[Objective]A farm in Xinjiang reported sheep exhibiting symptoms of lethargy,persistent coughing,audible wheezing,and noticeable weight loss.The research aimed to identify the causative pathogen responsible for these clinical signs.[Methods]Four lung tissue samples from infected sheep were submitted for diagnostic examination.Isolation and culture of a bacterial strain from the samples were performed,followed by the observation of cultural characteristics.A comprehensive analysis was conducted,including polymerase chain reaction(PCR)for bacterial identification,serotype determination,antimicrobial susceptibility testing,and evaluation of pathogenicity using animal models.[Results]A gram-negative bacterium was isolated from the lung samples.Its morphological characteristics strongly suggested it to be Mannheimia haemolytica,commonly referred to as hemolytic Mannheimia spp.Confirmatory PCR analysis identified the bacteria as Mannheimia haemolytica,with the serotype specified as A2.Antimicrobial sensitivity profiling demonstrated that the strain was sensitive to several antibiotics,namely penicillin,cefazolin,and ampicillin.Pathogenicity assays conducted in murine models showed 100%mortality within 15 hours post-infection,asserting the strain's pathogenic potential.[Conclusion]The offending pathogen responsible for the sheep's symptoms was pinpointed as serotype A2 Mannheimia haemolytica.The susceptibility of this strain to commonly used antibiotics such as penicillin,cefazolin,and ampicillin provides a therapeutic avenue for effectively managing and curtailing this infectious condition in the sheep population.
NETL
NSTL
维普
万方数据
