肺炎链球菌耐药基因ermB、mefA、tetM与转座子整合酶基因intTn的检测  

Distribution of resistance genes ermB,mefA,tetM and the integrase gene intTn of Tn1545 in Streptococcus pneumoniae

作　　者：杨慧[1] 杨永弘[1] Elisabet Nielsen 俞桑洁[1] 袁林[1] 王咏红[1] 沈叙庄[1] 

机构地区：[1]首都医科大学附属北京儿童医院儿科研究所微生物免疫室,北京100045 [2]Gothenburg University

出　　处：《中华微生物学和免疫学杂志》2005年第8期677-682,共6页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金资助项目(30271377);首都医学发展基金重点支持项目(2002001)

摘　　要：目的研究耐药基因ermB、mefA、tetM与转座子整合酶基因intTn在携带肺炎链球菌的北京儿童中分布特点。方法对185株呼吸道感染患儿鼻咽部分离的肺炎链球菌进行以下检测:Etest、琼脂稀释或纸片扩散法测定对大环内酯类、四环素、β内酰胺类及头孢类等15种抗生素的药物敏感性。PCR检测大环内酯类耐药基因ermB和mefA,四环素耐药基因tetM以及转座子Tn1545的整合酶基因intTn。结果185株肺炎链球菌的药敏结果显示,对红霉素、克林霉素、四环素和复方磺胺甲基异唑的耐药率较高,分别为78.9%、76.2%、86.0%和78.7%,对阿莫西林克拉维酸、头孢克洛、头孢曲松和头孢呋辛耐药率较低,分别为2.2%、15.5%、2.8%和14.1%。所有红霉素耐药株均检出ermB和或mefA,其中79.5%为ermB阳性,17.8%为ermB和mefA同时阳性,2.7%为mefA阳性。tetM基因在分离株中的阳性率是87%,四环素耐药组的tetM基因携带率是96.9%,高于敏感组(26.9%)。四环素耐药株的红霉素耐药率(90.0%)亦高于敏感株组(11.5%)。87.6%的肺炎链球菌存在intTn基因,intTn基因阳性组的红霉素、四环素、氯霉素、复方磺胺甲基异唑和环丙沙星的耐药率较intTn基因阴性组高。分离株最常见的基因组合是intTn+tetM+ermB,占58.4%。结论北京地区呼吸道感染儿童鼻咽部肺炎链球菌耐大环内酯类抗生素的主要原因是ermB编码的23SrRNA甲基化酶致靶位改变。tetM基因编码蛋白质的核糖体保护作用,是肺炎链球菌四环素耐药的重要机制。接合性转座子Tn1545的存在与菌株的红霉素和四环素耐药关系密切,可能是肺炎链球菌多重耐药的重要机制之一。Objective To investigate the distribution of resistance genes ermB, mefA, tetM and the integrase gene intTn of Tn1545 in Streptococcus pneumoniae. Methods The antimierobial sensitivity to 15 antibiotics of 185 Streptococcus pneumoniae isolates was tested. PCR was used to detect the macmlide resistance genes ermB and mefA, tetracycline resistance genes tetM, and the integrase gene intTn of Tn1545. Results Of the 185 pneumococcal isolates, the resistance rates to erythromycin, clindamycin, tetracycline and sulphamethoxazole/trimethoprim were 78.9%, 76.2%, 86.0% and 78.7% respectively. For amoxicillin/clavulanic acid, cefaclor, ceftriaxone and cefuroxime, the resistance rates were 2.2%, 15.5%, 2.8% and 14.1% respectively. All erythromycin-resistant isolates had ermB and/or mefA gene of these strains, 79.5% had ermB, 17.8% had both ermB and mefA, and 2.7% had mefA of the 185 isolates, 87% was positive for the tetracychne resistance gene tetM. The presence of tetM gene in tetracychne-resistant strains was higher（96.9%） than those in tetracycline-susceptible strains（26.9%）. So did the erythromycin resistance rates in tetracycline-resistant strains （90.0%） than those in tetracycline-sensitive strains（ 11.5% ）. The intTn gene was detected in 87.6% of the 185 test strains. The most prevalent patterns associated with the four test genes of the strains, were those had intTn, tetM and ermB （58.4% ）. Cozwdusion Resistance to macmhde in Streptococcus pneumoniae collected from nasopharyngeal sites in children with respiratory tract infection in Beijing Children＇s Hospital was generally mediated by methylation of 23S rRNA via ermB methylase. Pneumococcal resistance to tetracycline was predominantly due to ribosomal protection encoded by terM. There was a significant association of the ermB and terM genes with Tn1545-related elements.

关 键 词：肺炎链球菌 大环内酯类 四环素 转座子 TETM基因 PCR检测 ermB 耐药基因 酶基因 大环内酯类抗生素 

分 类 号：R378[医药卫生—病原生物学]