Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/7/2008
Publication Date: 6/1/2008
Citation: Harvey, R.B., Norman, K.N., Scott, M.H., Hume, M.E., Andrews, K. 2008. Prevalence of Clostridium difficile in an integrated swine operation [abstract]. Proceedings of the 9th Biennial Congress of the Anaerobe Society of the Americas, June 23-27, 2008, Long Beach, CA. p. 151. Interpretive Summary:
Technical Abstract: The objective of this study was to compare the prevalence of Clostridium difficile among different age and production groups of swine in a vertically integrated swine operation in Texas in 2006 and to compare our isolates to other animal and human isolates. Isolation of C. difficile was performed utilizing an enrichment technique and restrictive media. Preliminary results are based on 131 C. difficile isolates arising from 1008 swine fecal samples and pork trim samples (overall prevalence of 13%). The prevalence (number positive/number tested in production type) of C. difficile was different between the groups (P less than 0.001), and was highest among farrowing barn inhabitants (predominantly piglets, but also included lactating sows and influent) at 36.5% (95/260), followed by 8.2% (10/122) for nursery, 6.5% (4/61) for pork products, 3.9% (15/382) for grower-finisher, and 3.8% (7/182) for breeding boars and sows. Isolates were tested for Toxins A and B using commercially available toxin test kits. Of the 131 isolates, 89/103 were positive for toxin A (28 not tested) and 127/131 were positive for toxins A and B. PCR was used to determine toxinotypes, ribotypes, and binary toxin. All 131 isolates harbored the tcdC gene deletion, typical of hyper-virulent toxin producing strains. Isolates were tested for sensitivity to 11 antibiotics. All 131 isolates were resistant to cefoxitin, ciprofloxacin, and imipenem, whereas all were sensitive to metronidazole, piperacillin/tazobactam, amoxicillin/clavulanic acid, and vancomycin. The majority of isolates were resistant to clindamycin; resistant or intermediate to ampicillin; and sensitive to tetracycline and chloramphenicol. There was an increased (P less than 0.001) number of isolates for the timeframe of Sept.-Feb. compared to Mar.-Aug. PCR and pulsed-field gel electrophoresis techniques will be used to make genomic comparisons of our isolates to those in the CDC database. In this study, we found C. difficile most commonly originated among farrowing barn production types (primarily piglets) and not in grower/finisher production. Relatively low prevalence in late production suggests a low food safety risk; however, the isolates of C. difficile in our study are considered more virulent because of the tcdC gene deletion, and similar isolates have been linked to outbreaks of C. difficile in hospitals of North America and Europe.