奶牛源金黄色葡萄球菌新疆流行株的耐药特性、毒力基因及分子分型

Study on Resistance Characteristics,Virulence Genes and Molecular Classification of Staphylococcus aureus Isolated from Cows in Xinjiang

旨在了解引起奶牛乳房炎和子宫内膜炎的金黄色葡萄球菌(SA)新疆流行株的耐药性、毒力基因及其分子流行病学特征。对2014—2016年新疆地区155株SA奶牛临床分离株的耐药表型进行分析,并对耐甲氧西林SA(MRSA)进行鉴定;通过PCR技术对SA的耐药基因、毒力基因进行检测及SCCmec、MLST分子分型。结果在155株SA中检出22株MRSA,检出率为14.2%;MRSA流行株的耐药性明显高于甲氧西林敏感SA(MSSA);不同的毒力基因在MSSA和MRSA中的检出率有所差异;SCCmecⅠ为新疆地区SA主要基因型;MLST分型共检出14种ST型,分别为ST188、ST584、ST9、ST805、ST2373、ST968、ST2139、ST1、ST2700、ST903、ST2454、ST2990、ST63、STX,其中ST1和ST9检出率相对较高,在MSSA菌株中ST9型的检出率最高,MRSA菌株中ST1检出率最高。研究表明,新疆地区奶牛源SA中主要流行株为MSSA,但MRSA耐药性更强,且毒力基因分布多样,ST9为MSSA流行株的主要基因型,ST1-SCCmecⅠ为MRSA流行株的主要基因型。

In order to know the antimicrobial resistance, virulence genes and the epidemiological characteristics of Staphylococcus aureus （SA） isolated from cows with mastitis and endometritis. The drug resistance profile for 155 clinical S. aureus isolates were determined using disk diffusion method, and methicillin-resistant Staphylococcus aureus （MRSA） strains were also identified. Antimicrobial genes, virulence genes, SCCmec genotyping and MLST genotyping were detected and analyzed by using PCR method. The results showed that a total of 22 MRSA strains have been detected among 155 SA isolates, with the detection rate of 14.2%. The antimicrobial resistant rates of most MRSA were significantly higher than that of the MSSA strains; and the detection rates of different virulence genes were different between MRSA and MSSA. The SCCmecⅠwas identified as a predominant genotype of SCCmec in Xinjiang region. Fourteen ST genotypes were detected, namely ST188, ST584, ST9, ST805, ST2373, ST968, ST2139, ST1, ST2700, ST903, ST2454, ST2990, ST63 and STX, respectively. ST1 and ST9 had higher detection rates than others. ST9 was higher among MSSA strains and ST1 was higher among MRSA strains. This study showed that SA strains were of multiple resistance with diverse distribution of virulence genes. While ST9 was the predominant genotype among MSSA strains and ST1-SCCmecⅠwas the predominant genotypes among MRSA strains in Xinjiang region.