摘要
目的了解16S rRNA甲基化酶基因在广泛耐药(XDR)铜绿假单胞菌临床株中的分布及此类耐药基因周边结构。方法收集XDR铜绿假单胞菌59株,琼脂稀释法测定MIC,PCR方法检测16S rRNA甲基化酶基因(armA,rmt A,rmtB,rmtC,rmtD,rmtE,npmA),ERIC-PCR方法进行同源性分析,并对检出的16S rRNA甲基化酶基因armA和rmtB进行周边序列分析。结果 59株XDR铜绿假单胞菌临床分离株中,16S rRNA甲基化酶基因总检出率62.7%(37/59),rmtB的检出率略高于armA,未检出其他甲基化酶基因。根据ERIC-PCR结果受试临床株可分为19个型别。17株检出armA基因菌株分布在3个克隆,其中15株(88.2%)集中在一个克隆(克隆D);而rmtB基因散布于9个克隆。基因周边序列分析显示,armA基因位于一个含多种转座酶的移动元件上,其与大肠埃希菌和鲍曼不动杆菌携带的armA阳性质粒序列一致性达99%;rmtB基因也位于一个含转座酶的移动元件上,其与大肠埃希菌和肺炎克雷伯菌携带的rmtB质粒序列高度一致。结论 16S rRNA甲基化酶基因在XDR铜绿假单胞菌分离株中分布广泛,均在对庆大霉素高度耐药的菌株中检出。armA在铜绿假单胞菌中存在克隆传播。
Objective To profile 16S rRNA methylase genes and the flanking sequences in extensively drug resistant （XDR） Pseudomonas aeruginosa. Methods A total of 59 strains of XDR P. aeruginosa were collected. MICs of antimicrobial agents against these strains were determined by agar dilution method. The genes encoding 16S rRNA methylase （armA, rmtA, rmtB, rmtC, rmtD, rmtE, and npmA） were analyzed by PCR. The homology of strains was studied by enterobacterial repetitive intergenic consensus-polymerase chain reaction （ERIC-PCR）. The structure of armA and rmtB flanking regions were characterized. Results The overall prevalence of armA or rmtB genes was 62.7% （37/59） in XDR P. aeruginosa isolates, specifically armA positive in 17 strains and rmtB positive in 22 strains. The rmtA, rmtC, rmtD, or npmA gene was not identified in any strain. ERICPCR generated 19 types （or clones） from the 59 strains. The 17 armA-positive strains were distributed in 3 clones, and 88.2% of the armA-positive strains （15） belonged to clone D. The rmtB gene was dispersed in 9 clones. Flanking sequence analysis demonstrated that armA gene was located in a mobile element carrying multiple transposases. The sequence of the mobile element showed 99% similarity with the sequence of armA-positive plasmid carried by E. coli and A. baumannii.The rmtB gene was also located in a mobile element containing multiple transposases. The sequence of the mobile element was highly consistent with that of rmtB-positive plasmid carried by E. coli and K. pneumoniae. Conclusions The genes encoding 16S rRNA methylase are prevalent in XDR P. aeruginosa strains. All the genes were identified in high-level gentamicin-resistant strains.Clonal dissemination may explain the spread of armA among P. aeruginosa isolates.
作者
袁瑾懿
余慧
郭燕
徐晓刚
YUAN Jinyi, YU Hui, GUO Yan, XU Xiaogang.(Institute of Antibiotics, Huashan Hospital, Fudan University;Key Laboratory of Clinical pharmacology of Antibiotics, National Health and Family Planning Commission of thePeople＇s Republic of China, Shanghai 200040, Chin)
出处
《中国感染与化疗杂志》
CAS
CSCD
北大核心
2018年第3期273-277,共5页
Chinese Journal of Infection and Chemotherapy
基金
国家自然科学基金(81202593)
