Abundance and characteristics of the recreational water quality indicator bacteria Escherichia coli and enterococci in gull faeces

AIMS: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal indicator bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. METHODS AND RESULTS: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (Vitek GNI+) and enterococci (API rapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at >/=85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus API(R) profiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. CONCLUSIONS: Gull faeces could be a major contributor of E. coli (10(5)-10(9) CFU g(-1)) and enterococci (10(4)-10(8) CFU g(-)1) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. SIGNIFICANCE AND IMPACT OF THE STUDY: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.     

Antibiotic resistant bacteria in Windermere and two remote upland tarns in the English Lake District

The incidence of antibiotic resistance was determined in over 2000 bacteria which were divided into the following groups: faecal streptococci, coliforms (excluding Escherichia coli), E. coli, Pseudomonas spp. and aquatic bacteria (i.e. bacteria predominant in the lake water which were excluded from the previous four categories). The isolates were obtained from the water of Windermere (English Lake District) and from a sewage effluent which entered the lake. With the exception of the faecal streptococci, the incidence of antibiotic resistance was higher in the bacteria isolated from the lake water than in those from the effluent, and ranked according to groups Pseudomonas spp. greater than E. coli greater than aquatic bacteria greater than coliforms greater than faecal streptococci. The highest incidence of multiple resistance was found among the pseudomonads. When corrected for the relative size of each population the pool of antibiotic resistance in the aquatic bacteria was by far the largest. The incidence of antibiotic resistance in aquatic bacteria isolated from Windermere was, however, lower than in those isolated from two remote upland tarns. This finding may have been due to differences in the species composition of the three sites except that the same results were obtained when only fluorescent pseudomonads were tested. The upland tarns were not totally isolated from man and other animals but did not receive any sewage or other effluents and therefore the results were surprising. Possible explanations include a lack of susceptibility in aquatic bacteria and increased resistance associated with growth in nutrient poor environments.     

The role of visible faecal material as a vehicle for generic Escherichia coli,coliform, and other enterobacteria contaminating poultry carcasses during slaughtering

AIMS: A comparison of Enterobacteriaceae, coliform and Escherichia coli counts in chicken carcasses with and without visible faecal contamination was conducted to evaluate the role of contamination as a vehicle for generic E. coli, coliform and other enterobacteria contaminating broiler chicken carcasses when processed under routine commercial operations. METHODS AND RESULTS: Samples were removed from the processing line immediately after evisceration, inside-outside shower and chilling for microbiological analysis. After evisceration, mean counts were significantly different only for E. coli (P < or = 0.05) in chicken carcasses with and without visible faecal contamination. While the spray wash practice was not efficient enough for complete removal of the visible contamination from carcasses, leading to microbiological reduction percentages lower than expected, 25 ppm chlorinated water chilling did reduce the contamination level considerably in all samples. CONCLUSIONS: Carcasses with and without visible faecal contamination harboured E. coli and other potentially hazardous enterobacteria. E. coli was the predominant strain isolated in all samples, Enterobacter cloacae being next most frequent. SIGNIFICANCE AND IMPACT OF THE STUDY: The zero tolerance of visible faecal contamination requirement alone is not sufficient to assure safety and to improve the microbial quality of carcasses.     

Antibiotic resistant bacteria in Windermere and two remote upland tarns in the English Lake District

The incidence of antibiotic resistance was determined in over 2000 bacteria which were divided into the following groups: faecal streptococci, coliforms (excluding Escherichia coli ), E. coli, Pseudomonas spp. and aquatic bacteria (i.e. bacteria predominant in the lake water which were excluded from the previous four categories). The isolates were obtained from the water of Windermere (English Lake District) and from a sewage effluent which entered the lake. With the exception of the faecal streptococci, the incidence of antibiotic resistance was higher in the bacteria isolated from the lake water than in those from the effluent, and ranked according to groups Pseudomonas spp. > E. coli > aquatic bacteria > coliforms > faecal streptococci. The highest incidence of multiple resistance was found among the pseudomonads. When corrected for the relative size of each population the pool of antibiotic resistance in the aquatic bacteria was by far the largest. The incidence of antibiotic resistance in aquatic bacteria isolated from Windermere was, however, lower than in those isolated from two remote upland tarns. This finding may have been due to differences in the species composition of the three sites except that the same results were obtained when only fluorescent pseudomonads were tested. The upland tarns were not totally isolated from man and other animals but did not receive any sewage or other effluents and therefore the results were surprising. Possible explanations include a lack of susceptibility in aquatic bacteria and increased resistance associated with growth in nutrient poor environments.     

Bacteriological studies on Iraqi milk products.

Samples from different types of domestic milk products including cheese, kishfa and gaymer were assessed for bacteriological quality over a 4-month period. A total of 400 samples were randomly selected across Mosul city and tested for faecal coliform counts, enteropathogenic Escherichia coli (EPEC) and enterotoxigenic E. coli (ETEC). Faecal coliforms were present at levels greater than 10(2) cfu/g in 72.5% and less than 10(2) cfu/g in 27.5% of samples. Of the 430 E. coli strains isolated from the 400 samples of milk products, 138 were serotypes of EPEC. These were found in 81 (40.5%) samples of cheese, 35 (23.8%) of kishfa and 22 (29.7%) of gaymer. During this period, 26 strains of ETEC were also isolated, all of which demonstrated heat-labile or heat-stable toxins. The high proportion of strains of three groups of E. coli showing resistance to antibiotics is discussed in relation to widespread use of antibiotics and the possible public health implication.     

Resistance determinants of a highly arsenic-resistant strain of Leptospirillum ferriphilum isolated from a commercial biooxidation tank

Two sets of arsenic resistance genes were isolated from the highly arsenic-resistant Leptospirillum ferriphilum Fairview strain. One set is located on a transposon, TnLfArs, and is related to the previously identified TnAtcArs from Acidithiobacillus caldus isolated from the same arsenopyrite biooxidation tank as L. ferriphilum. TnLfArs conferred resistance to arsenite and arsenate and was transpositionally active in Escherichia coli. TnLfArs and TnAtcArs were sufficiently different for them not to have been transferred from one type of bacterium to the other in the biooxidation tank. The second set of arsenic resistance genes conferred very low levels of resistance in E. coli and appeared to be poorly expressed in both L. ferriphilum and E. coli.     

Field trial evaluating the influence of prophylactic and therapeutic antimicrobial administration on antimicrobial resistance of fecal Escherichia coli in dairy calves

The objective of this study was to describe the influence of in-feed and therapeutic antimicrobials on resistance in commensal fecal Escherichia coli isolated from preweaned calves. Four groups of 30, day-old calf-ranch calves were enrolled and raised until 4 weeks of age. Groups 1 to 3 were raised without antimicrobials in the feed. Group 1 was isolated from the other groups and received no antimicrobial therapy. Group 2 was housed on the calf ranch and did not receive antimicrobial therapy, whereas groups 3 and 4 could be treated with antimicrobials. Group 4 was fed neomycin and tetracycline HCl in the milk replacer. Fecal samples were collected from calves on days 1, 14, and 28. Three E. coli isolates per sample were evaluated for susceptibility to 12 antimicrobials. Cluster analysis was used to group isolates having similar susceptibility patterns. Cumulative logistic regression was used to evaluate factors associated with increasing levels of multiple antimicrobial resistance. In-feed antimicrobials were associated with higher levels of multiple antimicrobial resistance in fecal E. coli.f In calves not receiving in-feed antimicrobials, older calves had higher levels of resistance compared to day-old calves. Individual antimicrobial therapy increased resistance in these calves but appeared to be transient. There was no environmental influence on resistance in E. coli populations among study groups.     

Quantifying antimicrobial resistance at veal calf farms

This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm) were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.5 mg/L cefotaxime, 0.125 mg/L ciprofloxacin and 8/152 mg/L trimethoprim/sulfamethoxazole (tmp/s) by replica plating. From each faecal sample another 10 selected E. coli isolates were tested for their resistance by broth microdilution as a reference. Logistic regression analysis was performed to compare the odds of testing an isolate resistant between both test methods (replica plating vs. broth microdilution) and to evaluate the effect of pooling faecal samples. Bootstrap analysis was used to investigate the precision of the estimated prevalence of resistance to each antimicrobial obtained by several simulated sampling strategies. Replica plating showed similar odds of E. coli isolates tested resistant compared to broth microdilution, except for ciprofloxacin (OR 0.29, p≤0.05). Pooled samples showed in general lower odds of an isolate being resistant compared to individual samples, although these differences were not significant. Bootstrap analysis showed that within each antimicrobial the various compositions of a pooled sample provided consistent estimates for the mean proportion of resistant isolates. Sampling strategies should be based on the variation in resistance among isolates within faecal samples and between faecal samples, which may vary by antimicrobial. In our study, the optimal sampling strategy from the perspective of precision of the estimated levels of resistance and practicality consists of a pooled faecal sample from 20 individual animals, of which 90 isolates are tested for their susceptibility by replica plating.     

Diarrheagenic Escherichia coli in acute gastroenteritis in infants in North-West Italy

Enteropathogenic Escherichia coli may cause diarrhoea in infancy, but it is not routinely detected and regarded as a major causative agent. The aim of the present study was to estimate the incidence of enteropathogenic E. coli infection and to investigate its epidemiology and pathogenesis from faecal specimens in infants hospitalized for acute gastroenteritis. Between March 2008 and June 2009, faecal samples were collected and examined to recognize diarrhoeal aetiology, especially for E. coli, by cultural identification and multiplex-PCR. E. coli were isolated in 75 of 160 collected samples (46,88%); 10 samples of which (6,3%) had been positively recognised for pathogenic genes. Data showed that the presence of diarrheagenic E. coli infection was 6.3%, but it becomes 5% considering E. coli as a unique agent responsible for diarrhoea. The datum is not statistically meaningful because of the small sample (p>0,05). Bacterial pathogens were also isolated in 60 samples (37,5% of the total collected samples): 15 Salmonella spp., 8 Klebsiella pneumoniae, 9 Klebsiella oxytoca, 11 Citrobacter freundii, 5 Pseudomonas aeruginosa, 2 Serratia spp., 7 Enterobacter cloacae, 1 Shigella spp., 2 Campylobacter spp. Rotavirus was the predominant pathogenic single etiologic agent identified. It was found in 35 samples (21.88% of the overall collected samples), while Adenovirus, serotypes 40 or 41, was isolated in 2 samples (1.3%). Rotavirus infection was found predominantly in winter with respect to autumn. Data provide an interesting epidemiologic survey of enteropathogenic E. coli, which is not usually detected, although it may have potential clinical implications. Abbreviations: CDEC, detaching E. coli; DAEC, diffusely adherent E. coli; EAggEC, enteroaggregative E. coli; EHEC, enterohaemorrhagic E. coli; EIEC, enteroinvasive E. coli; EPEC, enteropathogenic E. coli; ETEC, enterotoxigenic E. coli.     

Bacteriological studies on Iraqi milk products

F. ABBAR AND H. KH. KADDAR. 1991. Samples from different types of domestic milk products including cheese, kishfa and gaymer were assessed for bacteriological quality over a 4-month period. A total of 400 samples were randomly selected across Mosul city and tested for faecal coliform counts, enteropathogenic Escherichia coli (EPEC) and enterotoxigenic E. coli (ETEC). Faecal coliforms were present at levels greater than 10² cfu/g in 72.5% and less than 10² cfu/g in 27.5% of samples. Of the 430 E. coli strains isolated from the 400 samples of milk products, 138 were serotypes of EPEC. These were found in 81 (40.5%) samples of cheese, 35 (23.8%) of kishfa and 22 (29.7%) of gaymer. During this period, 26 strains of ETEC were also isolated, all of which demonstrated heat-labile or heat-stable toxins. The high proportion of strains of three groups of E. coli showing resistance to antibiotics is discussed in relation to widespread use of antibiotics and the possible public health implication.     

Detection of carbohydrases as a possible method of differentiating faecal and non-faecal Escherichia coli

Abstract Escherichia coli isolated from faeces, urine, wounds and pus were examined for the production of carbohydrases, i.e., maltase, lactase and invertase. Two of the carbohydrases, lactase and maltase, have been detected in E. coli of faecal origin (100 strains) whereas these enzymes were not detected in non-faecal E. coli (146 strains). These inductive enzymes were produced optimally in synthetic medium, pH 7.2, at 37°C for 10 h.
The presence of maltase and lactase in the faecal E. coli may be used as a complementary test for differentiating faecal E. coli from non-faecal E. coli .     

Studies on Coli-aerogenes and Other Gram-negative Intestinal Bacteria in Various Animals and Birds

S ummary . Some faecal material from native animals and birds (especially) showed either no coli-aerogenes bacteria or contained types other than Escherichia coli I.
Amongst coli-aerogenes isolates, E. coli I was frequent but the high percentage of other biotypes indicated that the animal host may serve as a pool of intermediate and irregular strains. Paracolons and Proteus spp. were abundant, and Salmonella spp. were isolated from dogs and native animals possibly in contact with man.
Animals were only occasionally carriers of enteropathogenic E. coli serotypes and seldom of types locally important in the etiology of infantile diarrhoea, such as E. coli O26:B6 and O55:B5. In this series O86 serotypes other than the diarrhoeal strain isolated from babies were found. The results of the study indicated some degree of host specificity. In the group of 20 O serotypes (referred to as specific E. coli ), O8 was most commonly listed. Most strains were sensitive to chemotherapeutic agents but resistance of some strains especially to sulphonamide was recorded.
The implication of the presence in the animal gut of coli-aerogenes bacteria other than E. coli type I is discussed in relation to bacterial standards for drinking water.     

An adapted ImmunoMagnetic cell separation method for use in quantification of Escherichia coli O157:H7 from bovine faeces

Detection of Escherichia coli O157:H7 organisms in food, clinical or environmental samples is necessary for diagnosis of infection and epidemiological investigations. However, this pathogen may be present in low numbers and difficult to identify among high numbers of other background bacteria. In order to increase the sensitivity of culture- and PCR detection, pre-enrichment of E. coli O157:H7 in broth culture combined with ImmunoMagnetic cell Separation (IMS) is routinely employed. These methods, although able to detect levels as low as 2 cfu/g (from 10 to 25 g samples), are qualitative detection strategies only. If the actual numbers of E. coli O157:H7 are to be quantified, growth enrichment must be excluded and the organisms isolated directly from the sample of interest. Such quantification is necessary, for example, to determinate contamination levels on beef carcasses and for determination of bacterial numbers in in vivo gene expression studies. In the present study, it was not possible to recover organisms from bovine faecal suspensions using the customary IMS system and so a range of alternative buffers and other paramagnetic beads was tested. Combination of a 6.2-microm diameter bead with a detergent-based buffer gave optimal recovery of E. coli O157:H7 organisms from faecal suspensions. This system was validated for recovery of E. coli O157:H7 by comparing it with that obtained with the standard Dynabeads IMS protocol, using both the traditional broth enrichment method and a quantitative detection approach. We conclude that a 6.2-microm diameter Aureon bead can be used for quantitative isolation of E. coli O157:H7 directly from bovine faeces and, for this purpose, is preferred to the 2.8-microm diameter Dynal bead.     

Fluctuations in the occurrence of Escherichia coli O157:H7 on a Norwegian farm*

AIM: To describe the distribution of Escherichia coli O157:H7 on a sporadically positive dairy farm and on possible contact farms over a one-year period. METHODS AND RESULTS: Environmental and faecal samples from all animals at the farm, and faecal samples from animals at contact farms were analysed for E. coli O157:H7 by immunomagnetic separation methods or VIDAS.Confirmed isolates were tested for cytotoxicity in the Vero cell assay and typed by PFGE. Escherichia coli O157:H7 (stx2 and eae) of the same PFGE type were isolated from cattle, sheep, hens and environmental samples at variable levels during summer and fall 2002, but were not detected in 2003. CONCLUSIONS: Escherichia coli O157:H7 had a widespread distribution on the farm investigated, but the original source of contamination could not be identified. The occurrence of this bacterium on the farm did not result in any detectable increase in gastrointestinal disease in the associated population. SIGNIFICANCE AND IMPACT OF THE STUDY: Despite a low endemic level of E. coli O157:H7 in the Norwegian cattle population, the growth and spread of this potentially important bacterium may occur.     

Evaluation of antibiotic resistance analysis and ribotyping for identification of faecal pollution sources in an urban watershed

AIMS: The accuracy of ribotyping and antibiotic resistance analysis (ARA) for prediction of sources of faecal bacterial pollution in an urban southern California watershed was determined using blinded proficiency samples. METHODS AND RESULTS: Antibiotic resistance patterns and HindIII ribotypes of Escherichia coli (n = 997), and antibiotic resistance patterns of Enterococcus spp. (n = 3657) were used to construct libraries from sewage samples and from faeces of seagulls, dogs, cats, horses and humans within the watershed. The three libraries were analysed to determine the accuracy of host source prediction. The internal accuracy of the libraries (average rate of correct classification, ARCC) with six source categories was 44% for E. coli ARA, 69% for E. coli ribotyping and 48% for Enterococcus ARA. Each library's predictive ability towards isolates that were not part of the library was determined using a blinded proficiency panel of 97 E. coli and 99 Enterococcus isolates. Twenty-eight per cent (by ARA) and 27% (by ribotyping) of the E. coli proficiency isolates were assigned to the correct source category. Sixteen per cent were assigned to the same source category by both methods, and 6% were assigned to the correct category. Addition of 2480 E. coli isolates to the ARA library did not improve the ARCC or proficiency accuracy. In contrast, 45% of Enterococcus proficiency isolates were correctly identified by ARA. CONCLUSIONS: None of the methods performed well enough on the proficiency panel to be judged ready for application to environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Most microbial source tracking (MST) studies published have demonstrated library accuracy solely by the internal ARCC measurement. Low rates of correct classification for E. coli proficiency isolates compared with the ARCCs of the libraries indicate that testing of bacteria from samples that are not represented in the library, such as blinded proficiency samples, is necessary to accurately measure predictive ability. The library-based MST methods used in this study may not be suited for determination of the source(s) of faecal pollution in large, urban watersheds.     

Effects of chronic triclosan exposure upon the antimicrobial susceptibility of 40 ex-situ environmental and human isolates

BACKGROUND: Triclosan (TCS) exposure of Escherichia coli selects for tolerant clones, mutated in their enoyl-acyl carrier protein reductase (FabI). It has been inferred that this phenomenon is widespread amongst bacterial genera and might be associated with resistance to third party agents. METHODS: Ex-situ, low passage isolates of enteric, human axilla, human oral origin and bacteria isolated from a domestic drain, together with selected type cultures were exposed to escalating concentrations of TCS over 10 passages using a gradient plate technique. One fresh faecal isolate of E. coli was included as a positive control. TCS susceptibility was determined for all strains before and after exposure, whilst enteric isolates were additionally assessed for susceptibility towards chlorhexidine, tetracycline, chloramphenicol, nalidixic acid and ciprofloxacin, and the oral isolates towards chlorhexidine, tetracycline and metronidazole. RESULTS: Triclosan exposure of E. coli markedly decreased TCS susceptibility. TCS susceptibility also decreased for Klebsiella oxytoca, Aranicola proteolyticus and Stenotrophomonas maltophilia. Susceptibility of the remaining 35 strains to TCS and the other test agents remained unchanged. CONCLUSIONS: These data suggest that selection for high level resistance by TCS exposure is not widespread and appears to be confined to certain enteric bacteria, especially E. coli. Change in TCS susceptibility did not affect susceptibility towards chemically unrelated antimicrobials. SIGNIFICANCE AND IMPACT: Acquired high-level TCS resistance is not a widespread phenomenon.     

Heterogeneous distributions of Escherichia coli O157 within naturally infected bovine faecal pats

Escherichia coli O157 is an important human pathogen for which cattle are considered a reservoir. This paper describes and models the variation in counts of E. coli O157 that exists within individual bovine faecal pats. The presence and concentration of E. coli O157 in faecal samples was determined using a combination of direct spiral plating followed by a more sensitive isolation procedure. The data were modelled using multilevel random effect models, in which the random effects were allowed to be correlated to allow for the fact that pooled and individual samples come from the same pat. Up to a two log difference in the concentration of E. coli O157 was demonstrated in samples from different areas within a faecal pat. Pooling of individual samples from throughout the faecal pat and processing it as one composite sample allows this heterogeneity to be overcome.     

The use of lauryl tryptose broth containing 4-methylumbelliferyl-β-D-glucuronide (MUG) to enumerate Escherichia coli from freshwater sediment

Most-Probable-Number tests for Escherichia coli were performed on 45 sediment samples using Lauryl Tryptose broth (LTB) containing 4-methylumbelliferyl-β-D-glucuronide (MUG). Eighty-three percent of 493 LTB-MUG reactions agreed with results obtained by conventional faecal coliform analysis. Although false-negative reactions are suspected in about 9% of the LTB-MUG tubes, anaerogenic E. coli , that would not be enumerated by conventional faecal coliform tests were recovered using LTB-MUG. The high percentage of agreement between the two methods suggests that the MPN method employing LTB-MUG is adequate to enumerate E. coli from some freshwater sediments.     

Evaluation of a PCR detection method for Escherichia coli O157:H7/H- bovine faecal samples

AIMS: Combinations of PCR primer sets were evaluated to establish a multiplex PCR method to specifically detect Escherichia coli O157:H7 genes in bovine faecal samples. METHODS AND RESULTS: A multiplex PCR method combining three primer sets for the E. coli O157:H7 genes rfbE, uidA and E. coli H7 fliC was developed and tested for sensitivity and specificity with pure cultures of 27 E. coli serotype O157 strains, 88 non-O157 E. coli strains, predominantly bovine in origin and five bacterial strains other than E. coli. The PCR method was very specific in the detection of E. coli O157:H7 and O157:H- strains, and the detection limit in seeded bovine faecal samples was <10 CFU g(-1) faeces, following an 18-h enrichment at 37 degrees C, and could be performed using crude DNA extracts as template. CONCLUSIONS: A new multiplex PCR method was developed to detect E. coli O157:H7 and O157:H-, and was shown to be highly specific and sensitive for these strains both in pure culture and in crude DNA extracts prepared from inoculated bovine faecal samples. SIGNIFICANCE AND IMPACT OF THE STUDY: This new multiplex PCR method is suitable for the rapid detection of E. coli O157:H7 and O157:H- genes in ruminant faecal samples.     

Occurrence, virulence characteristics and antimicrobial resistance of Escherichia coli O157 in slaughtered cattle and diarrhoeic calves in West Bengal, India

AIMS: (i) To study the occurrence of Escherichia coli serotype O157 in cattle stool in West Bengal, India, and (ii) the virulence properties and antimicrobial resistance of the E. coli isolates. METHODS AND RESULTS: Following enrichment in modified EC broth and plating onto HiCrome MS.O157 agar, a total of 14 strains of E. coli serotype O157 was isolated from faecal samples from two (2.04%) slaughtered cattle and six (7.59%) diarrhoeic calves. By multiplex PCR, Shiga toxin genes were detected in all the isolates. The enterohaemolysin phenotype was found in all, but one strain. Among 14 strains, ten were resistant to at least one of the antimicrobial agents tested. Multiple antibiotic resistance was frequent. CONCLUSIONS: The study showed that occurrence of Shiga toxin-producing and multiple antibiotic-resistant E. coli O157 among cattle population in this region of India is significant. SIGNIFICANCE AND IMPACT OF THE STUDY: Considering routine human contacts with cattle, a large human population in this region may be at risk for exposure to Shiga toxin-producing E. coli O157.