First genomic report of epidemic super-lineage, clade 2.5.6 Acinetobacter baumannii from hospital environmental surfaces in Bangladesh

The World Health Organization classifies Acinetobacter baumannii as a critical-priority carbapenem-resistant nosocomial pathogen. Hospitals are underrecognized reservoirs of multidrug-resistant (MDR) bacteria, yet Bangladesh has limited environmental genomic surveillance, especially of International Clone 2 (IC2). A. baumannii was isolated and genomically characterized from 95 environment samples collected at two district-level hospitals in Jashore, Bangladesh. Biochemical characterization identified 38 isolates as Acinetobacter spp. (40%), of which 86% were moderate-to-strong biofilm formers and universally carbapenem-resistant. International Clone 2 (IC2) was identified by multiplex PCR using three isolates. Whole-genome sequencing was performed on two representative isolates, 2GbA2_JUST (pneumonia ward bed, XDR) and A_38_JUST (toilet dam water, MDR) and MLST analysis grouped them as ST2. Capybara SNP barcode categorization positively identified both samples as Epidemic Super-Lineage Clade 2.5.6. Resistome profiling found 28 ARGs per isolate, including OXA-66, plasmid-borne OXA-23, armA, ADC-73, and three full RND efflux systems. Virulome analysis found 17 functional virulence categories. Analysis of 37 A. baumannii genomes revealed an open pangenome (γ = 0.301). To our knowledge, this study provides the first genomic characterization of Epidemic Super Lineage (ESL) Clade 2.5.6 Acinetobacter baumannii recovered from hospital environmental surfaces in Bangladesh. Competing interests The author(s) declare no competing interests. Generative AI and AI-assisted technologies in the writing process During the preparation of this work the author(s) used Gemini v3.0/Paraphrasing service to improve writing quality. Af... [1023 chars]