Diversity of Campylobacter coli genotypes in the lower porcine gastrointestinal tract at time of slaughter

Aims: To compare the genotypes of Campylobacter coli obtained from the rectal and ileal samples of pigs at the time of slaughter. Methods and Results: Five animals were sampled following slaughter with ileal contents and anal swabs being taken post-evisceration. Swabs were directly plated onto charcoal cefoperazone desoxycholate agar (CCDA) while ileal contents were enriched in CCDA broth. Twenty isolates were picked from each site sampled and all 200 isolates were Camp. coli. Isolates were genotyped using random amplified polymorphic DNA (22 discrete types) and flaA (11 discrete types). Both methods found that 55% of the genotypes were unique to rectal samples. Only one animal yielded the same flaA type from ileal and rectal samples. Conclusions: Rectal sampling of pigs yielded a more diverse subset of Camp. coli genotypes than ileal contents, but failed to yield all of the genotypes carried by an individual animal. Significance and Impact of the Study: A small sample of pigs carried a very diverse population of Camp. coli genotypes; and sampling of a single site in the gut will recover only part of this population. Hence, any genotyping studies of Camp. coli in pigs must be interpreted with caution, and epidemiological studies could be confounded by the number of Camp. coli genotypes available.