Genomic Analysis of Virulence Gene Islands in Carbapenem-Resistant Acinetobacter baumannii Isolates from Burns Units in Northern Nigeria

Carbapenem-resistant Acinetobacter baumannii (CRAB) is among the most clinically formidable nosocomial pathogens, with burns units representing high-risk niches for CRAB acquisition due to loss of skin barrier function and prolonged hospitalization. Genomic analysis of virulence islands and resistance gene contexts in CRAB isolates is essential for understanding pathogenesis and epidemiology in Nigerian tertiary settings. This study performed comparative genomic analysis of CRAB isolates from burns units at Ahmadu Bello University Teaching Hospital (ABUTH) Zaria and Usmanu Danfodiyo University Teaching Hospital (UDUTH) Sokoto, Northwest Nigeria. Twenty-three CRAB isolates were whole-genome sequenced using Illumina short-read technology. Draft genomes were assembled using SPAdes and annotated with Prokka. Resistance gene identification used ABRicate against multiple databases. Virulence gene islands (VGIs) were identified using IslandViewer 4. Core genome MLST based on the Pasteur scheme was applied for clonal lineage assignment. International Clone II (IC2) was the dominant lineage (78%), associated with OXA-23-mediated carbapenem resistance in all IC2 isolates. VGI analysis revealed genomic islands carrying bauA (siderophore), ompA (outer membrane protein adhesin), and bap (biofilm-associated protein) genes. Two isolates shared identical VGI structure and MLST type across both hospitals, suggesting inter-hospital clonal dissemination. These genomic insights define virulence-resistance co-evolution patterns in CRAB lineages circulating in Northwest Nigerian burns units. Keywords: Acinetobacter baumannii, virulence gene islands, carbapenem resistance, burns unit, Northwest Nigeria.