Distribution of Escherichia coli O157 in bovine fecal pats and its impact on estimates of the prevalence of fecal shedding

• Published in: Applied and Environmental Microbiology Vol. 70; no. 10; pp. 5737 - 5743
• Main Authors: Pearce, M.C, Fenlon, D, Low, J.C, Smith, A.W, Knight, H.I, Evans, J, Foster, G, Synge, B.A, Gunn, G.J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.10.2004
• Subjects: Animal Husbandry; Animals; Bacteria; Bacteriology; Biological and medical sciences; Cattle; Cattle - microbiology; Colony Count, Microbial - methods; Colony Count, Microbial - statistics & numerical data; Cross-Sectional Studies; Escherichia coli; Escherichia coli O157 - isolation & purification; Estimates; fecal shedding; Feces; Feces - microbiology; Fundamental and applied biological sciences. Psychology; immunomagnetic separation; Immunomagnetic Separation - statistics & numerical data; isolation; Microbiology; Monte Carlo Method; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; population density; Public Health Microbiology; sampling; Scotland; Sensitivity and Specificity; spatial distribution; Scotland; Vertebrata; Mammalia; Prevalence; Bovine; Escherichia coli; Distribution; Pathogen strain; Bacteria; Artiodactyla; Feces; Ungulata; Enterobacteriaceae
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.70.10.5737-5743.2004

The distribution of Escherichia coli O157 in bovine feces was examined by testing multiple samples from fecal pats and determining the density of E. coli O157 in immunomagnetic separation (IMS)-positive fecal samples. The density of E. coli O157 in bovine feces was highly variable, differing by as much as 76,800 CFU g(-1) between samples from the same fecal pat. The density in most positive samples was <100 CFU g(-1), the limit of reliable detection by IMS. Testing only one 1-g sample of feces per pat with IMS may result in a sensitivity of detection as low as 20 to 50%. It is therefore probable that most surveys have greatly underestimated the prevalence of E. coli O157 shedding in cattle and the proportion of farms with shedding cattle. The sensitivity of the detection of E. coli O157 in bovine feces can be as much as doubled by testing two 1-g samples per pat rather than one 1-g sample.