Acinetobacter baumannii Global Clone-Specific Resistomes Explored in Clinical Isolates Recovered from Egypt

Area of Science:

• Medical Microbiology
• Genomic Epidemiology
• Antimicrobial Resistance

Background:

• Acinetobacter baumannii is a critical opportunistic pathogen known for rapid acquisition of antibiotic resistance.
• Understanding the genomic basis of drug resistance in clinical isolates is crucial for effective treatment strategies.

Purpose of the Study:

• To investigate the genomic epidemiology and characterize the resistome of multidrug-resistant Acinetobacter baumannii clinical isolates.
• To identify key resistance genes and genetic elements contributing to antimicrobial resistance in specific global clone lineages.

Main Methods:

• Whole-genome sequencing of 46 Acinetobacter baumannii clinical isolates.
• Antimicrobial susceptibility testing using broth microdilution.
• In silico multi-locus sequence typing and resistome analysis.

Main Results:

• High rates of multi-, extensive-, and pan-drug resistance were observed, with limited susceptibility to colistin, amikacin, and trimethoprim/sulfamethoxazole.
• The blaOXA-23 carbapenem resistance gene was the most prevalent, found in 69.6% of isolates across all identified global clones.
• Novel sequence types were identified, and specific resistance genes like blaOXA-23 and sul1 were distributed across all global clones.

Conclusions:

• The study highlights the significant contribution of five global clones to Acinetobacter baumannii infections in Egypt.
• Comprehensive analysis revealed GC-specific resistomes and the widespread dissemination of blaOXA-23, emphasizing the urgent need for antimicrobial stewardship.