红霉素耐药肺炎链球菌基因分布及耐药性分析

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

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(MIC500·19μg/mL、MIC901·5μg/mL)、阿莫西林/克拉维酸(MIC500·19μg/mL、MIC901·0μg/mL)、头孢曲松(MIC500·19μg/mL、MIC900·75μg/mL)、头孢呋辛(MIC500·38μg/mL、MIC902·0μg/mL)、头孢克洛(MIC502·0μg/mL、MIC9032·0μg/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(MIC500·5μg/mL、MIC901·5μg/mL)、阿莫西林/克拉维酸(MIC500·38μg/mL、MIC901·0μg/mL)、头孢曲松(MIC500·38μg/mL、MIC900·75μg/mL)、头孢呋辛(MIC501·0μg/mL、MIC903·0μg/mL)、头孢克洛(MIC506·0μg/mL、MIC9048·0μg/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。

Objective To investigate the mechanisms of erythromycin-resistant streptococcus pnenoniae and their variable antimicrobial resistance. Methods Clindamycin 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. Results ErmB 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 resist- ance 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 （ MIC50 0. 38μg/mL, MIC90 2.0μg/mL）, cefaclor （ MIC50 2. 0μg/mL, MIC50 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, MIC50 1.5μg/mL） ,amoxicillin/clavulanic acid （ MIC50 0. 38μg/mL,MIC50 1.0μg/mL） ,ceftrixone （ MIC50 0. 38μg/mL, MIC50 0. 75μg/mL）, cefuroxime （ MIC50 1.0μg/mL, MIC50 3.0μg/mL）, cefaclor （ MIC50 6. 0μg/mL, MIC50 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 ）. Conclusion Erythromycin-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-1aetam resistance in various level.