目的 研究万古霉素对MRSA的SarA基因表达水平和生物膜形成的影响。方法 自本院MRSA心内膜炎患者血培养中收集 获得MERS菌株957，并以此为母本菌株培养获得系列耐药菌株957-V8、957-V16和957-V32。然后采用荧光定量 PCR 方法对这四株MRSA菌株中生物膜形成相关基因SarA mRNA水平进行检测，并进行生物膜形成试验，在570nm处测量结 晶紫染色后生物膜的吸光度，试验均重复3次。结果 体外诱导获得的系列耐药菌株957-V8、957-V16和957-V32的 SarA基因mRNA水平显著高于原代957菌株相比，而且SarA基因mRNA量随着菌株万古霉素MIC值的升高而升高；四株菌 株均可形成生物膜，且诱导菌株957-V8、9527-V16和957-V32生物膜的光密度值显著高于原代菌株957，随着MIC值 的升高，菌株生物膜的光密度值逐渐升高。结论 万古霉素可以诱导MRSA的生物膜增厚，并增强菌株的耐药性。

Objective Evaluation of the effect of vancomycin on SarA gene expression and biofilm formation in MRSA. Methods MERS strain 957 was collected from the blood cultures of patients with MRSA endocarditis in this hospital. A series of drug resistant strains 957-V8, 957-V16 and 957-V32 were obtained by culturing the mother strain with 957. Then the fluorescent gene quantitative assay was used to detect SarA mRNA levels in these four MRSA strains. The biofilm formation assay was performed using crystal violet staining. The absorbance of biofilm after staining was measured at 570nm. The tests were repeated 3 times. Results The SarA mRNA levels of 957-V8, 957-V16 and 957- V32 strains obtained in vitro were significantly higher than those of the original 957 strain.With the increase of MIC of vancomycin, the mRNA of SarA gene was gradually increased. All four strains can form biofilms, and the optical densities of induced strains 957-V8, 9527-V16 and 957-V32 biofilms were significantly higher than those of the original strain 957. With the increase of MIC value, the optical density of strain biofilm gradually increased. Conclusion Vancomycin can induce the increase of drug resistance and biofilm formation of Staphylococcus aureus, which is beneficial to the long-term existence of bacteria in vivo.