摘要
目的探讨临床分离的对氨基糖苷类耐药的肠杆菌科细菌产16S rRNA甲基化酶状况,分析其分子流行趋势及其耐药性形成和传播的机制。方法采用纸片扩散法筛选庆大霉素和/或阿米卡星耐药的肠杆菌科细菌;采用聚合酶链反应(PCR)扩增16S rRNA甲基化酶基因、氨基糖苷修饰酶基因、β-内酰胺酶基因;采用质粒接合试验验证16S rRNA甲基化酶的转移性;应用脉冲场凝胶电泳(PFGE)对16S rRNA甲基化酶基因阳性菌株进行分型。结果 201株对庆大霉素和/或阿米卡星耐药的肠杆菌科细菌中共检出38株16S rRNA甲基化酶阳性株(armA基因16株,rmtB基因22株)。其中30株可通过接合试验将耐药质粒转移至受体菌。blaCTX-M-14、blaTEM-1和blaSHV-12可连同armA或rmtB分别转移到11、20和7个接合子中。肺炎克雷伯菌、大肠埃希菌和阴沟肠杆菌分别被PFGE分为4、21和1个型别。结论本研究分离的肠杆菌科细菌16S rRNA甲基化酶以armA和rmtB为主要流行型别,且后者分离率较高。该甲基化酶可导致氨基糖苷类高水平耐药,而且酶编码基因位于质粒上,具有转移性,β-内酰胺酶基因和氟喹诺酮耐药决定因子可随之一同转移。
Objective To investigate the molecular epidemiological characterization and the drug resistance and prevalence mechanism of 16S rRNA methylase in aminoglycoside-resistant Enterobacteriaceae isolated clinically. Methods Gentamicin-and or amikacin-resistant Enterobacteriaceae were screened by disc diffusion method.16S rRNA methylase genes,aminoglycoside modification enzyme genes and beta-lactamase genes were amplified by polymerase chain reaction（PCR）.The conjugal transfer of aminoglycoside-resistant determination was performed.Pulsed-field gel electrophoresis （PFGE）was carried out to analyze genotyping.Results A total of 16 armA gene and 22 rmtB gene 16S rRNA methylase positive isolates were identified.Plasmid conjugation experiments were successful with 30 armA- or rmtB-positive isolates.blaCTX-M-14,blaTEM-1 and blaSHV-12 co-transferred with armA or rmtB were transferred to 11,20 and 7 isolates.Klebsiella pneumoniae,Escherichia coli and Enterobacter cloacae were divided into 4,21 and 1 PFGE patterns.Conclusions armA and rmtB are the main types of 16S rRNA methylase in Enterobacteriaceae isolated in our hospital,and rmtB is more prevalent than armA.This 16S rRNA methylase could mediate high-level resistance to aminoglycoside,and the encoding genes are located on plasmid that could transfer among different species.Beta-lactamase genes and fluoroquinolone resistance could be cotransferred with armA or rmtB gene.
出处
《检验医学》
CAS
2014年第5期528-534,共7页
Laboratory Medicine
基金
国家自然科学基金资助项目(81101282)
