葡萄球菌属对红霉素和克林霉素的诱导耐药性研究

Inducible Erythromycin Resistance of Staphylococcus to Clindamycin

目的了解泰安地区葡萄球菌属对红霉素和克林霉素的不同耐药表型,测定诱导型克林霉素耐药的发生率及诱导耐药基因。方法按美国临床实验室标准化委员会(NCCLS)推荐的纸片扩散法,测定并判读金黄色葡萄球菌和凝固酶阴性葡萄球菌对红霉素及克林霉素的耐药性,D-试验检测诱导型克林霉素耐药表型,采用聚合酶链反应(PCR)法检测msrA、Vgb、sat4、ermA、ermB、ermC耐药基因。结果326株葡萄球菌属中,162株(44.12%)对红霉素和克林霉素同时耐药;68株(20.86%)对红霉素耐药,对克林霉素敏感,但D-试验阳性;42株(12.88%)对红霉素耐药对克林霉素敏感,但D-试验为阴性;耐红霉素而克林霉素敏感的葡萄球菌属中,显示诱导型克林霉素耐药在耐甲氧西林金黄色葡萄球菌(MRSA)、甲氧西林敏感金黄色葡萄球菌(MSSA)、耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)和甲氧西林敏感凝固酶阴性葡萄球菌(MSCNS)中的比例分别为40.00%、56.25%、63.38%和66.67%;红霉素核糖体甲基化酶基因ermC是诱导耐药的主要基因,占85.29%,ermA、sat4基因均为7.35%,而其他基因均阴性。结论泰安地区耐红霉素葡萄球菌属中诱导型克林霉素耐药的发生率相对较高,临床微生物室应开展D-试验可帮助临床医生正确选用大环内酯类、林可酰胺类和链阳霉素B类(MLSB)抗菌药物。

OBJECTIVE To investigate the resistance of Staphylococcus to erythromyein and elindamyein and detect the percentage and gene for inducible resistance in Tai＇an. METHODS The susceptibilities of Staphylococcus to erythromyein and elindamyein were examined by Kirby-Bauer disc agar diffusion test and the inducible erythromyein resistance to elindamyein was checked by D-test according to the standards of NCCLS, and the resistance genes msrA, Vgb, sat4, ermA, ermB and ermC were detected by using PCR technology. RESULTS Among the 326 strains, 162（44. 12%） were all resistant to erythromyein and elindamyein; 68（20.86%） were resistant to erythromyein and sensitive to elindamyein but they were positive in D-test; 42 （12. 88%） were resistant to erythromyein and sensitive to elindamyein but they were negative in D-test. The rates of inducible resistance of MRSA, MSSA, MRCNS and MSCNS to elindamyein were 40. 00%, 56. 25%, 63. 38% and 66.67%, respectively among the Staphylococcus which were resistant to erythromyein and sensitive to elindarnyeiru The gene ermC was the main one for inducible erythromyein resistance to elindamyein. The percentage of gene ermC was 85.29 % and that of ermC and sat4 either was 7.35 %; all the others were negative. CONCLUSIONS The rate of inducible erythromyein resistance to elindamyein in our area is relatively high, and D-test in clinical microbiology laboratory should be done so that the physicians can select the reasonable MLSB antimierobial agents.