Multilocus sequence typing performed on Campylobacter coli isolates from humans, broilers, pigs and cattle originating in Denmark

Aim: To assess whether Campylobacter coli isolated from different sources in Denmark constitute separate populations. Methods and Results: Multilocus sequence typing (MLST) was applied to 160 C. coli isolates from animal origin, food products and human cases of gastroenteritis. The isolates were collected in Denmark over a 2-year period. In total, 84 sequence types (STs) were obtained and 57 of these STs were novel to this study. Ten per cent of the isolates possessed STs that were found in both human, poultry and pig isolates. Only 10% of the isolates from pigs shared ST with isolates from humans, and these shared STs were found in poultry isolates as well. Conclusions: Great genetic diversity was seen within the Danish C. coli population. Furthermore, we found that the C. coli types isolated from Danish pigs constitute a small fraction of the C. coli causing human disease. Significance and Impact of the Study: C. coli isolates from pigs is presumably not a significant source of human campylobacteriosis in Denmark. The Danish C. coli isolates include 68% STs novel to this study, showing a great diversity compared with studies from other countries.