Results of a longitudinal study of the prevalence of Escherichia coli O157:H7 on cow-calf farms

Sargeant, Jan M.; Gillespie, J. R.; Oberst, Richard D.; Phebus, Randall K.; Hyatt, Doreene R.; Bohra, Lalit Kumar; Galland, John C.

doi:10.2460/ajvr.2000.61.1375

Cited by 76 publications

(63 citation statements)

References 27 publications

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“…Outside Thailand the LTIIa toxin gene has not been reported in hosts other than cattle (33 In this study the simultaneous prevalence of the three traits associated with the O157 genotype is 1:182 E. coli (0.55% of E. coli), similar to reports in the literature (38,47). Our study examined occurrence among total E. coli while most examined occurrence in fecal samples.…”

Section: Discussionsupporting

confidence: 75%

“…Our study examined occurrence among total E. coli while most examined occurrence in fecal samples. The rate of infection in cows is estimated to be 1 to 2 percent (38) and is hence difficult to detect on a farm through single-isolate screening of fecal samples. Our data suggest that screening large numbers of isolates provides an easy approach for detecting this genotype in farm waste ponds.…”

Section: Discussionmentioning

confidence: 99%

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Occurrence of Genes Associated with Enterotoxigenic and Enterohemorrhagic Escherichia coli in Agricultural Waste Lagoons

Chern

Tsai

Olson

2004

Appl Environ Microbiol

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The prevalence among all Escherichia coli bacteria of the LTIIa toxin gene and STII toxin gene, both associated with enterotoxigenic E. coli, and of three genes (stxI, stxII, and eaeA) associated with enterohemorrhagic E. coli was determined in farm waste disposal systems seasonally for 1 year. Single-and nested-PCR results for the number of E. coli isolates carrying each toxin gene trait were compared with a five-replicate most-probable-number (MPN) method. The STII and LTIIa toxin genes were present continuously at all farms and downstream waters that were tested. Nested-MPN-PCR manifested sensitivity increased over that of single-MPN-PCR by a factor of 32 for LTIIa, 10 for STII, and 2 for the stxI, stxII, and eaeA genes. The geometric mean prevalence of each toxin gene within the E. coli community in waste disposal site waters after nested MPN-PCR was 1:8.5 E. coli isolates (1:8.5 E. coli) for the LTIIa toxin gene and 1:4 E. coli for the STII toxin gene. The geometric mean prevalence for the simultaneous occurrence of toxin genes stxI, stxII, and eaeA, was 1:182 E. coli. These findings based on total population analysis suggest that prevalence rates for these genes are higher than previously reported in studies based on surveys of single isolates. With a population-based approach, the frequency of each toxin gene at the corresponding disposal sites and the endemic nature of diseases on farms can be easily assessed, allowing farmers and public health officials to evaluate the risk of infection to animals or humans.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Occurrence of Genes Associated with Enterotoxigenic and Enterohemorrhagic Escherichia coli in Agricultural Waste Lagoons

Chern

Tsai

Olson

2004

Appl Environ Microbiol

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“…Fecal shedding of O157 in cattle is reported to be highly intermittent, with variable number of animals in a given herd shedding detectable levels of O157 for several weeks (21,45). These reports support our findings that the fecal shedding profile of O157 in calves inoculated with the wild-type or hha mutant strain continued to show a negative trend for 2 weeks before establishing a low-level intermittent shedding response over the course of the following 2 weeks.…”

Section: Discussionsupporting

confidence: 81%

Correlating Levels of Type III Secretion and Secreted Proteins with Fecal Shedding of Escherichia coli O157:H7 in Cattle

et al. 2012

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The locus of enterocyte effacement (LEE) of Escherichia coli O157:H7 (O157) encodes a type III secretion system (T3SS) for secreting LEE-encoded and non-LEE-encoded virulence proteins that promote the adherence of O157 to intestinal epithelial cells and the persistence of this food-borne human pathogen in bovine intestines. In this study, we compared hha sepB and hha mutants of O157 for LEE transcription, T3SS activity, adherence to HEp-2 cells, persistence in bovine intestines, and the ability to induce changes in the expression of proinflammatory cytokines. LEE transcription was upregulated in the hha sepB and hha mutant strains compared to that in the wild-type strain, but the secretion of virulence proteins in the hha sepB mutant was severely compromised. This reduced secretion resulted in reduced adherence of the hha sepB mutant to Hep-2 cells, correlating with a significantly shorter duration and lower magnitude of fecal shedding in feces of weaned (n ‫؍‬ 4 per group) calves inoculated with this mutant strain. The levels of LEE transcription, T3SS activity, and adherence to HEp-2 cells were much lower in the wild-type strain than in the hha mutant, but no significant differences were observed in the duration or the magnitude of fecal shedding in calves inoculated with these strains. Examination of the rectoanal junction (RAJ) tissues from three groups of calves showed no adherent O157 bacteria and similar proinflammatory cytokine gene expression, irrespective of the inoculated strain, with the exception that interleukin-1␤ was upregulated in calves inoculated with the hha sepB mutant. These results indicate that the T3SS is essential for intestinal colonization and prolonged shedding, but increased secretion of virulence proteins did not enhance the duration and magnitude of fecal shedding of O157 in cattle or have any significant impact on the cytokine gene expression in RAJ tissue compared with that in small intestinal tissue from the same calves. Enterohemorrhagic Escherichia coli (EHEC) O157:H7 (referred to here as O157) causes a broad spectrum of diarrheal illnesses, including uncomplicated diarrhea, hemorrhagic colitis (HC), and hemolytic-uremic syndrome (HUS) (34). O157 infections are the major cause of acute renal failure in young children in the United States (34). Shiga toxins encoded by the stx 1 and stx 2 genes (52) are the major virulence factors responsible for the development of HC and HUS. Among ruminants, cattle are considered the major reservoir for O157 and animals colonized with these bacteria serve as major direct and indirect sources of this pathogen (28). O157 colonizes the large intestines of cattle, especially the cecum and tissues of the rectoanal junction (RAJ) (7, 37). Colonization requires intimate adherence of O157 bacteria to intestinal epithelial cells, a process that culminates in the formation of characteristic histopathological lesions called attaching and effacing (A/E) lesions. A/E histopathology results from the rearrangements of cytoskeletal elements of mucosal epithe...

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“…The prevalence of EHEC O157 in cattle has been reported to be 0.2-60.4% in the United States [10,13,23,28], 1.9% in Australia [7], and 4.2-66.7% in Europe [5,6,16,24]. In Japan, it was reported that the isolation rate of the EHEC was between 0.3% [12] and 6.5% [15] in faeces samples from animals delivered to a slaughterhouse.…”

Section: Shiga Toxin (Stx)-producing Escherichia Coli (Stec) Ismentioning

confidence: 99%

A Three-Year Study of Enterohemorrhagic Escherichia coli O157 on a Farm in Japan

Ezawa

Gocho

Saitoh

et al. 2004

The Journal of Veterinary Medical Science

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ABSTRACT. A long-term study was performed on the prevalence of enterohemorrhagic Escherichia coli (EHEC) O157 in bovine faeces. The present study was conducted on heifers raised on a farm showing a high isolation rate of EHEC O157 in previous years. The p revalence of EHEC O157 isolated from faecal samples was 10.6% (222/2104), 5.6% (181/3225), and 5.6% (153/2744) from 1998 to 2000, respectively. The numbers of EHEC O157-positive heifers for the same 3 years were 46.3% (185/400), 36.8% (147/399), and 31.7% (130/410), respectively. The seasonal prevalence of EHEC O157 varied according to the year. Most positive heifers excreted the EHEC O157 only once during the survey, though it was excreted 2 or 3 times by some heifers. The results obtained in the present study showed that the farm examined was heavily contaminated with EHEC O157. It is assumed that EHEC O157 does not remain in individual catt le long-term, but does exist long-term on farms due to repeated infection.

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Results of a longitudinal study of the prevalence of Escherichia coli O157:H7 on cow-calf farms

Cited by 76 publications

References 27 publications

Occurrence of Genes Associated with Enterotoxigenic and Enterohemorrhagic Escherichia coli in Agricultural Waste Lagoons

Occurrence of Genes Associated with Enterotoxigenic and Enterohemorrhagic Escherichia coli in Agricultural Waste Lagoons

Correlating Levels of Type III Secretion and Secreted Proteins with Fecal Shedding of Escherichia coli O157:H7 in Cattle

A Three-Year Study of Enterohemorrhagic Escherichia coli O157 on a Farm in Japan

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