Abstract
Carbapenemase-producing Acinetobacter baumannii (CP-Ab) is a critical priority pathogen. Between October 2019 and September 2020, a multicentre study was conducted at four Ethiopian hospitals: Tikur Anbessa and Yekatit (central), Hawassa (southern), and Dessie (northern). A total of 1416 sepsis patients were enrolled, and blood cultures were performed. Acinetobacter isolates were confirmed using MALDI-TOF and tested for carbapenem susceptibility. All Acinetobacter isolates were subjected to whole-genome sequencing. Selected isolates underwent nanopore sequencing through Plasmidsaurus. Forty-five Acinetobacter isolates were identified, mostly A. baumannii (n = 38), with a few other species (n = 7). Among the 38 A. baumannii isolates, 18 carried bla(NDM−1) and either bla(OXA−23) or bla(OXA−58) carbapenemase genes concurrently. bla(OXA−58) and bla(NDM−1) were co-located on plasmids of sizes 80 kb to 113 kb. bla(OXA−66) (n = 13) and bla(OXA−69) (n = 12) were frequently identified chromosomally encoded carbapenemase genes. Several STs of A. baumannii were identified, with ST2 (n = 14) and ST1 (n = 13) being frequent. One A. nosocomialis carried bla(NDM−1) and bla(OXA−58) simultaneously. Several other genes were identified that confer resistance to aminoglycosides (n = 37), phenicol (n = 19), trimethoprim (n = 16), macrolides (n = 25), quinolones (n = 10), tetracyclines (n = 22), sulphonamides (n = 36), and disinfectants (n = 23). The high prevalence of carbapenemase-producing A. baumannii and other Acinetobacter species underscores the need for nationwide antibiotic stewardship. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-44498-1.