<em>Clostridium difficile</em> and Methicillin-Resistant <em>Staphylococcus aureus</em> Shedding by Slaughter-Age Pigs

The prevalence of C. difficile and MRSA in slaughter-age pigs sampled in Canada was relatively low at 3.4 per cent and 0.2 per cent, respectively, but researchers said that there is potential for contamination of meat from healthy pigs carrying this pathogen into slaughterhouses.

21 August 2011

3 minute read

Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA) are critical human pathogens and of increasing concern in food animals, according to J. Scott Weese of the University of Guelph and co-authors there and at other organisations in Guelph and Saskatoon in Canada. Because of the apparent impact of age on prevalence of these organisms, studies of slaughter-age pigs are important when considering the potential for contamination of food. This study evaluated C. difficile and MRSA shedding by slaughter-age pigs from farms across Canada.

C. difficile was isolated from 30/436 (6.9 per cent) samples from 15/45 (33 per cent) of farms. After adjusting for clustering at the herd level, the prevalence was 3.4 per cent. Ribotype 078 (toxinotype V, North American Pulsotype 7) was the most common strain, accounting for 67 per cent of isolates. MRSA was isolated from 21/460 (4.6 per cent) pigs from 5/46 (11 per cent) farms. The prevalence in pigs after adjusting for clustering at the herd level was 0.2 per cent. Seven different spa types were identified, with three related spa types (t011, t034, new) accounting for 16 (76 per cent) consistent with ST398 predominating.

Both MRSA and C. difficile samples were collected from 45 farms. Both MRSA and C. difficile were detected on 2 (4.4 per cent), with C. difficile only on 13 (29 per cent), MRSA only on 3 (6.7 per cent) and neither on 27 (60 per cent).

The prevalence of C. difficile and MRSA in slaughter age pigs was relatively low, particularly in comparison with studies involving younger pigs, concluded Weese and his co-authors. The predominance of C. difficile ribotype 078 and MRSA ST398 was not surprising, but there was diversity in strain types and the majority of isolates of both organisms were strains that can be found in humans. While the prevalence of C. difficile and MRSA in slaughter age pigs was relatively low, there is clearly potential for contamination of meat from healthy pigs carrying this pathogen into slaughterhouses.

Reference

Weese J.S., J. Rousseau, A. Deckert, S. Gow and R.J. Reid-Smith. 2011. Clostridium difficile and methicillin-resistant Staphylococcus aureus shedding by slaughter-age pigs. BMC Veterinary Research, 7:41 doi:10.1186/1746-6148-7-41