葡萄球菌大环内酯类耐药基因检测及其意义

Detection of macrolide resistance genes of Staphylococcus and its significance

目的了解葡萄球菌对大环内酯类药物表型耐药性和耐药基因以及分析大环内酯类耐药基因与诱导克林霉素耐药的相关性。方法用K—B纸片法检测2004—2005年分离的136株葡萄球菌对红霉素和克林霉素的耐药性，依据NCCLS2004年发布M100-S14的D-试验方法，测定红霉素对克林霉素的诱导耐药率；应用聚合酶链反应（PCR）法检测MsrA、Vgb、Sat4、ermA、ermB、ermC、mphA、MefA／E、ereA、ereB10种耐药基因。结果136株葡萄球菌共栓出MsrA、Sat4、ermC、mphA、ereB5种耐药基因，耐药基因总检出率为80，15％（109／136）。MRSA、MRCNS、MSSA、MSCNS耐药基因的检出率分别为81．25％（13／16）、89，47（68／76）、73，08％（19／26）、50，00％（9／18），耐药基因主要存在于MRCNS。葡萄球菌对红霉素和克林霉素同时耐药株占43．38％，红霉素耐药而克林霉素敏感株占37，50％；D-试验阳性率为25，00％（34／136），阳性株数占红霉素耐药而克林霉素敏感株的66，67％（34／51）。耐药基因MsrA、Sat4、ermC、mphA、ereB的阳性率分别为24．26％、41．91％、56，62％、1．47％、18．38％，其中核糖体甲基化酶基因ermC是诱导克林霉素耐药的主要基因。结论ermC是诱导克林霉素耐药的主要基因，临床微生物实验室应同时开展D试验和耐药基因检测，以指导临床更加合理使用抗菌素。

Objective To detect the macrolicle resistance phenotype and genotype of Staphylococcus isolated in our hospital during 2004 - 2005 and analyze the correlation between the resistance gene and the inducible resistance of Staphylococcus to clindamycine, Methods Susceptibility test of Staphylococcus to erythromycin and clindamycin was performed by Kirby - Bauer disk diffusion test, The erythromycin - inducible clindamycin resistance was detected by D test according to the standard of NCCLS2004, Ten resistant genes such as msrA,vgb,sat4, ermA,ermB,ermC,mefA/E,ereA and ereB genes were detected by using PCR. Restilts Five resistant genes （msrA, sat4,ermC, mphA and ereB） were identified from 136 strains of Staphylococcus and the detection rate of resistance gene was 80.15% （109/136）. The detection rates of MRSA, MRCNS, MSSA and MSCNS were 81.25% （13/ 16）, 89.47% （68/76）, 73.08% （19/26） and 50.00% （9/18）. The resistant genes predominated in MRCNS. 43.38% （59/ 136） Staphylococcus was resistant both to erythromycin and clindamycin, and 37.50% （51/136） was resistant to erythromycin but not to clindamycin. D - test positive rate was 25.00% （34/136） among aU Staphylococcus tested and accounted for about 66.67% （34/51） of strains that resistance to erythromycin but sensitive to clindamycin. The results of test of resistance gene showed that the occurrence of msrA,sat4,ermC,mphA and ereB were 24.26% （33/136）, 41.97% （57/136）, 56.62% （77/136）, 1.47% （2/ 136）, 18.38% （25/136） and the predominant gene for inducible resistance was ermC with the percentage of 70.64% （77/109）. Conclusion The D- test and detection of the resistant genes should be performed in clinical microbiology laboratory in order to guide physicians for reasonably use of antimicrobial agents.