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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #236542

Title: Clostridium difficile in mixed populations of animals and humans

item Harvey, Roger
item Hume, Michael
item Andrews, Kathleen - Kate
item McReynolds, Jackson

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/25/2009
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Objectives: Since 2003, there has been an emergence of BI/NAP1 strain of Clostridium difficile (Cd) in North American hospitals. The origins of this epidemic strain have yet to be determined. However, PFGE analysis has shown ~80% similarity between this strain and some swine isolates. The objectives of this study were to determine the prevalence of Cd in mixed populations of swine and humans and to compare our isolates to other animal and human isolates. Methods: Cultivation of Cd was accomplished by an alcohol shock, enrichment/centrifugation concentration, and use of restrictive media. Isolates were characterized by PCR for presence of tcdA, tcdB, tcdC, and cdtB toxin genes. Sensitivities to eleven antibiotics were determined. Results: Of 1008 swine fecal samples tested, 131 (13%) were positive for Cd. Nursing piglets had a prevalence of 36.5% compared to less than 10% for older age groups. Most isolates (127/131) were positive for toxins A, B, and binary toxin, and had the tcdC gene deletion. There was an increased prevalence of Cd in swine during colder months compared to warmer months. Prevalence of Cd from human wastewater was 100/818 (12.2%). No differences in human isolation rates were noted on the basis of seasonality or for occupation (swine worker versus non-swine worker). Our swine and human isolates generally had similar antibiotic resistance patterns to 11 antibiotics. Conclusions: Although piglets had a high prevalence of Cd, we believe that reduced carriage (3.9%) in grower/finisher swine may be a factor for decreased transmission risk for Cd in the food chain. Occupational exposure to pigs that were positive for Cd did not appear to affect human colonization. Our Cd isolates appeared to have decreased antibiotic resistance compared to that reported for human clinical isolates.