痰标本分离革兰阴性杆菌整合子分布及分型研究

Distribution and typing of integrons in gram-negative bacilli from sputum

目的研究临床痰标本分离革兰阴性杆菌中整合子的分布与分型。方法用Ⅰ类、Ⅱ类和Ⅲ类3种整合酶基因通用引物扩增398株痰标本分离革兰阴性杆菌的相应基因;用琼脂对倍稀释法检测临床菌株的MIC。结果Ⅰ类整合酶基因总阳性率为48.7%,Ⅱ类整合酶基因总阳性率为2.3%,未检出Ⅲ类整合酶基因阳性菌株,Ⅰ类和Ⅱ类整合子同时阳性率为1.5%。肠杆菌科细菌Ⅰ类整合酶基因阳性率为69%,Ⅱ类整合子阳性率为2.7%;非发酵菌中Ⅰ类整合子阳性率为34%,Ⅱ类整合子阳性率为1.8%。在肠杆菌科细菌中,Ⅰ类整合酶基因阳性菌株对多种抗菌药物的耐药率均明显高于阴性菌株。结论在痰标本分离的革兰阴性杆菌中,肠杆菌科细菌Ⅰ类整合子的携带率高于非发酵菌,Ⅱ类整合子则无明显区别。

Objective To study the distribution and typing of integrons in gram-negative bacilli from sputum. Methods To amplify Class Ⅰ, 2 and 3 integrase genes in 398 gram negative bacilli isolates collected from sputum by polymerase chain reaction with universal primers of the 3 genes. The minimum inhibitory concentration of antimicrobial agents was determined by agar dilution method. Results Class Ⅰ integrase gene was identified in 48.7% of clinical isolates, class 2 integrase gene in 2.3%, class 3 integrase gene in 0% , class Ⅰ integron ＋ class 2 integron in 1.5% of clinical isolates. The prevalence of class Ⅰ integron was 690% and class 2 integron 2.7% in Enterobacteriaceae, and 34%, 1. 8% in nonfermentative bacteria respectively. The resistance rates of class Ⅰ integron positive strains to many antimicrobial agents were significantly higher than the resistance rates of integron negative strains in Enterobacteriaceae. Conclusions Of the gram negative bacilli isolated from sputum, the prevalence of class Ⅰ integrons in Enterobacteriaceae was higher than that in nonfermentative bacteria. There was no difference in terms of the prevalence of class 2 integrons. Class Ⅰ integron is one of the important factors for drug resistance and multi drug resistance in bacteria.