Abstract
Acinetobacter baumannii is an opportunistic pathogen causing various nosocomial infections. The aim of this study was to characterize the molecular support of carbapenem-resistant A. baumannii clinical isolates recovered from four hospitals in Tripoli, Libya. Bacterial isolates were identified and antibiotic susceptibility testing was per-formed using automated system. Carbapenem resistance determinants were studied phenotypically using two dif-ferent techniques: E-test; chromogenic culture media. Polymerase chain reaction (PCR) amplification was used to determine the presence of bla OXA23 and blaOXA51 genes among isolates. A total of 119 isolates were characterized, overall the resistance prevalence was extremely high for aminoglycosides (79-96.6%), fluoroquinolones (94-96%), cephalosporins (96.6-100%) and carbapenemes (93.2-100%), all isolates were susceptible to colistin. In addition, 97.5% of isolates were identified as multidrug resistance (MDR). Varying degree of phenotypic detection of car-bapenemes was determined; highest levels of carbapenemes were detected using chromogenic media (76.5%) com-pared with E-test (45.4 %). The carbapenem resistance-encoding genes detected were blaOXA23 (84%) and blaOXA51 (73.1%); the highest occurrence of blaOXA23 was demonstrated in Tripoli’s Central Hospital (5/5; 100%) then in Tripoli Medical Center (44/51; 86.27%). The co-occurrence of these genes was demonstrated in (75/119; 63%) showing dissemination of carbapenemes resistance MDR A. baumannii in hospitals. This study shows that the high prevalence of OXA-23 contribute to antibiotic resistance in … arabic 14 English 113