Metallo-B-lactamase genes as Determinants of resistance to Carbapenems By clinical isolates of Pseudomonas aeruginosa

Abstract

Multidrug resistant Pseudomonas aeruginosa (MDRPA) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) are difficult to treat. Carbapenem resistance is due to multiple mechanisms and among these mechanisms production of carbapenemases is the most important. This study aimed to investigate the prevalence of carbapenemase encoding genes that were associated with CRPA. Bacterial isolation, identification and antibiotic sensitivity were performed. Selected CRPA isolates were investigated for the presence of specific carbepenemase-encoding genes. Mutation was induced by exposuring the bacterial cells to UV radiation. Among the investigated 54.5% CRPA isolates (12/22) were harboring carbapenemases producer genes. KPC, VIM and IMP genes were detected in (11/22, 50%), (5/22, 22.7%), and (4/22, 18.2%), respectively, while SME, NDM1(using two pairs of primers) and OXA genes were not detected in any of the tested CRPA isolates. In the absence of KPC, IMP and VIM genes in bacterial mutants, MIC for carbapenems were decreased from ≥ 16 to ≤ 2 mg/l. In the current study, the prevalence of carbapenemase encoding genes was relatively high, which was observed in association with high mortality rate. In contrast to recent publications, KPC and IMP genes were detected in Kuwait hospitals isolates and their impact on resistance was proved. CRPA strains that were induced for mutation by exposure to UV radiation were also treated with SDS and heat to enhance plasmid curing. A lot of significant sequence alignments confirmed PCR results.