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Prevalence and genotypic characteristics of Clostridium difficle in a closed and integrated human and swine population

Norman, Keri N., Scott, H. Morgan, Harvey, Roger B., Norby, Bo, Hume, Michael E., Andrews, Kathleen
Applied and environmental microbiology 2011 v.77 no.16 pp. 5755
Clostridium difficile, risk, researchers, food safety, food retailing, bacterial colonization, farm labor, feces, food animals, foodborne infections, genotype, host strains, human population, humans, isolation techniques, livestock and meat industry, livestock production, meat production, occupational exposure, sewage effluent, swine
Recently, an apparent rise in the number of cases attributed to community-acquired Clostridium difficile infection has led researchers to explore additional sources of infection. The finding of C. difficile in food animals and retail meat has raised concern about potential food-borne and occupational exposures. The objective of this study was to compare C. difficile isolated from a closed population of healthy individuals consisting of both humans and swine in order to investigate possible food safety and occupational risks for exposure. Using a multistep enrichment isolation technique, we identified 11.8% of the human wastewater samples and 8.6% of the swine samples that were positive for C. difficile. The prevalences of C. difficile in swine production groups differed significantly (P < 0.05); however, the prevalences in the two human occupational group cohorts did not differ significantly (P = 0.81). The majority of the human and swine isolates were similar based on multiple typing methods. The similarity in C. difficile prevalence in the human group cohorts suggests a low occupational hazard, while a greatly decreased prevalence of C. difficile in later-stage swine production groups suggests a diminished risk for food-borne exposure. The similarity of strains in the two host species suggests the possibility of a common environmental source for healthy individuals in a community setting.