氨基糖苷类抗生素耐药肠杆菌科细菌16SrRNA甲基化酶基因研究

Study on 16S rRNA methylase gene of Enterobacteriaceae bacteria resistant to aminoglycosides antibiotics

目的研究肠杆菌科细菌的药物敏感性,探讨其对氨基糖苷类抗菌药物的耐药机制。方法收集临床连续分离的对庆大霉素、妥布霉素、阿米卡星三种药物中至少1种耐药的肺炎克雷伯菌43株、阴沟肠杆菌35株、大肠埃希菌57株以及以上三种药物都敏感的对照菌株各20株,PCR法检测16S rRNA甲基化酶基因arm-A、rmt A、rmt B、rmt C、rmt D、npm A。结果所有对阿米卡星耐药的菌株对庆大霉素和妥布霉素均耐药。以上肠杆菌对头孢唑林、氨苄西林及氨苄西林/舒巴坦的耐药率均高于77.3%,对亚胺培南的耐药率低于6.1%;PCR产物测序,43株肺炎克雷伯菌中9株携带arm A基因,占20.9%、10株携带rmt B基因,占23.3%;35株阴沟肠杆菌中12株携带arm A基因,占34.2%、3株携带rmt B基因,占8.6%;57株大肠埃希菌中7株携带rmt B基因,占12.3%。结论肠杆类细菌氨基糖苷类耐药机制与产16S rRNA甲基化酶有关,阿米卡星可能是筛选16S rRNA甲基化酶基因的理想药物。

Objective To investigate the aminoglucoside drug sensitivities of Enterobacteriaceae bacteria and the mechanisms of bacterial resistance. Methods We collected non- repetitive clinical isolates,including 43 strains of Klebsiella pneumoniae,35 strains of Enterobacter cloacae and 57 strains of Escherichia coli,which at least resisted one of the aminoglucoside drugs,including gentamicin（ CN）,tobramycin（ TOB） and amikacin（ AK）,and 20 strains which were sensitive to these three drugs. The genotypes of 16 S rRNA methylase genes arm A,rmt A,rmt B,rmt C,rmt D and npm A were detected by PCR. Results The strains resistant to AK were also resistant to CN and TOB. The drug resistance rates of above- mentioned Enterobacteriaceae bacteria to cefazolin,ampicillin and ampicillin / sulbactam were all higher than 77. 3%,while the drug resistance rates of them to imipenem were all lower than 6. 1%. According to PCR amplification and sequence analysis,there were 9 strains of Klebsiella pneumoniae carried arm A and 10 strains carried rmt B,accounting for 20. 9%（ 9 /43） and 23. 3%（ 10 /43）,respectively. There were 12 strains of Enterobacter cloacae carried arm A and 3 strains carried rmt B,accounting for 34. 2%（ 12 /35） and 8. 6%（ 3 /35）,respectively. There were 7 strains of Escherichia coli carried rmt B,accounting for 12. 3%（ 7 /57）. Conclusions The aminoglycoside resistance mechanisms of Enterobacteriaceae bacteria are correlated with producing 16 S rRNA methylase genes,and AK may be the ideal antibiotic to screen 16 S rRNA methylase genes.