Emergence and Spread of Epidemic Multidrug-Resistant Pseudomonas aeruginosa

Tohru Miyoshi-Akiyama1, Tatsuya Tada2, Norio Ohmagari3

  • 1Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.

Insights

Multidrug-resistant Pseudomonas aeruginosa (MDR P. aeruginosa) spread is driven by clonal expansion. Whole genome sequencing revealed specific genetic traits in the predominant ST235 lineage, explaining its global dominance as a nosocomial pathogen.

Area of Science:

  • Microbiology
  • Genomics
  • Epidemiology

Background:

  • Pseudomonas aeruginosa is a major global nosocomial pathogen.
  • The emergence and spread of multidrug-resistant (MDR) strains pose a critical challenge.
  • Understanding the drivers of MDR P. aeruginosa population structure is essential.

Purpose of the Study:

  • To define the population structure of P. aeruginosa clinical isolates using whole genome sequencing (WGS).
  • To identify key features contributing to the emergence and spread of MDR P. aeruginosa, particularly sequence type 235 (ST235).

Main Methods:

  • Whole genome sequencing (WGS) of 185 P. aeruginosa clinical isolates.
  • Phylogenetic analysis to determine population structure and subclades.
  • Analysis of drug resistance genes, genetic background, and specific systems (Type IV secretion, CRISPR/CAS).

Main Results:

  • 136 of 185 isolates belonged to the globally common ST235.
  • Phylogenetic analysis revealed seven subclades within ST235, each with distinct drug resistance genes and geographic confinement.
  • ST235 MDR P. aeruginosa exhibited a higher substitution rate and commonly possessed a Type IV secretion system, while lacking CRISPR/CAS.
  • Clonal expansion following antibiotic exposure appears to drive population structure.

Conclusions:

  • The findings elucidate the mechanisms behind the emergence and spread of ST235 as a predominant MDR P. aeruginosa lineage.
  • Specific genetic characteristics and clonal expansion contribute to the global success of this nosocomial pathogen.