Genetic diversity and host associations in Campylobacter jejuni from human cases and broilers in 2000 and 2008

•We investigate the molecular epidemiology of domestic campylobacteriosis in Sweden.•Source attribution confirmed poultry C. jejuni as important cause of infection.•Unusually high attribution to wild bird C. jejuni genotypes were observed.•No large differences in genotype distributions were observed between 2000 and 2008.

Campylobacter jejuni is an important food-borne pathogen, with a global distribution. It can colonize numerous host species, including both domestic and wild animals, but is particularly associated with birds (poultry and wild birds). For human campylobacteriosis, poultry products are deemed the most significant risk factor for acquiring infection. We conducted a genotyping and host attribution study of a large representative collection of C. jejuni isolated from humans and broilers in Sweden in the years 2000 and 2008. In total 673 broiler and human isolates from 10 different abattoirs and 6 different hospitals were genotyped with multilocus sequence typing. Source attribution analyses confirmed the strong linkage between broiler C. jejuni and domestic human cases, but also indicated a significant association to genotypes more commonly found in wild birds. Genotype distributions did not change dramatically between the two study years, suggesting a stable population of infecting bacteria.