Tracking Clostridium perfringens strains from breeding duck farm to commercial meat duck farm by multilocus sequence typing

Clostridium perfringens (C. perfringens) is an important zoonotic food-borne pathogenic microorganism. Currently, there are many reports on the prevalence of C. perfringens in poultry farms, while few studies on the prevalence and infection source of C. perfringens in egg hatcheries. The present study was undertaken to investigate and track C. perfringens from one breeding duck farm, one duck egg hatchery and one commercial meat duck farm along the production chain. A total of 334 isolates were obtained from 788 samples, including 316 type A strains (94.61 %), 11 type F strains (3.29 %) and seven type G strains (2.10 %). Antimicrobial susceptibility testing revealed that 61.87 % of the tested isolates were multidrug-resistant. Multilocus sequence typing showed that 66 representative isolates encompassed 60 different sequence types (STs), clustered in ten clonal complexes (CCs) and 20 singletons. CC2 was the most popular CC, accounting for 58.82 % (10/17) of the strains from breeding duck farm. Some strains of duck embryos were distributed in the same ST or CC as strains from breeding duck farm and duck egg hatchery, indicating close genetic relationship between them. The study showed that isolates from breeding duck farm had formed a dominant CC through long-term evolution, some duck embryos had been infected with C. perfringens during the incubation period and the infected strains should be from the duck egg hatchery or breeding duck farm with the possibility of vertical transmission. The close relationship between strains from breeding ducks and duck embryos, the high antibiotic resistance of isolates and the presence of cpe-positive or netB-positive isolates indicated that alert should be paid to such risks associated with these.