多重耐药性铜绿假单胞菌耐药基因及菌株聚类分析

Resistant Genes and Cluster Analysis in Multidrug-resistant Pseudomonas aeruginosa

目的了解临床分离的铜绿假单胞菌中β-内酰胺类、氨基糖苷类等抗菌药物耐药相关基因存在状况和菌株的亲缘性。方法药敏试验用PhoenixTM-100鉴定药敏系统检测,β-内酰胺类抗菌药物耐药相关基因、氨基糖苷类抗菌药物修饰酶基因和消毒剂抗性基因,采用PCR检测并用DNA测序仪证实。结果190株铜绿假单胞菌对氨苄西林/舒巴坦、哌拉西林、哌拉西林/他唑巴坦、头孢噻肟、头孢他啶、头孢吡肟、亚胺培南、美罗培南的耐药率分别为98.9%、59.5%、45.8%、77.4%、34.2%、38.4%、15.3%、6.8%;对环丙沙星、左氧氟沙星耐药率为15.3%、21.0%;21株铜绿假单胞菌中blaVEB、blaGES和blaCARB阳性率分别为9.5%、9.5%和57.1%,oprD2基因缺失率达95.2%;TEM、SHV、OXA、PERI、MP、VIM、SPM、GIM和DHA编码基因均阴性;aac(6′)-Ⅰ、aac(6′)-Ⅱ和ant(2″)-Ⅰ,在21株铜绿假单胞菌中的阳性率分别为9.5%、61.9%和66.7%,qacE△1-sul1基因的阳性率为66.7%。结论临床分离的铜绿假单胞菌已携带多种耐药基因,oprD2基因缺失可能是铜绿假单胞菌耐受亚胺培南重要原因,聚类分析表明存在克隆传播医院感染。

OBJECTIVE To investigate resistant genes encoding β-1actamases and aminoglycoside modifying enzymes in Pseudomonas aeruginosa isolated from clinical specimens, and phylogenetic analysis was performed. METHODS Antimicrobial susceptibility test was performed by PhoenixYM-100 system. Resistant genes encoding β-1actamases, aminoglycoside modifying enzymes and antiseptic resistance were detected by PCR amplification and verified by DNA sequencer. RESULTS The resistant rates of β-1actams including ampicillin/sulbactam, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem and meropenem in 190 strains of P. aeruginosa were 98.9%, 59.5%, 45.8%, 77.4%, 34.2%, 38. 4%, 15.3% and 6.8%, respectively. Ciprofloxacin and levofloxacin still showed powerful activities with resistance being 15.3% and 21.0%. The positive rates of blavEB, blaGES and blacARB genes were 9. 5%, 9. 5% and 57. 1% in 21 isolates. Twenty strains lost oprD2 genes. However,the β-1actamase genes of TEM, SHV, OXA, PER, IMP, VIM, SPM, GIM and DHA were not found. Three resistant genes encoding aminoglycoside-modifying enzymes were found in 21 isolates, such as aac（6＇）-Ⅰ , aac（6＇）- Ⅱand ant（2＂）- Ⅰ , and they accounted for 9.5%,61.9% and 66.7%, respectively. The positive rate of qacE△1-sull genes was 66.7% in 21 isolates. CONCLUSIONS P. aeruginosa isolated in clinic has carried many resistant genes. The loss of oprD2 gene may be the important cause of P. aeruginosa resistant to imipenem. Cluster analysis indicates that the spread of clones occurred in our hospital.