Highly clonal carbapenem-resistant Acinetobacter baumannii isolates from a Peruvian hospital

Area of Science:

• Clinical microbiology
• Genomics
• Antimicrobial resistance

Background:

• Acinetobacter baumannii is a critical pathogen causing severe hospital infections.
• High levels of antimicrobial resistance, including to carbapenems, are a major clinical concern.
• Limited data exist on the genetic background and spread of resistant strains in Latin America.

Purpose of the Study:

• To characterize extensively drug-resistant Acinetobacter baumannii from a Peruvian hospital during the COVID-19 pandemic.
• To investigate the genetic relatedness and resistance mechanisms of these isolates.
• To provide local genomic data for global antimicrobial resistance surveillance.

Main Methods:

• Antimicrobial susceptibility testing (VITEK-2).
• Polymerase chain reaction (PCR) for carbapenemase genes.
• Pulsed-field gel electrophoresis (PFGE).
• Whole-genome sequencing (WGS).

Main Results:

• All 40 Acinetobacter baumannii isolates were extensively drug-resistant.
• blaOXA-24-like and blaOXA-23-like genes were detected.
• PFGE revealed three distinct pulsotypes, with one predominant clone.
• WGS identified international clone II (ST2 and ST2724) with multiple resistance genes and a genomic resistance island.

Conclusions:

• A predominant, highly resistant clone of Acinetobacter baumannii (ST2, international clone II) is circulating in Peru.
• These findings underscore the silent spread of high-risk clones in low-resource settings.
• Strengthening molecular monitoring of hospital-associated pathogens is crucial, especially in low- and middle-income countries.