Genotypes, carbapenemase carriage, integron diversity and oprD alterations among carbapenem-resistant Pseudomonas aeruginosa from Russia

Abstract

Pseudomonas aeruginosa is a serious opportunistic pathogen demonstrating a high level of resistance to many groups of antibiotics, including carbapenems. This study aimed to characterise the molecular epidemiology and prevalence of mobile genetic elements associated with resistance to carbapenems among P. aeruginosa (CRPA) clinical isolates. Among 145 carbapenem-resistant P. aeruginosa isolates, 34 different sequence types (STs) were detected; the six most common STs were ST654 (24%), ST235 (24%), ST111 (8%), ST446 (6%), ST357 (5%) and ST2592 (a novel single-locus variant of ST357) (4%). A carbapenemase gene was found in 94 isolates (64.8%). The bla_VIM-2 gene was harboured by 64 isolates (44.1%) restricted to ST111, ST235 and ST654, and the bla_GES-type and bla_OXA-10 group genes were each detected in 15 isolates (10.3%); none of other tested carbapenemase genes, including bla_IMP, bla_NDM and bla_GIM, were detected. Among the bla_VIM-2-positive isolates, five types of bla_VIM-2-containing integrons were discovered, including In56, In559, In59-like, In59 and In249. The oprD gene was disrupted by an insertion sequence (IS) in 15.9% of isolates. Overall, five types of IS elements were found (ISPsme1, ISPa1328, ISPa26, ISPst2 and ISPa195). Observed rearrangements within variable regions of bla_VIM-2-carrying integrons in conjunction with the discovery of a novel type of oprD-disrupting IS element illustrate the ongoing evolution of CRPA a, which warrants further investigation.

Keywords: Carbapenem resistance; Carbapenemase; Insertion sequence; Integron; Pseudomonas aeruginosa; oprD.