coli O157:H7 cells to heat or freeze–thaw processes should be considered when processing minimally processed or extended shelf-life foods.
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MEKATA, HIROHISA, ATSUSHI IGUCHI, KIMIKO KAWANO, YUMI KIRINO, IKUO KOBAYASHI, and NAOAKI MISAWA. "Identification of O Serotypes, Genotypes, and Virulotypes of Shiga Toxin–Producing Escherichia coli Isolates, Including Non-O157 from Beef Cattle in Japan." Journal of Food Protection 77, no. 8 (2014): 1269–74. http://dx.doi.org/10.4315/0362-028x.jfp-13-506.
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Bovines are recognized as an important reservoir of Shiga toxin–producing Escherichia coli (STEC). Although STEC strains are significant foodborne pathogens, not all of the STEC held by cattle are pathogenic, and which type of STEC that will become epidemic in humans is unpredictable. Information about the prevalence of serotype and virulence gene distribution in beef cattle is insufficient to develop monitoring and controlling activities for a food safety and security program. Thus, this study investigated the prevalence of O157 and non-O157 STEC in Japanese beef cattle and characterized the isolates by the type of O antigen and several virulence markers to help predict the pathogenicity. In this study, 64.2%(176 of 274) of enrichment cultures of fecal samples collected from an abattoir and farms were stx1 and/or stx2 positive by PCR. STEC strains were isolated from 22.1% (39 of 176) of the positive fecal samples, and these isolates represented 17 types of O antigen (O1, O2 or O50, O5, O8, O55, O84, O91, O109, O113, O136, O150, O156, O157, O163, O168, O174, and O177). Two selective media targeting major STEC groups, cefixime-tellurite sorbitol MacConkey agar and CHROMagar O26/O157, allowed isolation of a variety of STEC strains. The most frequently isolated STEC was O113 (8 of 39), which has previously been reported as a cause of foodborne infections. Although most of the O113 STEC isolated from infected patients possessed the enterohemolysin (hlyA) gene, none of the O113 STEC cattle isolates possessed the hlyA gene. The second most common isolate was O157 (6 of 39), and all these isolates contained common virulence factors, including eae, tir, lpf1, lpf2, and hlyA. This study shows the prevalence of O157 and non-O157 STEC in Japanese beef cattle and the relationship of O antigen and virulotypes of the isolates. This information may improve identification of the source of infection, developing surveillance programs or the current understanding of virulence factors of STEC infections.
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BOSILEVAC, JOSEPH M., RONG WANG, BRANDON E. LUEDTKE, SUSANNE HINKLEY, TOMMY L. WHEELER, and MOHAMMAD KOOHMARAIE. "Characterization of Enterohemorrhagic Escherichia coli on Veal Hides and Carcasses." Journal of Food Protection 80, no. 1 (2016): 136–45. http://dx.doi.org/10.4315/0362-028x.jfp-16-247.
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ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin–producing E. coli associated with the most severe forms of foodborne illnesses. The U.S. Department of Agriculture, Food Safety and Inspection Service has identified a higher percentage of non-O157 EHEC compared with E. coli O157:H7–positive samples collected from veal trimmings than from products produced from other cattle slaughter classes. Therefore samples were collected from hides and preevisceration carcasses at five veal processors to assess E. coli O157:H7 and non-O157 EHEC contamination during bob veal and formula-fed veal dressing procedures. E. coli O157:H7 prevalence was measured by culture isolation and found to be on 20.3% of hides and 6.7% of carcasses. In contrast, a non-O157 EHEC molecular screening assay identified 90.3% of hides and 68.2% of carcasses as positive. Only carcass samples were taken forward to culture confirmation and 38.7% yielded one or more non-O157 EHEC isolates. The recovery of an EHEC varied by plant and sample collection date; values ranged from 2.1 to 87.8% among plants and from 4.2 to 64.2% within the same plant. Three plants were resampled after changes were made to sanitary dressing procedures. Between the two collection times at the three plants, hide-to-carcass transfer of E. coli O157:H7 and non-O157 EHEC was significantly reduced. All adulterant EHEC serogroups (O26, O45, O103, O111, O121, and O145) were isolated from veal carcasses as well as four other potentially pathogenic serogroups (O5, O84, O118, and O177). Bob veal was found to have a greater culture prevalence of E. coli O157:H7 and greater positive molecular screens for non-O157 EHEC than formula-fed veal (P < 0.05), but the percentage of culture-confirmed non-O157 EHEC was not different (P > 0.05) between the two types of calves. EHEC-O26, -O111, and -O121 were found more often in bob veal (P < 0.05), whereas EHEC-O103 was found more often in formula-fed veal (P < 0.05).
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Elliott, Simon J., Jie Yu, and James B. Kaper. "The Cloned Locus of Enterocyte Effacement from EnterohemorrhagicEscherichia coli O157:H7 Is Unable To Confer the Attaching and Effacing Phenotype upon E. coliK-12." Infection and Immunity 67, no. 8 (1999): 4260–63. http://dx.doi.org/10.1128/iai.67.8.4260-4263.1999.
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ABSTRACT The locus of enterocyte effacement (LEE) pathogenicity island of enterohemorrhagic Escherichia coli (EHEC) O157:H7 possesses the same genes in identical order and orientation as the LEE of enteropathogenic E. coli (EPEC) O127:H6 but is unable to form attaching and effacing (A/E) lesions or to secrete Esp proteins when it is cloned in an E. coli K-12 background. The A/E phenotype could not be restored by trans complementation with a variety of cloned EPEC LEE fragments, suggesting functional and/or regulatory differences between the LEE pathogenicity islands of EPEC O127:H6 and EHEC O157:H7.
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ENACHE, ELENA, EMILY C. MATHUSA, PHILIP H. ELLIOTT, et al. "Thermal Resistance Parameters for Shiga Toxin–Producing Escherichia coli in Apple Juice." Journal of Food Protection 74, no. 8 (2011): 1231–37. http://dx.doi.org/10.4315/0362-028x.jfp-10-488.
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The purpose of the present study was to determine the heat resistance of six non-O157 Shiga toxin–producing Escherichia coli (STEC) serotypes in comparison to E. coli O157:H7 in single-strength apple juice without pulp. The thermal parameters for stationary-phase and acid-adapted cells of E. coli strains from serogroups O26, O45, O103, O111, O121, O145, and O157:H7 were determined by using an immersed coil apparatus. The most heat-sensitive serotype in the present study was O26. Stationary-phase cells for serotypes O145, O121, and O45 had the highest D56°C-value among the six non-O157 serotypes studied, although all were significantly lower (P < 0.05) than that of E. coli O157:H7. At 60°C E. coli O157:H7 and O103 demonstrated the highest D-values (1.37 ± 0.23 and 1.07 ± 0.03 min, respectively). The D62°C for the most heat-resistant strain belonging to the serotype O145 was similar (P > 0.05) to that for the most resistant O157:H7 strain (0.61 ± 0.17 and 0.60 ± 0.09 min, respectively). The heat resistance for stationary-phase cells was generally equal to or higher than that of acid-adapted counterparts. Although E. coli O157:H7 revealed D-values similar to or higher than the individual six non-O157 STEC serotypes in apple juice, the z-values for most non-O157 STEC tested strains were greater than those of E. coli O157:H7. When data were used to calculate heat resistance parameters at a temperature recommended in U.S. Food and Drug Administration guidance to industry, the D71.1°C for E. coli O157:H7 and non-O157 STEC serotypes were not significantly different (P > 0.05).
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FRATAMICO, PINA M., and LORI K. BAGI. "Comparison of Methods for Detection and Isolation of Cold- and Freeze-Stressed Escherichia coli O157:H7 in Raw Ground Beef†." Journal of Food Protection 70, no. 7 (2007): 1663–69. http://dx.doi.org/10.4315/0362-028x-70.7.1663.
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A comparison was made of the relative efficiencies of three enrichment media, RapidChek Escherichia coli O157:H7 enrichment broth (REB), R&F broth (RFB), and modified E. coli broth containing novobiocin (mEC+n), and four selective plating media for detection of cold- and freeze-stressed E. coli O157:H7 in raw ground beef. Ground beef (25 g) was inoculated with E. coli O157:H7 at ≤0.5 and ≤2 CFU/g, and samples were then enriched immediately or were stored at 4°C for 72 h or at −20°C for 2 weeks and then enriched. After 8 or 20 h of enrichment, the cultures were plated onto R&F E. coli O157: H7 chromogenic plating medium, cefixime-tellurite sorbitol MacConkey agar, CHROMagar O157, and Rainbow agar O157 and tested using the RapidChek E. coli O157 lateral flow immunoassay and a multiplex PCR assay targeting the E. coli O157: H7 eae, stx1, and stx2 genes. Recovery of E. coli O157:H7 on the four agar media was 4.0 to 7.9 log CFU/ml with the REB enrichment, 1.4 to 7.4 log CFU/ml with RFB, 1.7 to 6.7 log CFU/ml with mEC+n incubated at 42°C, and 1.3 to 3.3 log CFU/ml from mEC+n incubated at 35°C. The percentages of positive ground beef samples containing nonstressed, cold-stressed, and freeze-stressed E. coli O157:H7 as obtained by plating, the immunoassay, and the PCR assay were 97, 88, and 97%, respectively, with REB, 92, 81, and 78%, respectively, with RFB, 97, 58, and 53%, respectively, with mEC+n incubated at 42°C, and 22, 31, and 25%, respectively, with mEC+n incubated at 35°C. Logistic regression analyses of the data indicated significant main effects of treatment, type of medium, enrichment time, inoculum concentration, and detection method. In particular, a positive result was 1.1 times more likely to occur after 20 h of enrichment than after 8 h, 25 times more likely with RFB and REB than with mEC+nat35°C, 3.7 times more likely with an initial inoculum of ≤2.0 CFU/g than with ≤0.5 CFU/g, 2.5 to 3 times more likely using freeze-stressed or nonstressed bacteria than with cold-stressed bacteria, and 2.5 times more likely by plating than by the immunoassay or the PCR assay. REB had better overall performance for enrichment of cold- and freeze-stressed E. coli O157:H7 present in ground beef than did the other media examined.
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Baines, Danica, Stephanie Erb, and Tim McAllister. "Stx2 from enterohemorrhagic Escherichia coli O157:H7 promotes colonization in the intestine of cattle." Canadian Journal of Animal Science 88, no. 4 (2008): 581–84. http://dx.doi.org/10.4141/cjas08016.
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Cattle act as the main reservoir for enterohemorrhagic Escherichia coli O157:H7, a bacterium that causes serious human disease outbreaks. It is currently not clear which bacterial or animal factors contribute to E. coli O157:H7 colonization in cattle. We recently identified mucosal hemorrhages in the jejunum, ileum and colon of persistent shedding cattle that were associated with E. coli O157:H7 colonization. This suggested that E. coli O157:H7-secreted cytotoxins may be involved in the E. coli O157:H7 colonization process. Further studies confirmed that E. coli O157:H7-secreted cytotoxins were toxic to cattle enterocytes and enhanced E. coli O157:H7 colonization of intestinal tissues. The current study examined the contribution of Stx2 to the earlier reported E. coli O157:H7- associated mucosal damage and secreted cytotoxin activity. Stx2 was not cytotoxic to enterocytes, but did enhance E. coli O157:H7 adherence to intestinal tissues in cattle. This is the first report of an E. coli O157:H7 virulence factor that can directly influence the E. coli O157:H7 colonization process in cattle. Key words: Stx2, Escherichia coli O157:H7, cattle, intestine, colonization
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Sancak, Yakup Can, Hakan Sancak, and Ozgur Isleyici. "Presence of Escherichia coli O157 and O157:H7 in raw milk and Van herby cheese." Bulletin of the Veterinary Institute in Pulawy 59, no. 4 (2015): 511–14. http://dx.doi.org/10.1515/bvip-2015-0076.
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Abstract The Shiga toxin-producing Escherichia coli (STEC) strains are currently considered important emerging pathogens threatening public health. Among Shiga toxin-producing Escherichia coli, E. coli O157:H7 strains have emerged as important human pathogens. This study was conducted to determine the presence of Escherichia coli O157 and O157:H7 in raw milk samples and Van herby cheese samples. For this purpose, 100 samples of raw milk were collected and 100 samples of herby cheese sold for consumption in Van province in Turkey were obtained from grocers and markets in order to detect the presence of Escherichia coli O157 and O157:H7. The method of E. coli O157 and O157:H7 isolation proposed by the Food and Drug Administration (FDA) was used. E. coli O157 in raw milk and herby cheese samples was found in 11% and 6% of samples respectively, and E. coli O157:H7 was found in 2% of herby cheese samples. No E. coli O157:H7 was detected in raw milk samples. This study showed that raw milk was contaminated with E. coli O157 and herby cheese was contaminated with both E. coli O157 and E. coli O157:H7; therefore, herby cheese poses a serious risk to public health.
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Mackenzie, A. M. R., P. Lebel, E. Orrbine, et al. "Sensitivities and Specificities of Premier E. coliO157 and Premier EHEC Enzyme Immunoassays for Diagnosis of Infection with Verotoxin (Shiga-Like Toxin)-Producing Escherichia coli." Journal of Clinical Microbiology 36, no. 6 (1998): 1608–11. http://dx.doi.org/10.1128/jcm.36.6.1608-1611.1998.
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This study describes the performance of two rapid enzyme immunoassays, Premier E. coli O157 and Premier EHEC (Meridian Diagnostics Inc., Cincinnati, Ohio) for the detection in stools of Escherichia coli O157 and verotoxins (Shiga-like toxins), respectively. Both tests were performed on stools from 876 children presenting to eight emergency departments with diarrhea. Standard culture, including E. coli O157:H7 isolation, was performed, and paired sera were taken for anti-O157-lipopolysaccharide antibody determination. Stools from patients enrolled in the study, and those yielding discordant results, were sent to a reference laboratory for repeat testing and further investigation, including cytotoxicity and non-O157 verotoxin-producingE. coli culture. Results were classified as field results (obtained in the eight site laboratories) and resolved results (obtained after repeat testing in the central laboratory). The “gold standard” for sensitivity of both tests and for specificity of Premier E. coli O157 was isolation of E. coli O157:H7 or a fourfold anti-O157 antibody rise. Specimens positive by the Premier EHEC test and negative for E. coli O157 culture were examined for non-O157 verotoxin-producingE. coli. The field sensitivity of PremierE. coli O157 was 86%, that of Premier EHEC was 89%, and the specificity of Premier E. coli O157 was 98%. Ten of 13 discordant Premier E. coli O157 results were reassigned as true results after repeat testing. Ten non-O157 verotoxin-producing E. coli isolates were recovered from Premier EHEC-positive, E. coli O157 culture-negative stools. Only one specimen gave an unequivocally false-positive Premier EHEC result. Both tests are highly sensitive and are specific if correctly performed. The Premier EHEC test will be particularly valuable as a practical routine test for the detection of non-O157 verotoxin-producing E. coli.
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JORDAN, KIERAN N., and MATTHEW M. MAHER. "Sensitive Detection of Escherichia coli O157:H7 by Conventional Plating Techniques." Journal of Food Protection 69, no. 3 (2006): 689–92. http://dx.doi.org/10.4315/0362-028x-69.3.689.
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The direct detection and estimation of concentration of Escherichia coli O157:H7 down to 1 CFU/g of cheese was achieved by conventional plating techniques. Cheese was manufactured with unpasteurized milk inoculated with E. coli O157: H7 at 34 ± 3 CFU/ml. The numbers of E. coli O157:H7 were monitored during cheese ripening by plating on sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC) and on CT-O157:H7 ID medium. Using the pour plate method, E. coli O157:H7 colonies could easily be distinguished from non-O157:H7 colonies on CT-O157:H7 ID medium but not on CT-SMAC. Higher numbers of E. coli O157:H7 were detectable with O157:H7 ID medium. Latex agglutination and PCR were used to confirm the identification of typical E. coli O157:H7 colonies, and nontypical colonies as not being E. coli O157:H7. As few as 1 CFU/g of cheese could be detected. E. coli O157:H7 also was detected in deliberately contaminated milk at concentrations as low as 4 CFU/10 ml.
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Wirathi, Ni Wayan Purni, Retno Kawuri, and Ida Bagus Darmayasa. "Eliminasi Escherichia coli O157:H7 Yang Diisolasi Dari Daging Sapi Di Rumah Potong Hewan (RPH) Dan Pasar Tradisional." Metamorfosa: Journal of Biological Sciences 7, no. 2 (2020): 56. http://dx.doi.org/10.24843/metamorfosa.2020.v07.i02.p08.
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Penelitian ini dilakukan untuk mengetahui kualitas daging sapi di RPH dan pasar Tradisional di Denpasar, Badung, dan Klungkung ditinjau dari angka Escherichia coli dan E. coli O157:H7 yang dicurigai mencemari daging sapi. Penelitian eksperimen dilakukan di laboratorium dengan uji pemanasan terhadap E. coli O157:H7 untuk mengetahui ketahanan panas dari E. coli O157:H7. Daging sapi yang diambil di pasar Nyanggelan Panjer menunjukkan nilai angka E. coli paling tinggi yaitu 222,3 koloni/g, dan nilai E. coli paling rendah didapat pada daging sapi yang diambil di RPH Kaliunda yaitu 2,3 koloni/g. Hasil identifikasi pada 39 sampel daging sapi menunjukkan semua sampel daging sapi mengandung E. coli, sebanyak 24 sampel positif E. coli O157, dan 9 sampel lainnya menunjukkan positif E. coli O157:H7. Perlakuan pemanasan pada suhu 60? masih ada pertumbuhan koloni E. coli O157:H7 pada cawan Petri, namun telah terjadi penurunan dari jumlah koloni awal sebelum proses pemanasan. Seluruh lokasi pengambilan 100% terkontaminasi E. coli, 61.5% positif E. coli O157, dan 25.6% positif E. coli O157:H7. Pemanasan 65? selama 15 detik dan 70? selama 5 detik dapat membunuh E. coli O157:H7 pada daging sapi.
 
 Kata kunci: E. coli O157:H7, daging sapi, RPH, pasar tradisional, proses pemanasan
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Lahti, Elina, Olli Ruoho, Leila Rantala, Marja-Liisa Hänninen, and Tuula Honkanen-Buzalski. "Longitudinal Study of Escherichia coli O157 in a Cattle Finishing Unit." Applied and Environmental Microbiology 69, no. 1 (2003): 554–61. http://dx.doi.org/10.1128/aem.69.1.554-561.2003.
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ABSTRACT In a longitudinal study in a Finnish cattle finishing unit we investigated excretion and sources of Escherichia coli O157 in bulls from postweaning until slaughter. Three groups of 31 to 42 calves were sampled in a calf transporter before they entered the farm and four to seven times at approximately monthly intervals at the farm. All calves sampled in the livestock transporter were negative for E. coli O157 on arrival, whereas positive animals were detected 1 day later. During the fattening period the E. coli O157 infection rate varied between 0 and 38.5%. The animals were also found to be shedding during the cold months. E. coli O157 was isolated from samples taken from water cups, floors, and feed passages. E. coli O157 was detected in 9.7 to 38.9% of the fecal samples taken at slaughter, while only two rumen samples and one carcass surface sample were found to be positive. E. coli O157 was isolated from barn surface samples more often when the enrichment time was 6 h than when the enrichment time was 24 h (P < 0.0001). Fecal samples taken at the abattoir had lower counts (≤0.4 MPN/g) than fecal samples at the farm (P < 0.05). E. coli O157 was isolated more often from 10-g fecal samples than from 1-g fecal samples (P < 0.0001). Most farm isolates belonged to one pulsed-field gel electrophoresis (PFGE) genotype (79.6%), and the rest belonged to closely related PFGE genotypes. In conclusion, this study indicated that the finishing unit rather than introduction of new cattle was the source of E. coli O157 at the farm and that E. coli O157 seemed to persist well on barn surfaces.
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Hoffman, Mark A., Christian Menge, Thomas A. Casey, William Laegreid, Brad T. Bosworth, and Evelyn A. Dean-Nystrom. "Bovine Immune Response to Shiga-Toxigenic Escherichia coli O157:H7." Clinical and Vaccine Immunology 13, no. 12 (2006): 1322–27. http://dx.doi.org/10.1128/cvi.00205-06.
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ABSTRACT Although cattle develop humoral immune responses to Shiga-toxigenic (Stx+) Escherichia coli O157:H7, infections often result in long-term shedding of these human pathogenic bacteria. The objective of this study was to compare humoral and cellular immune responses to Stx+ and Stx− E. coli O157:H7. Three groups of calves were inoculated intrarumenally, twice in a 3-week interval, with different strains of E. coli: a Stx2-producing E. coli O157:H7 strain (Stx2+O157), a Shiga toxin-negative E. coli O157:H7 strain (Stx−O157), or a nonpathogenic E. coli strain (control). Fecal shedding of Stx2+O157 was significantly higher than that of Stx−O157 or the control. Three weeks after the second inoculation, all calves were challenged with Stx2+O157. Following the challenge, levels of fecal shedding of Stx2+O157 were similar in all three groups. Both groups inoculated with an O157 strain developed antibodies to O157 LPS. Calves initially inoculated with Stx−O157, but not those inoculated with Stx2+O157, developed statistically significant lymphoproliferative responses to heat-killed Stx2+O157. These results provide evidence that infections with STEC can suppress the development of specific cellular immune responses in cattle, a finding that will need to be addressed in designing vaccines against E. coli O157:H7 infections in cattle.
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Wang, Xiaoqing, Sun-Young Lee, Shahina Akter, and Md Amdadul Huq. "Probiotic-Mediated Biosynthesis of Silver Nanoparticles and Their Antibacterial Applications against Pathogenic Strains of Escherichia coli O157:H7." Polymers 14, no. 9 (2022): 1834. http://dx.doi.org/10.3390/polym14091834.
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The present study aimed to suggest a simple and environmentally friendly biosynthesis method of silver nanoparticles (AgNPs) using the strain Bacillus sonorensis MAHUQ-74 isolated from kimchi. Antibacterial activity and mechanisms of AgNPs against antibiotic-resistant pathogenic strains of Escherichia coli O157:H7 were investigated. The strain MAHUQ-74 had 99.93% relatedness to the B. sonorensis NBRC 101234T strain. The biosynthesized AgNPs had a strong surface plasmon resonance (SPR) peak at 430 nm. The transmission electron microscope (TEM) image shows the spherical shape and size of the synthesized AgNPs is 13 to 50 nm. XRD analysis and SAED pattern revealed the crystal structure of biosynthesized AgNPs. Fourier transform infrared spectroscopy (FTIR) data showed various functional groups associated with the reduction of silver ions to AgNPs. The resultant AgNPs showed strong antibacterial activity against nine E. coli O157:H7 pathogens. Minimum inhibitory concentration (MIC) values of the AgNPs synthesized by strain MAHUQ-74 were 3.12 μg/mL for eight E. coli O157:H7 strains and 12.5 μg/mL for strain E. coli ATCC 25922. Minimum bactericidal concentrations (MBCs) were 25 μg/mL for E. coli O157:H7 ATCC 35150, E. coli O157:H7 ATCC 43895, E. coli O157:H7 ATCC 43890, E. coli O157:H7 ATCC 43889, and E. coli ATCC 25922; and 50 μg/mL for E. coli O157:H7 2257, E. coli O157: NM 3204-92, E. coli O157:H7 8624 and E. coli O157:H7 ATCC 43894. FE-SEM analysis demonstrated that the probiotic-mediated synthesized AgNPs produced structural and morphological changes and destroyed the membrane integrity of pathogenic E. coli O157:H7. Therefore, AgNPs synthesized by strain MAHUQ-74 may be potential antibacterial agents for the control of antibiotic-resistant pathogenic strains of E. coli O157:H7.
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Blanco, Jorge, Miguel Blanco, Jesus E. Blanco, et al. "Verotoxin-Producing Escherichia coli in Spain: Prevalence, Serotypes, and Virulence Genes of O157:H7 and Non-O157 VTEC in Ruminants, Raw Beef Products, and Humans." Experimental Biology and Medicine 228, no. 4 (2003): 345–51. http://dx.doi.org/10.1177/153537020322800403.
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In Spain, as in many other countries, verotoxin-producing Escherichia coli (VTEC) strains have been frequently isolated from cattle, sheep, and foods. VTEC strains have caused seven outbreaks in Spain (six caused by E. coli O157:H7 and one by E. coli O111:H– [nonmotile]) in recent years. An analysis of the serotypes indicated serological diversity. Among the strains isolated from humans, serotypes O26:H11, O111:H–, and O157:H7 were found to be more prevalent. The most frequently detected serotypes in cattle were O20:H19, O22:H8, O26:H11, O77:H41, O105:H18, O113:H21, O157:H7, O171:H2, and OUT (O untypeable):H19. Different VTEC serotypes (e.g., O5:H–, O6:H10, O91:H–, O117:H–, O128:H–, O128:H2, O146:H8, O146:H21, O156:H–, and OUT:H21) were found more frequently in sheep. These observations suggest a host serotype specificity for some VTEC. Numerous bovine and ovine VTEC serotypes detected in Spain were associated with human illnesses, confirming that ruminants are important reservoirs of pathogenic VTEC. VTEC can produce one or two toxins (VT1 and VT2) that cause human illnesses. These toxins are different proteins encoded by different genes. Another virulence factor expressed by VTEC is the protein intimin that is responsible for intimate attachment of VTEC and effacing lesions in the intestinal mucosa. This virulence factor is encoded by the chromosomal gene eae. The eae gene was found at a much less frequency in bovine (17%) and ovine (5%) than in human (45%) non-O157 VTEC strains. This may support the evidence that the eae gene contributes significantly to the virulence of human VTEC strains and that many animal non-O157 VTEC strains are less pathogenic to humans.
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MIYAMOTO, TAKAHISA, NATSUKO ICHIOKA, CHIE SASAKI, et al. "Polymerase Chain Reaction Assay for Detection of Escherichia coli O157:H7 and Escherichia coli O157:H−." Journal of Food Protection 65, no. 1 (2002): 5–11. http://dx.doi.org/10.4315/0362-028x-65.1.5.
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The DNA band patterns generated by polymerase chain reaction (PCR) using the du2 primer and template DNAs from various strains of Escherichia coli and non–E. coli bacteria were compared. Among three to five prominent bands produced, the three bands at about 1.8, 2.7, and 5.0 kb were detected in all of the E. coli O157 strains tested. Some nonpathogenic E. coli and all pathogenic E. coli except E. coli O157 showed bands at 1.8 and 5.0 kb. It seems that the band at 2.7 kb is specific to E. coli O157. Sequence analysis of the 2.7-kb PCR product revealed the presence of a DNA sequence specific to E. coli O157:H− and E. coli O157:H7. Since the DNA sequence from base 15 to base 1008 of the PCR product seems to be specific to E. coli O157, a PCR assay was carried out with various bacterial genomic DNAs and O157-FHC1 and O157-FHC2 primers that amplified the region between base 23 and base 994 of the 2.7-kb PCR product. A single band at 970 bp was clearly detected in all of the strains of E. coli O157:H− and E. coli O157:H7 tested. However, no band was amplified from template DNAs from other bacteria, including both nonpathogenic and pathogenic E. coli except E. coli O157. All raw meats inoculated with E. coli O157:H7 at 3 × 100 to 3.5 × 102 CFU/25 g were positive both for our PCR assay after cultivation in mEC-N broth at 42°C for 18 h and for the conventional cultural method.
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GRAUMANN, GARY H., and RICHARD A. HOLLEY. "Inhibition of Escherichia coli O157:H7 in Ripening Dry Fermented Sausage by Ground Yellow Mustard." Journal of Food Protection 71, no. 3 (2008): 486–93. http://dx.doi.org/10.4315/0362-028x-71.3.486.
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Compounds generated by the enzymatic hydrolysis of glucosinolates naturally present in mustard powder are potently bactericidal against Escherichia coli O157:H7. Because E. coli O157:H7 can survive the dry fermented sausage manufacturing process, 2, 4, and 6% (wt/wt) nondeheated (hot) mustard powder or 6% (wt/wt) deheated (cold) mustard powder were added to dry sausage batter inoculated with E. coli O157:H7 at about 7 log CFU/g to evaluate the antimicrobial effectiveness of the powders. Reductions in E. coli O157:H7 populations, changes in pH and water activity (aw), effects on starter culture (Pediococcus pentosaceus and Staphylococcus carnosus) populations, and effects of mustard powder on sausage texture (shear) were monitored during ripening. Nondeheated mustard powder at 2, 4, and 6% in dry sausage (0.90 aw) resulted in significant reductions in E. coli O157:H7 (P &lt; 0.05) of 3.4, 4.4, and 6.9 log CFU/g, respectively, within 30 days of drying. During fermentation and drying, mustard powder did not affect P. pentosaceus and S. carnosus activity in any of the treatments. Extension of drying to 36 and 48 days reduced E. coli O157:H7 by &gt;5 log CFU/g in the 4 and 2% mustard powder treatments, respectively. The 6% deheated mustard powder treatment provided the most rapid reductions of E. coli O157:H7 (yielding &lt;0.20 log CFU/g after 24 days) by an unknown mechanism and was the least detrimental (P &lt; 0.05) to sausage texture.
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Çadırcı, Özgür, Ali Gücükoğlu, Göknur Terzi Güzel, Tolga Uyanık, Abdulaziz Abdulahi, and Mustafa Alişarlı. "Characterization and Antimicrobial-Resistance Profile of Escherichia coli O157 and O157: H7 Isolated from Modified Atmosphere Packaged Meat Samples." Turkish Journal of Agriculture - Food Science and Technology 5, no. 10 (2017): 1142. http://dx.doi.org/10.24925/turjaf.v5i10.1142-1147.1228.
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Shiga-like toxin producing Escherichia coli is still an important public issue which causes extremely dangerous health problems. This study was planned in order to examine the inhibitory effect of Modified Atmosphere Packaging application on E. coli O157 and O157: H7. The purposes of the present study were to detect E. coli O157 and O157: H7 strains from ground and cubed beef. A total of 100 MAP cattle meat products (50 minced meat, 50 meat cubes) were collected from the markets and butchers in Samsun province between May and October 2013. According to results, 1(1/50-2%) E. coli O157 and 1(1/50-2%) E. coli O157: H7 strains isolated from 50 ground beef samples, while 1 (1/50-2%) E. coli O157 strain was identified from 50 cubed beef samples. It was determined that E. coli O157 isolate obtained from the MAP ground beef carried stx1, stx2 genes; E. coli O157: H7 isolate carried stx1, stx2, eaeA and hylA genes while E. coli O157 isolate obtained from the MAP cubed meat only carried the stx2 gene. In antibiogram test, both E. coli O157 isolates were resistant to streptomycin and one E. coli O157: H7 isolate was resistant to streptomycin, cephalothin and tetracycline. As a consequence; in order to protect public health, products should be kept in proper hygienic and technical conditions during sale and storage and use of uncontrolled antibiotics should be avoided.
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Antaki-Zukoski, Elizabeth M., Xunde Li, Bruce Hoar, John M. Adaska, Barbara A. Byrne, and Edward R. Atwill. "Understanding the transmission dynamics of Escherichia coli O157:H7 super-shedding infections in feedlot cattle." PeerJ 9 (December 20, 2021): e12524. http://dx.doi.org/10.7717/peerj.12524.
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Background The presence of Escherichia coli O157:H7 (E. coli O157:H7) super-shedding cattle in feedlots has the potential to increase the overall number (bio-burden) of E. coli O157:H7 in the environment. It is important to identify factors to reduce the bio-burden of E. coli O157 in feedlots by clarifying practices associated with the occurrence of super-shedders in feedlot cattle. Methods The objective of this study is to (1) identify host, pathogen, and management risk factors associated with naturally infected feedlot cattle excreting high concentrations of E. coli O157:H7 in their feces and (2) to determine whether the ingested dose or the specific strain of E. coli O157:H7 influences a super-shedder infection within experimentally inoculated feedlot cattle. To address this, (1) pen floor fecal samples and herd parameters were collected from four feedlots over a 9-month period, then (2) 6 strains of E. coli O157:H7, 3 strains isolated from normal shedder steers and 3 strains isolated from super-shedder steers, were inoculated into 30 one-year-old feedlot steers. Five steers were assigned to each E. coli O157:H7 strain group and inoculated with targeted numbers of 102, 104, 106, 108, and 1010 CFU of bacteria respectively. Results In the feedlots, prevalence of infection with E. coli O157:H7 for the 890 fecal samples collected was 22.4%, with individual pen prevalence ranging from 0% to 90% and individual feedlot prevalence ranging from 8.4% to 30.2%. Three samples had E. coli O157:H7 levels greater than 104 MPN/g feces, thereby meeting the definition of super-shedder. Lower body weight at entry to the feedlot and higher daily maximum ambient temperature were associated with increased odds of a sample testing positive for E. coli O157:H7. In the experimental inoculation trial, the duration and total environmental shedding load of E. coli O157:H7 suggests that the time post-inoculation and the dose of inoculated E. coli O157:H7 are important while the E. coli O157:H7 strain and shedding characteristic (normal or super-shedder) are not. Discussion Under the conditions of this experiment, super-shedding appears to be the result of cattle ingesting a high dose of any strain of E. coli O157:H7. Therefore strategies that minimize exposure to large numbers of E. coli O157:H7 should be beneficial against the super-shedding of E. coli O157:H7 in feedlots.
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HARA-KUDO, Y., H. KONUMA, M. IWAKI, et al. "Potential Hazard of Radish Sprouts as a Vehicle of Escherichia coli O157:H7." Journal of Food Protection 60, no. 9 (1997): 1125–27. http://dx.doi.org/10.4315/0362-028x-60.9.1125.
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We studied the contamination of radish sprouts after exposure to Escherichia coli O157:H7-inoculated water in the laboratory. The edible parts, the cotyledons and hypocotyl, became heavily contaminated with E. coli O157:H7 when they were grown from seeds soaked in E. coli O157:H7-inoculated water. These same parts became contaminated with E. coli O157:H7 when their roots were dipped into E. coli O157:H7-inoculated water. These findings suggest that E. coli O157:H7 contamination in the edible parts of radish sprouts could pose a serious hazard if the seeds or hydroponic water are contaminated with the bacterium.
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Bach, S. J., R. P. Johnson, K. Stanford, and T. A. McAllister. "Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep." Canadian Journal of Animal Science 89, no. 2 (2009): 285–93. http://dx.doi.org/10.4141/cjas08083.
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Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms
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Cobbold, Rowland N., Dale D. Hancock, Daniel H. Rice, et al. "Rectoanal Junction Colonization of Feedlot Cattle by Escherichia coli O157:H7 and Its Association with Supershedders and Excretion Dynamics." Applied and Environmental Microbiology 73, no. 5 (2006): 1563–68. http://dx.doi.org/10.1128/aem.01742-06.
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ABSTRACT Feedlot cattle were observed for fecal excretion of and rectoanal junction (RAJ) colonization with Escherichia coli O157:H7 to identify potential “supershedders.” RAJ colonization and fecal excretion prevalences were correlated, and E. coli O157:H7 prevalences and counts were significantly greater for RAJ samples. Based on a comparison of RAJ and fecal ratios of E. coli O157:H7/E. coli counts, the RAJ appears to be preferentially colonized by the O157:H7 serotype. Five supershedders were identified based on persistent colonization with high concentrations of E. coli O157:H7. Cattle copenned with supershedders had significantly greater mean pen E. coli O157:H7 RAJ and fecal prevalences than noncopenned cattle. Cumulative fecal E. coli O157:H7 excretion was also significantly higher for pens housing a supershedder. E. coli O157:H7/E. coli count ratios were higher for supershedders than for other cattle, indicating greater proportional colonization. Pulsed-field gel electrophoresis analysis demonstrated that isolates from supershedders and copenned cattle were highly related. Cattle that remained negative for E. coli O157:H7 throughout sampling were five times more likely to have been in a pen that did not house a supershedder. The data from this study support an association between levels of fecal excretion of E. coli O157:H7 and RAJ colonization in pens of feedlot cattle and suggest that the presence of supershedders influences group-level excretion parameters. An improved understanding of individual and population transmission dynamics of E. coli O157:H7 can be used to develop preslaughter- and slaughter-level interventions that reduce contamination of the food chain.
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AL-NABULSI, ANAS A., TAREQ M. OSAILI, HEBA M. OBAIDAT, REYAD R. SHAKER, SADDAM S. AWAISHEH, and RICHARD A. HOLLEY. "Inactivation of Stressed Escherichia coli O157:H7 Cells on the Surfaces of Rocket Salad Leaves by Chlorine and Peroxyacetic Acid." Journal of Food Protection 77, no. 1 (2014): 32–39. http://dx.doi.org/10.4315/0362-028x.jfp-13-019.
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Because Escherichia coli O157:H7 has been frequently associated with many foodborne outbreaks caused by consumption of leafy greens (lettuce, spinach, and celery), this study investigated the ability of deionized water, chlorine, and peroxyacetic acid to detach or inactivate stressed and unstressed cells of E. coli O157:H7 contaminating the surfaces of rocket salad leaves. E. coli O157:H7 cells stressed by acid, cold, starvation, or NaCl exposure, as well as unstressed cells, were inoculated on the surfaces of rocket salad leaves at 4°C. The effectiveness of two sanitizers (200 ppm of chlorine and 80 ppm of peroxyacetic acid) and deionized water for decontaminating the leaves treated with stressed and unstressed E. coli O157:H7 were evaluated during storage at 10 or 25°C for 0.5, 1, 3, and 7 days. It was found that washing with 80 ppm of peroxyacetic acid was more effective and reduced unstressed and stressed cells of E. coli O157:H7 by about 1 log CFU per leaf on the leaves. There was no apparent difference in the ability of stressed and unstressed cells to survive surface disinfection with the tested agents. Treatments to reduce viable E. coli O157:H7 cells on rocket leaves stored at 25°C were more effective than when used on those stored at 10°C. Washing with peroxyacetic acid or chlorine solution did not ensure the safety of rocket leaves, but such treatments could reduce the likelihood of water-mediated transfer of E. coli O157:H7 during washing and subsequent processing.
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Locking, M., and J. Cowden. "Escherichia coli O157." BMJ 339, oct06 3 (2009): b4076. http://dx.doi.org/10.1136/bmj.b4076.
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Pennington, Hugh. "Escherichia coli O157." Lancet 376, no. 9750 (2010): 1428–35. http://dx.doi.org/10.1016/s0140-6736(10)60963-4.
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Wolfson, Eliza B., Johanna Elvidge, Amin Tahoun, et al. "The interaction of Escherichia coli O157 :H7 and Salmonella Typhimurium flagella with host cell membranes and cytoskeletal components." Microbiology 166, no. 10 (2020): 947–65. http://dx.doi.org/10.1099/mic.0.000959.
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Bacterial flagella have many established roles beyond swimming motility. Despite clear evidence of flagella-dependent adherence, the specificity of the ligands and mechanisms of binding are still debated. In this study, the molecular basis of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium flagella binding to epithelial cell cultures was investigated. Flagella interactions with host cell surfaces were intimate and crossed cellular boundaries as demarcated by actin and membrane labelling. Scanning electron microscopy revealed flagella disappearing into cellular surfaces and transmission electron microscopy of S. Typhiumurium indicated host membrane deformation and disruption in proximity to flagella. Motor mutants of E. coli O157:H7 and S. Typhimurium caused reduced haemolysis compared to wild-type, indicating that membrane disruption was in part due to flagella rotation. Flagella from E. coli O157 (H7), EPEC O127 (H6) and S. Typhimurium (P1 and P2 flagella) were shown to bind to purified intracellular components of the actin cytoskeleton and directly increase in vitro actin polymerization rates. We propose that flagella interactions with host cell membranes and cytoskeletal components may help prime intimate attachment and invasion for E. coli O157:H7 and S. Typhimurium, respectively.
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Sule, Ismaila, Mutiat Omokanye, Olutoyin Adekunle, et al. "Detection of uidA, stx1, and stx2 Genes in Escherichia coli O157:H7 Isolated from Cattle Faecal Matter and River Water." Alexandria Journal of Veterinary Sciences 78, no. 1 (2023): 1. http://dx.doi.org/10.5455/ajvs.136270.
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Cattle can harbour enterohaemorrhagic Escherichia coli O157:H7 serotype in their faecal matters. This study aimed to isolate E. coli O157:H7 from the intestinal digesta, cattle dungs and water; and assess the antibiotic susceptibility and production of shiga toxins by the isolates. The counts of viable bacteria and faecal coliforms in 13 each of intestinal digesta and cattle dung and the 12 water samples were determined using nutrient agar and Eosin methylene blue agar respectively. Sorbitol MacConkey agar (SMAC) was used to screen for E. coli O157:H7 among the 38 E. coli isolates. PCR amplification of uidA genes was used to authenticate the isolates as enterohaemorrhagic E. coli O157:H7 serotype while amplification of stx1 and stx2 showed the production of shiga toxins. The antibiotic susceptibility patterns of the isolates were determined using standard disk diffusion method. The count of viable bacteria and faecal coliform was highest in the intestinal digesta followed by cattle dungs. There was 100% susceptibility to ofloxacin coupled with 100% resistant to augmentin by all the 8 E. coli O157 and 10 non-O157 isolates. The E. coli O157 isolates were more susceptible to ciprofloxacin, gentamicin, ampicillin and cefuroxime than non-O157 isolates but were less susceptible to nitrofurantoin and ceftazidime than non-O157. Eight (44.4%) out of the 18 presumptive E. coli O157 on SMAC amplified uidA genes and were confirmed as E. coli O157. They were isolated only from intestinal digesta and cattle dung. The prevalence of stx1 and stx2 genes among the E. coli O157 was 37.5% and 12.5% respectively. It is concluded from this study that intestinal digesta and cattle dung harboured E. coli O157: H7 some of which possessed shiga toxin.
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THAMPURAN, NIRMALA, A. SURENDRARAJ, and P. K. SURENDRAN. "Prevalence and Characterization of Typical and Atypical Escherichia coli from Fish Sold at Retail in Cochin, India." Journal of Food Protection 68, no. 10 (2005): 2208–11. http://dx.doi.org/10.4315/0362-028x-68.10.2208.
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Escherichia coli is a common contaminant of seafood in the tropics and is often encountered in high numbers. The count of E. coli as well as verotoxigenic E. coli O157:H7 was estimated in 414 finfish samples composed of 23 species of fresh fish from retail markets and frozen fish from cold storage outlets in and around Cochin, India. A total of 484 presumptive E. coli were isolated, and their indole–methyl red–Voges-Proskauer–citrate (IMViC) pattern was determined. These strains were also tested for labile toxin production by a reverse passive latex agglutination method and checked for E. coli serotype O157 by latex agglutination with O157-specific antisera. Certain biochemical marker tests, such as methylumbelliferyl-β-glucuronide (MUG), sorbitol fermentation, decarboxylase reactions, and hemolysis, which are useful for screening pathogenic E. coli, were also carried out. Results showed that 81.4% of the E. coli isolates were sorbitol positive. Among this group, 82% were MUG positive, and 14.46% of the total E. coli isolates showed human blood hemolysis. None of the isolates were positive for agglutination with E. coli O157 antisera nor did any produce heat-labile enterotoxin. This study indicates that typical E. coli O157 or labile toxin–producing E. coli is absent in the fish and fishery environments of Cochin (India). However, the presence of MUG and sorbitol-negative strains that are also hemolytic indicates the existence of aberrant strains, which require further investigation.
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Abebe, Engidaw, Getachew Gugsa, Meselu Ahmed, et al. "Occurrence and antimicrobial resistance pattern of E. coli O157:H7 isolated from foods of Bovine origin in Dessie and Kombolcha towns, Ethiopia." PLOS Neglected Tropical Diseases 17, no. 1 (2023): e0010706. http://dx.doi.org/10.1371/journal.pntd.0010706.
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E. coli are frequently isolated food-borne pathogens from meat, milk, and their products. Moreover, there has been a significant rise in the antimicrobial resistance patterns of E. coli O157:H7 to commonly used antibiotics. A cross-sectional study was conducted from October 2019 to July 2021 to estimate prevalence and identify associated factors of E. coli and E. coli O157:H7 and to determine antibiotic resistance pattern of E. coli O157:H7 from foods of bovine origin in Dessie and Kombolcha towns. A total of 384 samples were collected. Systematic and simple random sampling techniques were employed for sampling carcasses and milking cows, respectively. E. coli and E. coli O157:H7 were detected according to recommended bacteriological protocols. E. coli O157:H7 strains were evaluated for in vitro antimicrobial susceptibility using agar disk diffusion method. Both descriptive and inferential statistical techniques were applied to analyze the data. Overall prevalence rates of E. coli and E. coli O157:H7 were 54.7% and 6.5%, respectively. Highest prevalence rates of E. coli (79.6%) and E. coli O157:H7 (16.7%) were obtained from carcass swabs and milk tank samples, respectively. Unlike E. coli O157:H7, a statistically significant difference in the E. coli prevalence (P<0.05) was observed among the different sample types. Multidrug resistance was observed among all isolates of E. coli O157:H7. All E. coli O157:H7 isolates (100.0%) were susceptible to Ampicillin, Sulfamethoxazole-trimethoprim, and Norfloxacin. On the contrary, all of the isolates (100%) were resistant to Penicillin G, Vancomycin, and Oxacillin. The current study indicated that different foods of bovine origin in the study area were unsafe for human consumption. Hence, good hygienic production methods should be employed to ensure the safety of foods of bovine origin.
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MIZAN, SHAIKH, MARGIE D. LEE, BARRY G. HARMON, SUZANA TKALCIC, and JOHN J. MAURER. "Acquisition of Antibiotic Resistance Plasmids by Enterohemorrhagic Escherichia coli O157:H7 within Rumen Fluid." Journal of Food Protection 65, no. 6 (2002): 1038–40. http://dx.doi.org/10.4315/0362-028x-65.6.1038.
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The emergence of antibiotic resistance among important foodborne pathogens like Escherichia coli O157:H7 has become an important issue with regard to food safety. In contrast to the case for Salmonella, antibiotic resistance has been slow in its development in E. coli O157:H7 despite the presence of mobile antibiotic resistance genes in other E. coli organisms that inhabit the same animal host. We set out to determine if rumen fluid influences the transfer of plasmid-mediated, antibiotic resistance to E. coli O157:H7. A commensal E. coli strain from a dairy cow was transformed with conjugative R plasmids and served as the donor in matings with naladixic acid–resistant E. coli O157:H7. R plasmids were transferred from the donor E. coli strain to E. coli O157:H7 in both Luria-Bertani (LB) broth and rumen fluid. R plasmids were transferred at a higher frequency to E. coli O157:H7 during 6 h of incubation in rumen fluid at rates comparable to those in LB broth, indicating that conditions in rumen fluid favor the transfer of the plasmids to E. coli O157. This finding suggests that the cow's rumen is a favorable environment for the genetic exchange of plasmids between microflora and resident E. coli O157:H7 in the bovine host.
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KIM, JIN KYUNG, and MARK A. HARRISON. "Surrogate Selection for Escherichia coli O157:H7 Based on Cryotolerance and Attachment to Romaine Lettuce." Journal of Food Protection 72, no. 7 (2009): 1385–91. http://dx.doi.org/10.4315/0362-028x-72.7.1385.
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Using nonpathogenic surrogates in place of pathogens when evaluating commercial food processing operations offers safety advantages, but their usefulness may be limited if they do not behave in the same manner in challenge situations. Nonpathogenic Escherichia coli strains were compared with E. coli O157:H7 based on cryotolerance, cell surface characteristics (hydrophobicity, zeta potential, and morphology), and attachment to lettuce. Populations for all strains were reduced less than 1 log CFU/ml over 7 days of storage at −18°C. After 1 day of storage, the survival rate for E. coli ATCC 25922 was 44.3%, similar to that of E. coli O157:H7 (49%). No capsule was produced by any of the strains. E. coli O157:H7 expressed curli at both 20 and 37°C, whereas E. coli ATCC 25922 expressed curli only when grown at 20°C. Hydrophobicity of E. coli ATCC 25922 was 53.5%, similar to that of E. coli O157:H7 (56.2%). The zeta potentials of nonpathogenic E. coli and E. coli O157: H7 cells were −4.95 to −10.92 mV. The zeta potential of E. coli ATCC 25922 was not significantly different (P &gt; 0.05) from that of E. coli O157:H7 at 37°C and was the closest value to that of E. coli O157:H7 at 20°C. E. coli ATCC 25922 exhibited the greatest attachment to lettuce among the surrogates and was not significantly different from E. coli O157:H7 (P &gt; 0.05). Based on cryotolerance and cell surface characteristics, E. coli ATCC 25922 is a useful surrogate for E. coli O157: H7 for studies involving attachment to fresh produce.
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Antaki-Zukoski, Elizabeth, Xunde Li, Patricia Pesavento, Tran Nguyen, Bruce Hoar, and Edward Atwill. "Comparative Pathogenicity of Wildlife and Bovine Escherichia coli O157:H7 Strains in Experimentally Inoculated Neonatal Jersey Calves." Veterinary Sciences 5, no. 4 (2018): 88. http://dx.doi.org/10.3390/vetsci5040088.
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Shiga toxin-producing Escherichia coli, like E. coli O157:H7, are important human and animal pathogens. Naturally-acquired E. coli O157:H7 infections occur in numerous species but, particularly, cattle have been identified as a significant reservoir for human cases. E. coli O157:H7 are isolated from a number of domestic and wild animals, including rodents that share a living space with cattle. These Shiga toxin-producing E. coli O157:H7 strains can be highly virulent in humans, but little is known about the sequelae of interspecies transfer. In a group of neonatal calves, we determined the differences in colonization patterns and lesions associated with infection using either a wildlife or bovine E. coli O157:H7 strain. In calves challenged with the wildlife E. coli O157:H7 strain, the large (descending) colon was solely colonized, which differed substantially from the calves inoculated with the bovine E. coli O157:H7 strain, where the spiral colon was the principal target of infection. This study also demonstrated that while both interspecies- and intraspecies-derived E. coli O157:H7 can infect young calves, the distribution and severity differs.
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GÓMEZ-ALDAPA, CARLOS A., CLAUDIO A. DÍZ-CRUZ, JORGE F. CERNA-CORTES, et al. "Escherichia coli O157 in Ground Beef from Local Retail Markets in Pachuca, Mexico." Journal of Food Protection 76, no. 4 (2013): 680–84. http://dx.doi.org/10.4315/0362-028x.jfp-12-348.
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Escherichia coli O157 strains have been recognized as pathogenic bacteria, of which raw beef is a known vehicle. An evaluation was done of the presence of E. coli O157 in ground beef from local retail markets in Pachuca, Hidalgo State, Mexico. A total of 120 ground beef samples (500 g) were tested for E. coli O157 by simultaneous application of the U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS)'s Microbiology Laboratory Guidebook culture procedure 5.05, and two commercial kits, Reveal for E. coli O157:H7 and Visual Immunoprecipitate Assay (VIP) Gold for enterohemorrhagic E. coli. Two incubation times (8 and 20 h) were used with the commercial kits. Presence of stx1, stx2, and eaeA loci was determined by multiplex PCR. Of 360 subsamples (120 per procedure), 12 samples were found to be E. coli O157 positive by the FSIS culture method. With VIP, 73 subsamples were presumptive positive after 8 h of enrichment, and 60 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed true positives with the FSIS method. With Reveal, 60 subsamples were presumptive positive after 8 h of enrichment and 50 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed as true positives with the FSIS method. A total of 57 E. coli O157:H7 and 21 E. coli O157 strains were isolated. None of the O157 or O157:H7 strains had stx1 or stx2 loci, and only one had the eaeA locus. To our knowledge, this is the first report of the presence of E. coli O157 in commercial ground beef from Mexico, and the first report of isolation of a large number of stx-negative E. coli O157 and E. coli O157:H7 strains in Mexico.
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Heijnen, Leo, and Gertjan Medema. "Quantitative detection of E. coli, E. coli O157 and other shiga toxin producing E. coli in water samples using a culture method combined with real-time PCR." Journal of Water and Health 4, no. 4 (2006): 487–98. http://dx.doi.org/10.2166/wh.2006.0032.
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Recent water related outbreaks of shiga toxin producing E. coli O157 have resulted in increased attention of the water industry to this potentially deadly pathogen. Current methods to detect E. coli O157 and its virulence genes are laborious and time-consuming. Specificity, sensitivity and simple use of a real-time PCR method makes it an attractive alternative for the detection of STEC E. coli O157. This study describes the development and application of real-time PCR methods for the detection of E. coli O157, shiga toxin genes (Stx1 and Stx2) and E. coli. The specificity of the methods was confirmed by performing colony-PCR assays on characterized bacterial isolates, demonstrating the applicability of these assays as rapid tests to confirm the presence of E. coli or E. coli O157 colonies on culture plates. Sensitive culture-PCR methods were developed by combining culture enrichment with real-time PCR detection. This rapid method allowed detection of low concentrations of E. coli O157 in the presence of high concentrations of non-O157-E. coli (1:104). Culture-PCR methods were applied to 27 surface water and 4 wastewater samples. E. coli O157 and both Stx genes were detected in two wastewater samples, whereas only E. coli O157 was detected in two surface water samples. Culture-PCR methods were not influenced by matrix effects and also enabled quantitative (MPN) detection of E. coli in these samples.
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Navarro, Armando, Carlos Eslava, Guadalupe García de la Torre, et al. "Common epitopes in LPS of different Enterobacteriaceae are associated with an immune response against Escherichia coli O157 in bovine serum samples." Journal of Medical Microbiology 56, no. 11 (2007): 1447–54. http://dx.doi.org/10.1099/jmm.0.47201-0.
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Epidemiological studies in both humans and animals conducted in Mexico have shown that the isolation frequency of Escherichia coli O157 : H7 is low. In a previous study, IgG antibodies against E. coli O157, O7 and O116 LPS were found in serum samples from children and adults with no previous history of E. coli O157 : H7 infection. The present study was designed to determine whether a similar immune response against E. coli O157 : H7 and other antigenically related bacteria was present in bovine serum samples. A total of 310 serum samples from different herds in Mexico was analysed by microagglutination assays against different enterobacterial antigens, including E. coli O157. Microagglutination assays were positive against E. coli O7 (55 %), O116 (76 %) and O157 (36 %), Escherichia hermannii (15 %), Salmonella enterica serotype Urbana (14 %) and Salmonella enterica subsp. arizonae (40 %). These results were confirmed using a specific ELISA with purified LPS. A positive reaction was observed against the LPS of E. coli O7 (29 %), O116 (12 %) and O157 (22 %), E. hermannii (4 %), Salmonella Urbana (13 %) and S. enterica subsp. arizonae (12 %). Serum absorption studies of positive serum samples indicated the existence of at least three common epitopes shared by the LPS of E. coli O7, O116 and O157, and two others between E. coli O157 and Salmonella Urbana and S. enterica subsp. arizonae. A bactericidal assay against E. coli O157 : H7 using 31 bovine serum samples was performed, and 22 (71 %) of these serum samples gave positive results. The data demonstrated that bovine serum showed a response against different enterobacteria, including E. coli O157, and that this response could be due to the presence of shared epitopes in the LPS of these organisms.
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DeCory, Thomas R., Richard A. Durst, Scott J. Zimmerman, et al. "Development of an Immunomagnetic Bead-Immunoliposome Fluorescence Assay for Rapid Detection of Escherichia coli O157:H7 in Aqueous Samples and Comparison of the Assay with a Standard Microbiological Method." Applied and Environmental Microbiology 71, no. 4 (2005): 1856–64. http://dx.doi.org/10.1128/aem.71.4.1856-1864.2005.
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ABSTRACT The objective of this study was to develop and optimize a protocol for the rapid detection of Escherichia coli O157:H7 in aqueous samples by a combined immunomagnetic bead-immunoliposome (IMB/IL) fluorescence assay. The protocol consisted of the filtration or centrifugation of 30- to 100-ml samples followed by incubation of the filter membranes or pellet with anti-E. coli O157:H7 immunomagnetic beads in growth medium specific for E. coli O157:H7. The resulting E. coli O157:H7-immunomagnetic bead complexes were isolated by magnetic separation, washed, and incubated with sulforhodamine B-containing immunoliposomes specific for E. coli O157:H7; the final immunomagnetic bead-E. coli O157:H7-immunoliposome complexes were again isolated by magnetic separation, washed, and lysed with a n-octyl-β-d-glucopyranoside to release sulforhodamine B. The final protocol took less than 8 h to complete and had a detection limit of less than 1 CFU of E. coli O157:H7 per ml in various aqueous matrices, including apple juice and cider. To validate the protocol at an independent facility, 100-ml samples of groundwater with and without E. coli O157:H7 (15 CFU) were analyzed by a public health laboratory using the optimized protocol and a standard microbiological method. While the IMB/IL fluorescence assay was able to identify E. coli O157:H7-containing samples with 100% accuracy, the standard microbiological method was unable to distinguish E. coli O157:H7-spiked samples from negative controls without further extensive workup. These results demonstrate the feasibility of using immunomagnetic beads in combination with sulforhodamine B-encapsulating immunoliposomes for the rapid detection of E. coli O157:H7 in aqueous samples.
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Hara-Kudo, Y., M. Ikedo, H. Kodaka, et al. "Selective Enrichment with a Resuscitation Step for Isolation of Freeze-Injured Escherichia coli O157:H7 from Foods." Applied and Environmental Microbiology 66, no. 7 (2000): 2866–72. http://dx.doi.org/10.1128/aem.66.7.2866-2872.2000.
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ABSTRACT We studied injury of Escherichia coli O157:H7 cells in 11 food items during freeze storage and methods of isolating freeze-injured E. coli O157:H7 cells from foods. Food samples inoculated with E. coli O157:H7 were stored for 16 weeks at −20�C in a freezer. Noninjured and injured cells were counted by using tryptic soy agar and sorbitol MacConkey agar supplemented with cefixime and potassium tellurite. Large populations of E. coli O157:H7 cells were injured in salted cabbage, grated radish, seaweed, and tomato samples. In an experiment to detectE. coli O157:H7 in food samples artificially contaminated with freeze-injured E. coli O157:H7 cells, the organism was recovered most efficiently after the samples were incubated in modifiedE. coli broth without bile salts at 25�C for 2 h and then selectively enriched at 42�C for 18 h by adding bile salts and novobiocin. Our enrichment method was further evaluated by isolating E. coli O157:H7 from frozen foods inoculated with the organism prior to freezing. Two hours of resuscitation at 25�C in nonselective broth improved recovery of E. coliO157:H7 from frozen grated radishes and strawberries, demonstrating that the resuscitation step is very effective for isolating E. coli O157:H7 from frozen foods contaminated with injured E. coli O157:H7 cells.
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Aminudin, Muhammad Rizki, Denny Widaya Lukman, Mirnawati Bachrum Sudarwanto, and Herwin Pisestyani. "Escherichia coli O157:H7 Bacteria Antibiotic Resistant Isolated from Flies at Food Courts in IPB Dramaga Campus." Jurnal Sain Veteriner 42, no. 3 (2024): 345. https://doi.org/10.22146/jsv.99843.
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Several human and animal pathogens transmit into the food chain through houseflies as mechanical vectors, one of which is E. coli O157:H7. E. coli O157:H7 can express Shiga toxin (Stx) which can cause diarrhea, hemorrhagic colitis, and potentially fatal hemolytic-uremic syndrome (HUS) in humans. Some pathogen strains show resistance against various antibiotics, causing complex health problems. This study aims to analyze the presence of antibiotic-resistant E. coli O157:H7 bacteria carried by houseflies (M. domestica) in the food court IPB Dramaga campus area. Detection of E. coli O157:H7 on fly legs using qPCR method based on MU 7.2.3.32-8. E. coli O157:H7 isolates were tested for sensitivity to the antibiotic’s ciprofloxacin, ampicillin, tetracycline, trimethoprim-sulfamethoxazole, cefepime, chloramphenicol, ceftazidime, cefotaxime, and ceftriaxone using the Kirby Bauer disc diffusion method. This study isolated 5 E. coli isolates (5/40; 12.5%), and 2 of them were confirmed as E. coli O157:H7. One isolate of E. coli O157:H7 was resistant against ampicillin and tetracycline, and one isolate was resistant against ampicillin, tetracycline, trimethoprim-sulfamethoxazole, and ceftazidime. The multi-drug resistance was identified only in 1 isolate of E. coli O157:H7.Houseflies collected from the food court have the potential to transmit antibiotic-resistant E. coli O157:H7 around the IPB campus.
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Reinstein, S., J. T. Fox, X. Shi, and T. G. Nagaraja. "Prevalence of Escherichia coli O157:H7 in Gallbladders of Beef Cattle." Applied and Environmental Microbiology 73, no. 3 (2006): 1002–4. http://dx.doi.org/10.1128/aem.02037-06.
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ABSTRACT Gallbladders and rectal contents were collected from cattle (n = 933) at slaughter to determine whether the gallbladder harbors Escherichia coli O157:H7. Both gallbladder mucosal swabs and homogenized mucosal tissues were used for isolation. Only five gallbladders (0.54%) were positive for E. coli O157:H7. Fecal prevalence averaged 7.1%; however, none of the cattle that had E. coli O157:H7 in the gallbladder was positive for E. coli O157:H7 in feces. Therefore, the gallbladder does not appear to be a common site of colonization for E. coli O157:H7 in beef cattle.
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Müller, E. E., M. B. Taylor, W. O. K. Grabow, and M. M. Ehlers. "Isolation and characterization of Escherichia coli O157:H7 and shiga toxin-converting bacteriophages from strains of human, bovine and porcine origin." Water Supply 2, no. 3 (2002): 29–38. http://dx.doi.org/10.2166/ws.2002.0082.
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Toxin-converting bacteriophages encoding the Stx2 gene were induced from strains of Escherichia coli O157:H7 isolated from sewage, bovine and porcine faeces. Toxin synthesis can be stimulated by the induction of integrated toxin-converting phages from the host E. coli O157:H7 organism by ultra-violet (UV) exposure. The UV-mediated DNA damage of E. coli O157:H7 triggers a bacterial SOS response resulting in phage release. Free ranging phages outside their E. coli O157:H7 hosts were detected but could not be isolated directly from environmental samples such as sewage and river water. E. coli O157:H7 colonies carrying the genes coding for Stx2 were isolated from 1 sewage sample (0.76% of positive samples), 8 cattle faecal samples (16.67% of positive samples) and 2 pig faecal samples (14.28% of positive samples). Characterization of E. coli O157:H7 was done by repetitive sequence analysis using ERIC-PCR to determine the relationships between the individual E. coli O157:H7 strains. The ERIC-PCR analysis revealed distinct patterns for all E. coli O157:H7 strains with some small differences between the strains. DNA sequencing of some of the E. coli O157:H7 positive isolates carrying the Stx2 genes were performed confirming the amplified DNA nucleotide sequences of Stx2. Electron microscopic analysis revealed, for the first time in South Africa, that Stx2-converting phages induced from E. coli O157:H7 have different morphologies to that of phage lambda which was previously described. The role of the induced integrated Stx2 phages in natural environments such as river and dam water remains unclear. With the induction of Stx2-converting phages from environmental E. coli O157:H7 isolates, it is now possible to determine the potential of these phages to convert non-pathogenic E. coli strains and other enterobacteriaciae into pathogenic strains.
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Ariyanti, T., F. Rachmawati, SM Noor, and Suhaemi. "Contamination of Escherichia coli O157:H7 in Milk and Its Dairy Products in Depok, Cianjur, Sukabumi and Bandung." IOP Conference Series: Earth and Environmental Science 1107, no. 1 (2022): 012047. http://dx.doi.org/10.1088/1755-1315/1107/1/012047.
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Abstract Escherichia coli O157:H7 is known as a foodborne pathogen that can infect humans as well as animals. Dairy cows are the main reservoir of E. coli O157:H7 strains. These bacteria have the potential to pollute milk through direct contact with cattle and the dairy farming environment. Bacteria can survive during the production process and dairy products such as cheese. The presence of E. coli O157:H7 in dairy products has not been widely reported in Indonesia. The purpose of this study was to examine E. coli O157:H7 in the fresh milk from livestock and dairy products obtained from supermarkets and traditional markets in Depok, Cianjur, Sukabumi, and Bandung. A conventional method for E. coli isolation and testing techniques and serotyping tests on O157 and H7 was used in the study. The results showed that 26 isolates (23.85%) of a total of 109 fresh milk samples were positive for E. coli. They were identified as E. coli O157:H7 were 17 (65.38%) of 26 E. coli isolates. In dairy products, E. coli O157:H7 was not detected. This indicates that biosafety and biosecurity in the of dairy cows need to be to prevent E. coli O157:H7 contamination in milk and their livestock environment.
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JUNG, BYEONG YEAL, SUK CHAN JUNG, and CHANG HEE KWEON. "Development of a Rapid Immunochromatographic Strip for Detection of Escherichia coli O157." Journal of Food Protection 68, no. 10 (2005): 2140–43. http://dx.doi.org/10.4315/0362-028x-68.10.2140.
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We developed an immunochromatographic (IC) strip for the rapid detection of Escherichia coli O157 in enriched samples. Murine monoclonal antibody to E. coli O157:H7 lipopolysaccharide was conjugated with 40 nm of colloidal gold particles by the citrate method. The specificity of the IC strip was determined using 48 pure-cultured bacteria, including 32 E. coli strains and 16 non–E. coli strains. Regardless of H serotype, E. coli O157 strains produced a positive signal, whereas the others, representing 29 E. coli serotypes, did not. Among 16 non–E. coli strains, only Citrobacter amalonaticus yielded a positive signal. The sensitivity of the IC strip was determined using 10-fold diluted E. coli O157:H7, with a range of 1.8 × 107 to 1.8 CFU/ml in enriched raw beef. E. coli O157 could be detected at a minimum of 1.8 × 105 CFU/ml without enrichment and 1.8 CFU/ml after enrichment. Various samples were enriched to detect E. coli O157 using the IC strip and to isolate E. coli O157:H7 using traditional culture procedures. The IC strip test results exhibited 100% agreement with traditional methods after selective enrichment, since E. coli O157:H7 was also isolated from all the samples with positive strip test results. However, the specificity of the strip was somewhat higher with pork (98.8%) than with bovine feces (87.9%) and swine feces (93.4%). These results indicated that the IC strip exhibits high specificity and sensitivity in the detection of E. coli O157, and this assay is rapid, economical, and simple, without requirement of complicated equipment.
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LeJeune, Jeffrey T., Thomas E. Besser, and Dale D. Hancock. "Cattle Water Troughs as Reservoirs ofEscherichia coli O157." Applied and Environmental Microbiology 67, no. 7 (2001): 3053–57. http://dx.doi.org/10.1128/aem.67.7.3053-3057.2001.
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ABSTRACT Environmental survival of Escherichia coli O157 may play an important role in the persistence and dissemination of this organism on farms. The survival of culturable and infectious E. coli O157 was studied using microcosms simulating cattle water troughs. Culturable E. coli O157 survived for at least 245 days in the microcosm sediments. Furthermore, E. coli O157 strains surviving more than 6 months in contaminated microcosms were infectious to a group of 10-week-old calves. Fecal excretion ofE. coli O157 by these calves persisted for 87 days after challenge. Water trough sediments contaminated with feces from cattle excreting E. coli O157 may serve as a long-term reservoir of this organism on farms and a source of infection for cattle.
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BLAIS, BURTON W., RONALD A. BOOTH, LUCILLE PHILLIPPE, SITHIAN PANDIAN, and HIROSHI YAMAZAKI. "Polymacron™ Enzyme Immunoassay System for Detection of Escherichia coli O157 Inoculated into Foods†." Journal of Food Protection 60, no. 2 (1997): 98–101. http://dx.doi.org/10.4315/0362-028x-60.2.98.
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A rapid and simple enzyme immunoassay system was developed for detection of the food-borne pathogen Escherichia coli O157. This system is based on the use of anti-E. coli O157 antibody-coated Polymacron™, an inexpensive macroporous polyester fabric, as a high-surface-area immunoadsorbent for the rapid capture and subsequent immunoenzymatic detection of E. coli O157 antigens extracted from test samples by heating at 100°C for 10 min in the presence of sodium cholate. A dot blot format was used which facilitated the assay of multiple samples. The method was specific for all strains tested bearing the O157 and related antigens (e.g., group N Salmonella), giving positive reactions in the assay of pure cultures of 29 E. coli O157:H7 strains, one E. coli O157:H12, one E. coli O157:NM (nonmotile) and one Salmonella urbana strain, but not in the assay of a variety of other gram-negative and gram-positive bacteria. The method permitted the detection of ca. 400 E. coli O157:H7 CFU in a 5-μl spot applied to Polymacron™, and of as few as 0.4 CFU of E. coli O157:147 cells per g inoculated into ground beef samples, which were assayed after overnight enrichment.
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Rosyidi, Anwar. "DETEKSI Escherichia coli SUMBER AYAM KAMPUNG DAN RESISTENSINYA TERHADAP BERBAGAI ANTIBIOTIK." Maduranch : Jurnal Ilmu Peternakan 3, no. 1 (2008): 17. https://doi.org/10.53712/maduranch.v3i1.342.
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Escherichia coli serotipe O157:H7 dapat menyebabkan terjadinya haemorrhagic colitis (HC) pada manusia dengan gejala spesifik terjadinya diare berdarah. Pada beberapa pasien selain menyebabkan haemorrhagic colitis (HC), E. coli serotipe O157:H7 dapat juga menyebabkan terjadinya haemolytic uremic syndrome (HUS), thrombocytopenia purpura (TPP) yang menyerang syaraf pusat. Tujuan penelitian ini adalah untuk mendeteksi keberadaan dan prevalensi E. coli O157:H7 dan E. coli pada ayam kampung, serta menguji resistensinyanya terhadap antibiotik. Untuk menentukan bakteri yang diperoleh merupakan Escherichia coli O157:H7, 30 usus ayam kampung yang diambil dari tempat pemotongan di pasar tradisional Mataram, kemudian isi usus dikultur pada media Fluorocult agar untuk Escherichia coli O157:H7. Pada media Fluorocult, Escherichia coli O157:H7 yang disinari lampu UV tidak terlihat fluoresen atau pendaran, sedangkan E. coli strain lainnya akan terlihat berpendar. Bakteri Escherichia coli yang diperoleh diuji sentivitasnya terhadap 4 antibiotik. Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa bakteri Escherichia coli terdeteksi 100% pada feses ayam kampung namun Escherichia coli O157:H7 tidak terdeteksi (0%). Escherichia coli sumber ayam kampung mempunyai pola resistensi terhadap antibiotik yang tertinggi terhadap ampisilin, diikuti tetrasiklin, kloramfenikol dan terendah terhadap ciprofloksasin. Escherichia coli sumber ayam kampung ditemukan kasus multiple drugs resintance atau resistensi lebih dari satu jenis antibiotik yakni terhadap ampisilin dan tetrasiklin.