Carriage of the zoonotic organism <i>Streptococcus suis</i> in chicken flocks in Vietnam
Nguyen Thi Nhung, Nguyen Thi Phuong Yen, Nguyễn Văn Cương, Bach Tuan Kiet, Vo Be Hien, James Campbell, Guy Thwaites, Stephen Baker, Ronald B. Geskus, Philip Ashton, Juan Carrique‐Mas
Abstract
Streptococcus suis infections are an emerging zoonotic agent causing severe disease in humans and a major pig pathogen worldwide. We investigated the colonization of S. suis in healthy chickens in different flocks (n = 59) as well as in-contact pigs in farms with S. suis-positive chickens (n = 44) in the Mekong Delta of Vietnam. Streptococcus suis was isolated from 20 (33.9%) chicken flocks and from all pigs investigated. Chicken isolates formed a distinct genotypic cluster compared with pig and human strains, although two chicken isolates (10%) clustered with pig isolates. Chicken isolates had unusually high levels of resistance against tetracycline (100%), clindamycin (100%) and erythromycin (95%); and intermediate resistance against penicillin (35%) and ceftriaxone (15%). Our findings suggest that chickens may potentially represent a source of S. suis infection to in-contact humans and pigs.