Prevalence of Clostridium difficile in Korean Ground Meat Products

Introduction: Clostridium difficile is a spore-forming, rod-shaped bacterium and is one of the most frequent causes of severe antibiotic-associated diarrhea (AAD), leading to pseudomembranous colitis, which is a severe inflammation of the colon. C. difficile is one of the most common nosocomial pathogens. Ground meat products have been reported as the vehicle of C. difficile, and many countries have reported widely varying results on the prevalence of contamination.

Purpose: We monitored the prevalence of C. difficile contamination in ground meat products purchased in Korea, Seoul.

Methods: The purchased sample was aseptically weighed and 5 g of the sample was inoculated in 20 ml brain heart infusion (BHI) broth, and incubated anaerobically at 37°C for 10-15 days. From the enriched culture, 1 ml was added to 1 ml of 95% ethanol and allowed to stand for 30 min. After centrifugation (3800 x g, 10 min), the sediment was streaked onto Clostridium difficile selective agar (CDSA) plates and incubated at 37°C for 2 days. After incubation, the plates were examined under long-wave ultraviolet light for the green/yellow fluorescence of C. difficile colonies. The presumptive C. difficile colonies were tested for indole production, L-proline-aminopeptidase activity using the PRO Kit, and checked for the presence of tpi, tcdA, tcdB genes by using PCR.

Results: C. difficile was isolated from 1 ground beef of 400 retail ground meat purchased over a 15-month period from 2011 to 2012 in Korea. The isolated strain had a toxin A gene but not the toxin B gene.

Significance: Prevalence of C. difficile in meat, including pork and beef, has been widely reported to range from 0% to 42%, worldwide. Our study showed that 0.25% of Korean ground meat products were likely contaminated with C. difficile.