关键词: 史氏鲟, 腐生葡萄球菌, 致病性, 耐药性

Abstract: A multi-drug resistant Gram-positive bacterium JY08 was isolated from Acipenser schrenckii lesion sample from a farm in Zhouning, and its evolutionary relationship, drug resistance mechanism and potential pathogenic factors were further studied. Morphological characteristics, 16S rRNA gene sequencing, physiological and biochemical characteristics and analysis of phylogenetic tree were performed to identify strain JY08. The results showed that strain JY08 was basically consistent with the morphological and biochemical characteristics of Staphylococcus saprophyticus. The 16S rRNA gene had a 100% similarity with S. saprophyticus. Strain JY08 was clustered into the one clade with S. saprophyticus by analysis of phylogenetic tree based on the 16S rRNA gene sequence. Combing the physiological and biochemical characteristics, and 16S rRNA gene sequencing, strain JY08 was identified as a member of S. saprophyticus. The results of drug susceptibility test showed that strain JY08 was resistant to 17 drugs belong to β-lactams, macrolides, sulfonamides and lincomycins, etc; sensitive to 11 drugs belong to aminoglycosides, quinolones and chloramphenicols, etc; moderately sensitive to polymyxin B and furazolidone. The analysis of drug resistance genes and virulence factors showed that strain JY08 carried 103 antibiotic resistance genes in 10 categories and 123 virulence related genes in 61 virulence factors. The results of this study provided scientific data for further evaluating the genetic characteristics of this strain of fish infections, and at the same time provided scientific data for the prevention and control of diseases caused by this strain.