Isolation, identification and pathogenicity experiment of Salmonella enterica Serovar Derby from yaks (Poephagus grunniens) with diarrhea in Tibetan Qiang Autonomous Prefecture of Ngawa, China

Abstract:

In order to investigate the pathogen of yaks diarrhea, 16 feces were collected from 4 farms in Hongyuan, Tibetan Qiang Autonomous Prefecture of Ngawa, China. Multilocus sequence typing, serotyping, antimicrobial resistance and pathogenicity experiment were carried out. A total of 16 Salmonella were selected, all strains were Salmonella Derby ST71 and multi-resistant to tetracycline, ampicillin, chloramphenicol and ceftiofur. Salmonella isolated from bloody stool (No. 15XLR) was selected for pathogenicity experiment and the result showed that the half lethal dose of 15XLR was 1.2 × 107 CFU, which can cause severe damage to spleen and intestine according to HE slice. This study investigated the causes of diarrhea in yaks in Hongyuan County, and confirmed that Salmonella Derby can invade yaks except pigs and chickens, suggesting that the prevention and control of diarrhea in yaks should pay attention to infected and the spread of Salmonella in yak population.