Diversity of Sequence Types and Impact of Fitness Cost among Carbapenem-Resistant Acinetobacter baumannii Isolates from Tripoli, Libya

We investigated the molecular epidemiology of 21 carbapenem-resistant Acinetobacter baumannii isolates from Libya and assessed their relative fitness. Core genome multilocus sequence typing (MLST) revealed five interhospital transmission clusters. Three clusters were associated with the international clones (IC) IC1, IC2, and IC7. Carbapenem-resistance was associated with bla(OXA-23), bla(GES-11), or bla(NDM-1). Compared to that of A. baumannii DSM 30008, the doubling time was similar over 10 h, but after 16 h, half the isolates grew to higher densities, suggesting a fitness advantage.

Automated summary

The molecular epidemiology of carbapenem-resistant Acinetobacter baumannii isolates from Libya was investigated, revealing interhospital transmission clusters associated with international clones IC1, IC2, and IC7. Carbapenem resistance was linked to specific genes, with some isolates showing a fitness advantage compared to a reference strain.