红霉素耐药肺炎链球菌基因分布及耐药性分析

目的了解广州地区对红霉素耐药的肺炎链球菌中ermB及mefE基因的分布，比较ermB基因与mefE基因对红霉素耐药的肺炎链球菌的耐药性。方法2001—2004于广州市儿童医院用克林霉素纸片法检测239株对红霉素耐药的肺炎链球菌，并用浓度梯度法检测其耐药性。结果239株对红霉素耐药的肺炎链球菌中，ermB、mefE基因介导的耐药率分别为70.3%(168/239)和29.7%(71/239)。168株ermB基因介导对红霉素耐药的肺炎链球菌，对青霉素(MIC50 0.19μg/mL、MIC90 1.5μg/mL)、阿莫西林/克拉维酸(MIC50 0.19μg/mL、MIC90 1.0μg/mL)、头孢曲松(MIC50 0.19μg/mL、MIC90 0.75μg/mL)、头孢呋辛(MIC50 0.38μg/mL、MIC90 2.0μg/mL)、头孢克洛(MIC50 2.0μg/mL、MIC90 32.0μg/mL)的不敏感率分别为58.4%、1.2%、20.8%、46.5%和51.7%。71株mefE基因介导对红霉素耐药的肺炎链球菌，对青霉素(MIC50 0.5μg/mL、MIC90 1.5μg/mL)、阿莫西林/克拉维酸(MIC50 0.38μg/mL、MIC90 1.0μg/mL)、头孢曲松(MIC50 0.38μg/mL、MIC90 0.75μg/mL)、头孢呋辛(MIC501.0μg/mL、MIC90 3.0μg/mL)、头孢克洛(MIC50 6.0μg/mL、MIC90 48.0μg/mL)的不敏感率分别为67.6%、0、19.7%、59.2%和61.9%。结论广州地区对红霉素耐药的肺炎链球菌其耐药机制以ermB基因介导为主；ermB基因介导的红霉素耐药性高于mefE基因介导的耐药性；ermB和mefE基因介导对红霉素耐药的肺炎链球菌对β 内酰胺类药物存在不同程度的耐药。

The resistant genes distribution and antimicrobial resistance analysis of erythromycin resistant streptococcus pneumoniae.

AbstractObjectiveTo investigate the mechanisms of erythromycin resistant streptococcus pnenoniae and their variable antimicrobial resistance.MethodsClindamycin disks were to screen erythromycin resistant streptococcus pneumoniae mediated by ermB ro mefE genes.Antimicrobial resistance of erythromycin resistant streptococcus pneumoniae mediated by ermB of mefE genes were studied by Etest respectively.ResultsErmB and mefE genes were 70.3%(168/239) and 29.7%(71/239) respectively among 239 strains of erythromycin resistant streptococcus pneumoniae.The rates of resistance to penicillin (MIC50 0.19μg/mL,MIC90 1.5μg/mL),amoxicillin/clavulanic acid (MIC50 0.19μg/mL,MIC90 1.0μg/mL),ceftrixone (MIC50 0.19μg/mL,MIC90 0.75μg/mL),cefuroxime (MIC500.38μg/mL,MIC90 2.0μg/mL),cefaclor (MIC502.0μg/mL,MIC90 32.0μg/mL) of erythromycin resistant streptococcus pneumoniae mediated by ermB were 58.4%,1.2%,20.8%,46.5% and 51.7% respectively,and the resistance rates to penicillin(MIC50 0.5μg/mL,MIC90 1.5μg/mL),amoxicillin/clavulanic acid (MIC50 0.38μg/mL,MIC90 1.0μg/mL),ceftrixone (MIC50 0.38μg/mL,MIC90 0.75μg/mL),cefuroxime (MIC501.0μg/mL,MIC90 3.0μg/mL),cefaclor (MIC506.0μg/mL,MIC90 48.0μg/mL) of erythromycin resistant streptococcus pneumoniae mediated by mefE were 67.6%,0,19.7%,59.2% and 61.9% respectively (including decreased susceptibility).ConclusionErythromycin resistant streptococcus pneumoniae mediated by ermB is predominant in Guangzhou,the level of erythromycin resistance mediated by ermB is usually higher due to mefE.Erythromycin resistant streptococcus pneumoniae mediated by ermB or mefE genes also has β lactam resistance in various level.