Antimicrobial resistance and prevalence of Metallo-β-lactamase genes IMP-1, VIM-1 and class 1 integron in clinical isolates of Pseudomonas aeruginosa

The ever-increasing resistance to beta-lactame antibiotic in opportunistic Pseudomonas aeruginosa bacteria considered as one of the important factors of death of hospital-acquired infections. This study was performed for determine the antibiotic resistance and prevalence of IMP-1 and VIM-1 metallo-beta-lactamase and integron class I genes in clinical isolates of Pseudomonas aeruginosa.

In this descriptive-analytical study, 200 Pseudomonas spp. isolates from blood, urine, ulcer, eye and sputum infections were collected from Arsanjan hospital in Fars province in south –west of Iran during April-September 2016. After confirmation genus of bacterial by biochemical and 16S rRNA tests, and isolation of Pseudomonas aeruginosa by specific primer of lasI Gene, antibiotic susceptibility was done according to diffusion disk assay and CLSI procedure, the presence of blaVIM, blaIMP and Int-1 genes were determined by PCR.

The results of phenotypic and genotypic tests led to the isolation of 107 isolates of Pseudomonas aeruginosa that the highest resistance with (79.38%) for cefepime and the lowest resistance with (13.08%) for tobramycin. Out of 107 isolates, 10 (9.35%) isolates were carrying class1 Integron,19 (17/76%) isolates carrying IMP gene, 23 (21.5%) isolates carrying VIM gene, 4 (3.74%) isolates carrying IMP gene and integron class1, 11 (10.28%) isolates carrying VIM gene, and class1 intgron, 15 (14.02%) isolates carrying both IMP, VIM and 12 (11.22%) isolates simultaneously were carrying each three genes, VIM, IMP and class1 integron. 13 (12.15%) isolates did not have none of these three genes, VIM, IMP, class1 integron.

The results showed increased multidrug resistance and simultaneous presence of one or two IMP, VIM and Int-1 genes in Pseudomonas aeruginosa strains. Int-1 has the ability to transduce resistance genes and create resistant populations.