浙江宁波分离株泛耐药鲍氏不动杆菌常见耐药基因研究

Investigation of resistant genes in pandrug-resistant Acinetobacter baumannii isolated from Ningbo,Zhejiang Province

目的调查泛耐药鲍氏不动杆菌耐药基因存在状况和菌株间的亲缘关系。方法收集2013年1-12月浙江省宁波大学医学院附属医院患者标本中分离的泛耐药鲍氏不动杆菌33株,采用聚合酶链反应(PCR)的方法分析33种β-内酰胺类常见耐药基因、3种β-内酰胺类耐药基因与插入序列连锁检测、14种氨基糖苷类常见耐药基因、1种喹诺酮类常见耐药基因、1种获得性外排泵泵蛋白基因,再对检测结果作样本聚类分析。结果 33株泛耐药鲍氏不动杆菌每株均检出β-内酰胺类、氨基糖苷类药物耐药基因和喹诺酮类药物作用靶位gyrA基因的突变,共检出4种β-内酰胺类耐药基因:blaTEM、blaADC、blaOXA-23群、blaOXA-51群;5种氨基糖苷类耐药基因:armA、aac(3)-Ⅰ、aac(6′)-Ⅰb、ant(3″)-Ⅰ、aph3′-Ⅰ;喹诺酮类药物作用靶位gyrA基因均存在突变;外排泵泵蛋白基因adeB检出率高;β-内酰胺类耐药基因与插入序列连锁检测结果为:32株blaADC阳性菌29株blaADC-ISaba1阳性(连锁检测阳性率90.6%);33株blaOXA-23群阳性菌株blaOXA-23群-ISaba1均阳性(连锁检测阳性率100.0%);33株blaOXA-51群阳性菌株blaOXA-51群-ISaba1均阴性(连锁检测阳性率0.0);样本聚类分析显示,6号株为外簇群不携带blaTEM、blaADC、adeB等基因,其余为同一簇群(A簇群),A-1簇群blaADC-ISaba1检测阳性,即blaADC由ISaba1介导,A-2簇群blaADC-ISaba1检测阴性,即blaADC不由ISaba1介导。结论泛耐药鲍氏不动杆菌菌株聚集现象明显,并存在5个克隆传播,获得菌株之间的亲缘关系对医院感染实时监测和控制意义重大。

OBJECTIVE To investigate the conditions and phylogenetic analysis among a group of pandrug-resistant Acinetobacter baumannii （A. Baumannii）. METHODS A total of aa strains of pandrug-resistant A. baumannii from Jan. 2013 to Dec. 2013 were collected from the affiliated hospital of school of medicine of Ningho University. Then, resistance genes were analyzed by PCR, including 33 kinds of beta-lactamase genes, 3 kinds of linkage de- tection of beta-lactamase genes and insertion sequences, 14 kinds of resistant genes to aminoglycosides, 1 kind of resistant genes to quinolones, and 1 kind of acquired efflux gene. In addition, sample cluster analysis were per- formed. RESULTS Resistant genes to beta-lactams, aminoglycosides, quinolones were all positive in every strain. Furthermore, 4 kinds of beta-lactam-resistance genes （blaTEM, blaADC, blaOXA-23 group, blaOXA-51 group）, 5 kinds of aminoglycoside-resistance genes （armA, aac（3）- I , aac（6＇）- I b, ant（3＂）- I , aph3＇- I ） were positive, mutations existed in all gyrA, and positive rates of adeB were high. Linkage detection of beta-lac- tamase gene and insertion sequence showed that positive rates of blaADC-ISaba 1, blaOXA-23 group-ISabal, and blaOXA-51 group -ISabal were 90.6M, 100.0%, and （3.0%, respectively. Sample cluster analysis showed that strain No. 6 was a outer cluster, and other strains were in cluster A, and blaADC were mediated by ISabal in cluster A-l, while blaADC were not mediated by ISabal in cluster A-2. CONCLUSION Agrreegation in this group of pandrug-resistant A. baumannii and 5 clones existed. So it is important to monitor and control nosocomial in- fection in time depending on phylogenetic analysis among strains.