Detection and Enumeration ofClostridium difficileSpores in Retail Beef and Pork

Abstract

Recent studies have identified Clostridium difficile in food animals and retail meat, and concern has been raised about the potential for food to act as a source of C. difficile infection in humans. Previous studies of retail meat have relied on enrichment culture alone, thereby preventing any assessment of the level of contamination in meat. This study evaluated the prevalence of C. difficile contamination of retail ground beef and ground pork in Canada. Ground beef and ground pork were purchased from retail outlets in four Canadian provinces. Quantitative and enrichment culture was performed. Clostridium difficile was isolated from 28/230 (12%) samples overall: 14/115 (12%) ground beef samples and 14/115 (12%) ground pork samples (P ‫؍‬ 1.0). For ground beef, 10/14 samples (71%) were positive by enrichment culture only. Of the 4 ground beef samples that were positive by direct culture, 20 spores/g were present in 2 while 120 and 240 spores/g were present in 1 each. For ground pork, 10/14 (71%) samples were positive by enrichment culture only. Of the 4 ground pork samples that were positive by direct culture, 20 spores/g were present in 3 while 60 spores/g were present in 1. Ribotype 078 predominated, consistent with some previous studies of C. difficile in food animals. Ribotype 027/North American pulsotype 1 was also identified in both retail beef and pork. This study has identified relatively common contamination of retail ground beef and pork with C. difficile spores; however, the levels of contamination were very low.

Clostridium difficile infection: Early history, diagnosis and molecular strain typing methods

“…Rather, it seems that an increase in the time of enrichment is best for improving the sensitivity of the method. A bacterial competition in the enrichment broth has been observed [164]. In a previous study on carcasses and faecal samples [116], after 30 days of enrichment, different C. difficile types were identified, and colonies other than C. difficile were rarely present in the plate.…”

Clostridium difficileinfection

“…110 In the past two years, multiple reports have raised the possibility of zoonotic transmission of C. difficile, particularly from retail foods. 113 The prevalence of C. difficile, including epidemic strains, has been documented in cooked and un-cooked meats, 109,[114][115][116] as well as in produce. 117,118 Molecular typing of organisms isolated from food has revealed, in multiple cases, identical genotypes to C. difficile strains recovered from human CDI patients as well as food animals.…”

Clostridium difficile infection: management strategies for a difficult disease

“…C. difficile strains that cause human disease have been identified in retail meat and meat products including beef, chicken and pork [Jhung et al 2008;Weese et al 2010]. Person-to-person spread is important both in hospitals and outside the hospitals.…”