Genomic and Phylogenomic Characterization of Carbapenem-resistant Pseudomonas aeruginosa 'High-risk' Clone...

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Carbapenem-resistant Pseudomonas aeruginosa (CRPA) poses a significant global health threat, often linked to high-risk clones.
• Limited data exists on the molecular epidemiology of CRPA in Chile, where it is a primary cause of ventilator-associated pneumonia.

Purpose of the Study:

• To conduct a comprehensive phylogenomic and molecular characterization of ST654 CRPA isolates from Chile.
• To analyze isolates collected between 2016 and 2022 to understand their evolutionary trajectory.

Main Methods:

• Whole-genome sequencing of 89 CRPA isolates collected between 2005 and 2022.
• In silico analysis, antibiotic susceptibility testing, and carbapenemase production assays on ST654 isolates.
• Phylogenetic analysis to determine clonal relationships and geographic clustering.

Main Results:

• The ST654 clone was the most predominant lineage (38.2%) among the analyzed CRPA isolates.
• Most ST654 isolates were KPC producers, clustering with strains from Argentina and the US; some VIM/NDM producers formed separate subclades.
• All ST654 isolates possessed the ExoS+ virulence factor and were associated with the O4 serotype, exhibiting a broad drug resistance profile.

Conclusions:

• This study provides the most extensive phylogenomic analysis of the CRPA ST654 clone to date.
• CRPA ST654 in Chile appears to be evolving distinctively, with a high prevalence of KPC producers and O4 serotype.
• Findings underscore the critical importance of continuous molecular surveillance for CRPA in Chile and globally.