多药耐药鲍氏不动杆菌可移动遗传元件研究

目的了解临床分离的多药耐药鲍氏不动杆菌(MDR-ABA)可移动遗传元件的存在状况。方法收集住院患者中分离的62株MDR-ABA,采用聚合酶链反应(PCR)及序列分析的方法检测接合性质粒遗传标记(traA、trbC),插入序列(ISaba1、IS1133、ISEcp1),转座子遗传标记(merA、tnsA),整合子遗传标记(intⅠ1、intⅠ2、intⅠ3)等可移动遗传元件,并将先前报道的转座子遗传标记新型转座酶基因tnpU、tnp513合并总结分析。结果62株MDR-ABA中,4种可移动遗传元件基因ISaba1、tnpU、tnp513和intⅠ1阳性株数分别为55株(88.7%)、34株(54.8%)、35株(56.5%)和34株(54.8%),其余8种基因均阴性;55株(88.7%)至少检出1种基因,33株(53.2%)同时4种基因阳性。结论MDR-ABA存在严重的β-内酰胺类、氨基糖苷类、喹诺酮类、四环素和复方新诺明等多药耐药状况可能与ISaba1、tnpU、tnp513和intⅠ1等可移动遗传元件标记携带率高有关,在MDR-ABA中检出ISaba1、tnpU、tnp513等3种基因插入序列和转座酶基因为国内首次。

Mobile Genetic Elements in Multidrug-resistant Acinetobacter baumannii

OBJECTIVE To investigate the distribution of mobile genetic elements in multidrug-resistant Acinetobacter baumannii(MDR-ABA)isolated from clinical samples.METHODS Sixty-two strains of MDR-ABA were isolated from inpatients.Then,10 kinds of mobile genetic elements:genetic markers of conjugal plasmids(traA and trbC),insertion sequences(ISaba1,IS1133 and ISEcp1),genetic markers of transposons(merA and tnsA),and genetic markers of integrons(int Ⅰ 1,int Ⅰ 2 and int Ⅰ 3)were analyzed by PCR and verified by DNA sequencing.Combining with genetic markers of transposons(tnpU and tnp513)reported before,all data were analyzed as a whole.RESULTS In 62 strains of MDR-ABA,55 strains(88.7%),34(54.8%),35(56.5%)and 34(54.8%)were detected to carry ISaba1,tnpU,tnp513 and int Ⅰ 1,respectively.However,the rest 8 kinds of genes couldn't be detected out.Furthermore,55 strains(88.7%)were detected out to carry at least 1 kind of gene.In addition,33 strains(53.2%)were detected to carry 4 kinds of genes together.CONCLUSIONS The group of MDR-ABA shows multidrug resistance to beta-lactams,aminoglycosides,quinolones,tetracycline and trimethoprim-sulfamethoxazole antimicrobial agents might result from high rate of mobile genetic elements,such as ISaba1,tnpU,mp513 and int Ⅰ 1,harboring on strains.It's the first report that insertion sequence ISabal,and genetic markers of transposons tnpU and tnp513 are detected in MDR-ABA in China.