Epidemiology, Phenotypic and Genotypic Characterization of Carbapenem-Resistant Gram-Negative Bacteria from a Libyan Hospital

Antimicrobial resistance, particularly resistance to carbapenems, has become one of the major threats to public health. Seventy-two isolates were collected from patients and hospital environment of Ibn Sina Hospital, Sirte, Libya. Antibiotic susceptibility tests, using the disc diffusion method and E-Test strips, were performed to select carbapenem-resistant strains. The colistin (CT) resistance was also tested by determining the minimum inhibitory concentration (MIC). RT-PCR was conducted to identify the presence of carbapenemase encoding genes and plasmid-mediated mcr CT resistance genes. Standard PCR was performed for positive RT-PCR and the chromosome-mediated CT resistance genes ( ). Gram-negative bacteria showed a low susceptibility to carbapenems. Molecular investigations indicated that the metallo-β-lactamase New Delhi metallo-beta-lactamases-1 was the most prevalent ( = 13), followed by Verona integron-encoded metallo-beta-lactamase (VIM) enzyme (VIM-2 [ = 6], VIM-1 [ = 1], and VIM-4 [ = 1]) that mainly detected among . The oxacillinase enzyme OXA-23 was detected among six , and OXA-48 was detected among one and three in which one coharbored the carbapenemase enzyme and showed resistance to CT (MIC = 64 μg/mL) by modification in genes. In this study, we report for the first time the emergence of carrying the gene and belonging to sequence type773 in Libya. Our study reported also for the first time CT resistance by mutation in the gene among Enterobacteriaceae isolates in Libya.