葡萄球菌属的耐药性及耐药机制探讨

目的探讨诱导型克林霉素耐药测定的临床价值和评价头孢西丁纸片扩散法检测耐甲氧西林葡萄球菌mecA基因。方法用NCCLS规定的D试验法检测红霉素和克林霉素的耐药表型,以及根据2004年版的NCCLS推荐使用头孢西丁(30μg)纸片扩散法检测葡萄球菌mecA基因。结果所有390株葡萄球菌属细菌中,218株(55.9%)对红霉素和克林霉素均耐药(cMLS),70株(17.9%)对红霉素耐药,克林霉素敏感,但D试验阳性(iMLS),79株(20.3%)对红霉素耐药,克林霉素敏感,但D试验阴性(MS);头孢西丁纸片扩散法筛选的390株葡萄球菌属细菌,有272株为MRS。结论开展D试验检测葡萄球菌属中红霉素对克林霉素的诱导耐药性可帮助临床医师正确选用大环内酯类、克林霉素类抗菌药物,同时用头孢西丁纸片扩散法可以成为临床实验室常规开展筛选MRS的方法。

Resistance of Staphylococcus and Its Mechanism

OBJECTIVE To investigate the clinical practicability of inducible clindamycin resistance and to evaluate the clinical value of cefoxitin disk diffusion method in detecting the mecA gene of meticillin-resistant Staphylococcus(MRS). METHODS Resistant phenotypes were classified with erythromycin and clindamycin discs using the D test method and the cefoxitin disk diffusion method in detecting mecA gene of the staphylococcus. RESULTS Of all 390 Staphylococcus strains,218 strains(55.9 %) were resistant to erythromycin and clindamycin(cMLS).Seventy strains(17.9 %) which were resistant to erythromycin but susceptible to clindamycin showed the positive D test results(iMLS),79 strains(20.3 %) resistant to erythromycin but susceptible to clindamycin showed the negative D test results(MS).From 390 strains of clinical isolated staphylococcus,which using the cefoxitin disk diffusion method,272 strains were MRS. CONCLUSIONS Using the D test method to investigate the inducible resistance to erythromycin and clindamycin in the Staphylococcus strains,which could help the doctors choose correctly the antibiotics such as macrolides and clindamycin.At the same time,cefoxitin disk diffusion method can be used reliably by the clinical laboratory in detecting and conforming MRS.