Polyclonal multidrug-resistant Acinetobacter baumannii circulation in eight wards of the Tripoli University Hospital, Libya.

BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen infecting immunocompromised patients, including the pediatric population. Treatment options for severe infections are challenged by the dissemination of carbapenem-resistant A. baumannii (CRAB) mostly belonging to eleven international clones (IC1-11). OBJECTIVES: Unlike neighboring countries, characterization of CRAB from Libya is rare. In this study, 38 CRAB isolates collected during 2020-2021 from patients treated in the Tripoli University Hospital (TUH) were characterized by whole-genome sequencing for their antibiotic resistance genes content, their genetic elements, and phylogenetic relationship to international isolates. RESULTS: The 38 isolates belonged to IC1, IC2, IC6, IC7 and IC11, this latter being the most frequently identified. All isolates harbored a blaOXA-23 gene, except IC6 isolates that carried a plasmid-located blaOXA-72. The blaNDM-1 gene occurred only in IC1 isolates. The phylogenetic analysis including publically available genomes evidenced a clustering according to the continent of origin. Isolates from TUH were phylogenetically close to isolates from North Africa or Middle East. Most of the CRAB (22/38, 58%) came from children, eight of whom died (36%). Circulation among adult and pediatric wards of the same clone was observed. CONCLUSION: At the TUH, improvement of hygiene measures are needed to lower the burden of CRAB. At the international level, surveillance of this pathogen remains crucial to prevent its further spread from endemic regions or from conflict zones where injuries are more frequent and hygiene conditions are more precarious.