鲍曼不动杆菌临床分离株16S rRNA甲基化酶基因研究

Methylase genes associated with 16S rRNA in Acinetobacter baumannii isolated from hospital

目的了解临床分离鲍曼不动杆菌(ABA)氨基糖苷类药物耐药性与16S rRNA甲基化酶基因存在的关系,探讨多药耐药机制。方法收集临床标本20株鲍曼不动杆菌,采用K-B法测定细菌对卡那霉素、阿米卡星、妥布霉素、庆大霉素、奈替米星的敏感性;采用PCR法检测armA、rmtA、rmtB、rmtC和rmtD 5种16S rRNA甲基化酶基因。结果 19株鲍曼不动杆菌对上述5种氨基糖苷类药物全部耐药,1株对阿米卡星敏感,对另外4种表现为中度耐药。基因检测显示armA阳性率为90%,且armA基因存在变异,未检测到rmtA、rmtB、rmtC和rmtD基因。结论鲍曼不动杆菌对氨基糖苷类药物耐药情况严重,16S rRNA甲基化酶基因armA为本次临床分离菌株耐药的主要原因,且armA基因存在变异。

Objective To investigate the antibiotic resistance and 16S rRNA methylase gene of the multidrug- resistant Acinetobacter baumannii （ABA） and discuss the mechanism. Methods The samples of 20 ABA isolates were collected from hospital. K-B method was used to determine the sensitivity to 5 antibacterials including kanamycin, amikacin, tobramycin, gentamicin and netilmicin, and the 16S rRNA methylase genes were analyzed by polymerase chain reaction （PCR）. Results 19 strains of ABA were resistance to 5 antibacterials, while one strain was sensitive to amikacin, and showed moderate resistance to the other 4 antibacterials. Genetic testing showed the positive rate of armA was 90%, and the variation of armA was also detected, however, all isolates were negative for rmtA, rmtB, rmtC and rmtD genes. Conclusion The antibiotics resistance of Acinetobacter baumannii is very serious, and the armA gene would be the main causes of high drug-resistantce to aminoglycosides in this research and one mutant armA sequence was detected.