葡萄球菌对头孢硫脒体外敏感性试验研究

In vitro susceptibility of Staphylococcus strains to cefathiamidine

目的研究葡萄球菌对头孢硫脒的敏感性,为临床合理使用该药物提供依据。方法采用肉汤稀释法对分离株进行药敏试验测定其最低抑菌浓度(MIC)值;采用PCR技术检测菌株中耐药基因mecA和blaZ的携带情况;分析耐药基因对头孢硫脒MIC的影响。结果从2013年-2017年,尽管本地区葡萄球菌对头孢硫脒的MIC50仅有轻微波动,但MIC90和MIC地区平均值总体上呈缓慢上升趋势;mecA基因是导致葡萄球菌对头孢硫脒耐药的最主要原因,而blaZ基因对头孢硫脒敏感性的影响较小;头孢硫脒对耐甲氧西林金黄色葡萄球菌(MRSA)菌株基本无抗菌活性,而对耐甲氧西林表皮葡萄球菌(MRSE)有一定的体外抗菌效果。结论葡萄球菌对头孢硫脒的敏感性呈下降的趋势,应引起高度重视。

OBJECTIVE To explore the susceptibility of Staphylococcus strains to cefathiamidine so as to provide guidance for reasonable clinical use of the drug. METHODS The drug susceptibility testing was performed for the isolated strains by using micro-broth dilution method so as to determine the minimal inhibitory concentration(MIC) of the strains, the drug resistance genes mecA and blaZ in the strains were detected by means of PCR, and the influence of the drug resistance genes on MIC of cefathiamidine. RESULTS Although the MIC50 value of cefathiamidine to the Staphylococcus strains isolated in this region fluctuated slightly in 2013-2017, the MIC90 and the average MIC displayed general ascending trends. The mecA gene was the leading cause of the resistance to cefathiamidine, while the blaZ gene had less impact on the susceptibility to cefathiamidine. Cefathiamidine did not have antibacterial activity against methicillin-resistant Staphylococcus aureus(MRSA) but had certain in vitro antibacterial effect on methicillin-resistant Staphylococcus epidermidis(MRSE). CONCLUSION The susceptibility of the Staphylococcus strains to cefathiamidine shows a downward trend, which should be attached great importance to.