Survey on some carbapenems and colistin resistance genes among pseudomonas aeruginosa isolates from burn and cystic fibrosis patients, Tehran, Iran

Abstract

Background: Psseudomonas aerugiona is a major cause of morbidity and mortality among hospitalized patients. Objectives: Because of increasing antibiotic resistance, this study investigated the prevalence of blaIMP, blaPER, blaVEB, blaGES, pmrA, pmrB, and mcr-1 genes in P. aeruginosa isolates among burn and CF (Cystic Fibrosis) patients in Tehran. Methods: During 2016-2017, 80 and 41 isolates of P. aeruginosa were collected from burn and CF patients, respectively, in Shahid Motahhari and Mofid Children’s hospitals. Based on the CLSI protocol, an antibiotic susceptibility test was performed using the disk diffusion method. Then PCR and further sequencing were used to evaluate the frequency of the above-named genes. Results: In both groups, high rates of resistance to amikacin, cefepime, imipenem, ciprofloxacin, ceftazidime, aztreonam, piperacillin, gentamycin and piperacillin-tazobactam were detected. Colistin was determined to be the best choice for treatment. In burn patients, the highest frequency was detected for the blaVEB-1 (55%) gene and the frequencies of blaPER-1, blaIMP-1, and blaGES-1 were 27.5%, 25%, and 13.75%, respectively. In CF patients, the blaPER-1 gene was more common (12.19%), and the frequency rates of blaVEB-1 and blaIMP-1 were 2.43% each. The blaGES-1 gene was not detected. Despite the fact that all of the isolates in both groups had pmrA and pmrB genes, different mutations were detected by sequencing. The mcr-1 gene was not shown in all isolates. Conclusions: Hopefully, by the low frequency of mcr-1 gene and the rate of mutation in pmrAB genes in this study, the rate of resistance can keep low with caution prescription to polymyxins.