Study on the genetic marker of class 1 integron and the drug-resistant genes associated β-lactam antibiotics in imipenem-resistant Pseudomonas aeruginosa

Objective To investigate the class 1 integron and the drug-resistant genes associated β-lactam antibiotics in imipenem-resistant Pseudomonas aeruginosa(IRPa) isolated from the clinical specimens.Methods The class 1 integron genetic markers(including intI1 and qacE△1-sul1) and 18 kinds of the drug-resistant genes associated β-lactam antibiotics were analyzed from 28 isotated strains of IRPa by PCR and verificated by DNA sequencing.Results In 28 strains of IRPa,the positive rates of intI1,qacE△1-sul1,blaTEM,blaOXA-10 group,and blaCARB were 75.0%,85.7%,71.4%,3.6%,and 3.6%,respectively.blaOXA-10 group and blaCARB were sequenced and determined to be blaOXA-10 subtype ESBL gene(GenBank accession number:AY841859) and blaCARB-3,respectively.The deficiency rate of oprD gene was 89.3%.Genes of blaIMP,blaVIM,blaSHV,blaPER,blaVEB,blaGES,blaMIR,blaDHA,blaSPM,blaGIM,blaOXA-1 group,blaOXA-2 group,blaBEL-1,and blaCTX-M-1 group showed all negative.Conclusion There are very high harbouring rates of the class 1 integron in IRPa isolated clinically,and at least 3 kinds of β-lactamases gene existed including blaTEM,blaOXA-10,blaCARB-3.The oprD gene lack mutation were the main mechanism of Pseudomonas aeruginosa resistant to imipenem.