嗜麦芽寡养单胞菌获得性耐药的机制研究及整合子分布调查  

Acquired drug resistance mechanisms and distribution of intergrons in Stenotrophomonas maltophilia

作　　者：赵苏瑛[1] 杨琳[1] 李鹏飞[1] 曹慧玲[1] 朱小飞[1] 

机构地区：[1]南京中医药大学附属医院检验科,江苏南京210029

出　　处：《中华医院感染学杂志》2017年第2期263-266,271,共5页Chinese Journal of Nosocomiology

摘　　要：目的了解嗜麦芽寡养单胞菌的临床感染特点和药敏性,探讨嗜麦芽寡养单胞菌的获得性耐药机制并检测Ⅰ、Ⅱ、Ⅲ类整合酶基因(intI1,intI2和intI3)及对应的整合子在菌株中的分布,揭示基因分布与细菌耐药性之间的关系。方法收集2015年1-12月自临床分离的嗜麦芽寡养单胞菌400株,剔除重复菌株,对其临床感染特点进行总结分析,煮沸法提取总DNA,采用PCR法扩增qacE△1-sul1、sul2、sul3、intI1、intI2、intI3、dfrA1、dfrA5、dfrA12、dfrA13和Ⅰ、Ⅱ、Ⅲ类整合子可变区。结果临床分离的400株嗜麦芽寡养单胞菌主要来自于痰标本(78.8%),其次是咽拭子(7.5%);分离率最高的科室是ICU(31.3%)、其次是老年科(20.0%);感染病例以男性居多,年龄>60岁者占89%;400株嗜麦芽寡养单胞菌中有49株检出Ⅰ类整合酶基因(12.3%),2株检出Ⅲ类整合酶基因(0.5%),49株检出qacE△1-sul1基因(12.3%),15株检出sul2基因(3.8%);而在40株耐磺胺甲噁唑/甲氧苄啶嗜麦芽寡养单胞菌中有22株检出Ⅰ类整合酶基因(55.0%),13株检出qacE△1-sul1基因(26.5%),6株检出sul2基因(15.0%);对Ⅰ类整合子可变区进行扩增后获得3个大小不同的条带,测序后发现携带是aacA4,ant(3″)和aac(6′)-Ib耐药基因盒。结论Ⅰ类整合子及sul、dfrA基因的存在可以增加嗜麦芽寡养单胞菌对磺胺甲噁唑/甲氧苄啶的耐药性,这是多方面因素协同作用的结果,此外耐磺胺甲噁唑/甲氧苄啶嗜麦芽寡养单胞菌大部分携带有耐季胺盐消毒基因qacE△1,提示随时监测细菌耐药情况并开发新型消毒剂迫在眉睫。OBJECTIVE To understand the clinical characteristics of infections caused by Stenotrophomonas maltophilia, analyze the drug susceptibility, explore the acquired drug resistance mechanisms in the S. maltophilia strains, and detect the typeⅠ, Ⅱ, Ⅲ integrase genes （intI1 ,intI2, and intI3） and their corresponding integrons in the strains so as to define the relationship between the distribution of genes and the bacterial drug resistance. METHODS A total of 400 clinical S. maltophilla isolates were collected from Jan 2015 to Dec 2015, the repetitive strains were excluded, the clinical characteristics of the S. maltophilia infection were analyzed, the total DNA was extracted by using boiling method, and PCR method was employed to amplify qacE△1-sul1, sul2,sul3, intI1, intI2, intI3, dfrA1, dfrAS, dfrA12, and dfrA13 as well as variable regions of class Ⅰ, Ⅱ, and Ⅲ integrons. RESULTS Of the 400 clinical S. maltophilia isolates, 78. 8% were isolated from sputum specimens, and 7. 5% were isolated from throat swab; the isolation rate was highest in ICUs （31.3%）, followed by the geriatric department （20.0%）. The male patients with the infection were dominant, and the patients aged more than 60 years old accounted for 89%. Of the 400 strains of S. maltophilia, 49 （12.3%） were detected positive for class I integrase gene, 2 （0.5%） were detected positive for class III integrase gene, 49 （12.3%） were detected positive for qacE Al-sull gene, 15 （3.8%） were detected positive for sul2 gene. Of 40 strains of sulfamethoxazole-trimethoprim- resistant S. maltophilia, 22 （55.0 %） were detected positive for class Ⅰ integrase gene, 13 （26.5 %） were detected positive for qacE△1-sul1 gene, and 6 （15.0%） were detected positive for sul2 gene. Totally 3 different sizes of bands were acquired after the variable regions of class I integrons were amplified, and aacA4, ant（3″）, and aac （6′）-Ib drug resistance gene cassettes were identified after bands were sequenced. CONCLUSION

关 键 词：嗜麦芽寡养单胞菌 获得性耐药 整合子 

分 类 号：R378[医药卫生—病原生物学]