High prevalence of the epidemic Clostridium difficile PCR ribotype 078 in Iberian free-range pigs

Previous studies in intensively raised piglets have detected a high prevalence of the epidemic Clostridium difficile PCR ribotype 078. In this article we present a longitudinal survey of C. difficile colonisation in a population of Iberian pigs reared under a free-range system. A total of 160 faecal samples from 20 piglets belonging to different litters were obtained by weekly sampling. C difficile was recovered from samples collected at different times throughout the survey from a 90% of piglets, resulting in an overall prevalence of 25.6% in the studied samples. Most positive samples (75.6%) came from <= 15-day animals, but some piglets shed C. difficile even on day +50. All isolates were ribotype 078, harboured toxin-encoding genes and showed in vitro resistance to several fluoroquinolones. A majority of isolates (80.5%) were also high-level resistant to ertapenem, and four metronidazole heteroresistant isolates (9.8%) were detected. In conclusion, Iberian free-range pigs can be a potential reservoir of epidemic antimicrobial-resistant strains of C. difficile, showing a prevalence rate similar to that found for intensively raised animals. (c) 2013 Elsevier Ltd. All rights reserved.