羊源性金黄色葡萄球菌的分离鉴定和耐药性分析OA北大核心CSTPCD

To determine the cause of mastitis in dairy goats,bacteria were isolated and purified from the milk samples submitted for testing.Biochemical identification,16S rRNA PCR amplification,serotype identification,drug sensitivity test,and pathogenicity test were used to identify the pathogens.The results showed that gram-positive spherical bacteria arranged in grape-like clusters were observed under gram staining.Biochemical identification and 16S rRNA PCR amplification and sequencing confirmed 2 strains of Staphylococcus aureus,named BJ1 and BJ2,respectively,and both were serotype 8.The drug sensitivity test results showed that the isolated strains were sensitive to tetracycline,levofloxacin,minocycline,erythromycin,oxacillin,nitrofurantoin,norfloxacin,ciprofloxacin,compound sulfamethoxazole,clindamycin,clarithromycin,chloramphenicol,and penicillin.They were moderately sensitive to spectinomycin and resistant to polymyxin B.The mouse pathogenicity test showed that all mice inoculated with the isolated strains died within 24 hours.Gross examination of the dead mice revealed congestion,hemorrhage,and mucosal adhesion in various tissues and organs.Staphylococcus aureus was isolated from the internal organs,which had 100％homology with the inoculated bacteria,indicating that the bacteria had certain pathogenicity.In conclusion,Staphylococcus aureus is the main pathogen causing mastitis in dairy goats,which provides a reference for clinical drug administration of Staphylococcus aureus.