Mutational basis of Meropenem resistance in Pseudomonas aeruginosa

About authors

Pirogov Russian National Research Medical University, Moscow, Russia

Ostrovityanova, 1, Moscow, 117997, Russia: Correspondence should be addressed: Igor V. Chebotar

About paper

Funding: the study was supported by the Russian Science Foundation (project No. 20-15-00235).

Acknowledgements: the authors thank the Center of Precision Genome Editing and Genetic Technologies for Biomedicine of the Pirogov Russian National Research Medical University for their advice on the research methods.

Author contribution: Chebotar IV — concept, manuscript writing; Bocharova YuA — methods, formal analysis; Chaplin AV — formal analysis of sequencing data; Savinova TA — formal analysis of sequencing data; Vasiliadis YuA — methods, sequencing; Mayansky NA — concept, manuscript editing.

Compliance with ethical standards: the study was performed in full compliance with the principles of the Declaration of Helsinki and the standards for handling opportunistic pathogens.

Received: 2022-11-25 Accepted: 2022-12-11 Published online: 2022-12-28

The carbapenem-resistant strains of Pseudomonas aeruginosa are considered as the dangerous pathogens of critical priority. Deciphering the mechanisms underlying the development of carbopenem resistance is an urgent challenge faced by modern medical science. The study was aimed to describe the diversity and fixation of mutations associated with the development of carbapenem resistance during the P. aeruginosa adaptation to the increasing meropenem concentrations. The objects of the study were P. aeruginosa isolates obtained by growing the ATCC 27853 P. aeruginosa reference strain exposed to increasing concentrations of meropenem. The isolates were tested for meropenem susceptibility using E-tests (Epsilometer tests) and by the agar dilution method. Genomes of the isolates were sequenced in the MGISEQ-2000 whole-genome sequencer. The findings show that in experimental settings P. aeruginosa develops high meropenem resistance very quickly (in 6 days). Evolution of resistance is associated with cloning involving the emergence of multiple clones with various genotypes. Mutagenesis that involves 11 genes, including oprD, pbuE, nalD, nalC, spoT, mlaA, mexD, mexR, oprM, mraY, pbp3, provides the basis for cloning. Regardless of the levels of their meropenem resistance, some of the emerging clones do not progressively develop and are replaced by more successful clones.