Genotypes and metallo-beta-lactamases carriage in carbapenem-resistant Pseudomonas aeruginosa isolated from children in Moscow

Abstract

Objective. To characterize the population structure and determine the genetic mechanisms of carbapenem resistance in nosocomial isolates of P. aeruginosa collected in Moscow in 2012-2016. Materials and methods. Carbapenem-resistant isolates were collected in two pediatric hospitals in Moscow. Antibiotics susceptibility of P. aeruginosa isolates was assessed using the E-tests and disk-diffusion method. Multilocus sequence typing (MLST) was used for genotyping of the isolates. The presence of metallo-betalactamase (MBL) genes was determined using real-time PCR. Results. All isolates had multidrug resistant phenotype. MLST identified 21 unique sequence types (ST). Five sequence types (ST111, ST235, ST446, ST654 and ST2592) prevailed in the population structure, composing 78% of the carbapenem resistant P. aeruginosa. 50 (57%) isolates carried blaVIM-2 gene; the presence of other carbapenemase genes, including blaNDM and blaIMP, was not detected. Conclusions. The genetic structure of carbapenem-resistant P. aeruginosa population is characterized by a diversity of unrelated sequence-types with the predominance of a small number of the high epidemic risk international clones: ST654, ST111 and ST235. The main carbapenem resistance mechanism of P. aeruginosa isolates was the production of VIM-2 carbapenemase.

Keywords

• pseudomonas aeruginosa
• antibiotic resistance
• carbapenems
• metallo-beta-lactamases
• mlst