Distribution of carbapenemase-encoding genes (blaIMP, blaNDM, blaKPC, blaVIM and blaOXA-48) in carbapenem-resistant Klebsiella pneumoniae from Yemen

Background The emergence of carbapenem-resistant Klebsiella pneumoniae (CR-KP) represents a critical threat to global public health, severely limiting therapeutic options. Surveillance of these resistance determinants is essential to guide infection control and antimicrobial stewardship. This study aimed to identify the prevalence and distribution of specific carbapenemase-encoding genes ( bla KPC, bla NDM, bla IMP, bla VIM, and bla OXA-48) among clinical isolates of K. pneumoniae collected from various hospitals in Sana’a, Yemen. Methods A cross-sectional study was conducted in Sana’a, Yemen from October 2023 to December 2024. One hundred eighteen non-duplicate clinical isolates of Klebsiella pneumoniae (family Enterobacteriaceae) showing resistance to carbapenems (imipenem and meropenem) were recovered from wound, urine, sputum, blood and pus specimens collected at two private hospitals and the National Center of Public Health Laboratories. Antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion and colistin MIC by broth disk elution according to CLSI 2024. Carbapenemase production was screened by reduced carbapenem susceptibility and confirmed phenotypically with the combined imipenem/EDTA disk test for metallo-β-lactamases. Genotypic detection of bla KPC, bla NDM, bla IMP, bla VIM and bla OXA-48 was performed by real-time PCR using DNA extracted by boiling. Descriptive statistics were analyzed with SPSS v26. Results Among the 118 isolates, 84 (71.2%) were positive for at least one carbapenemase-encoding gene. The most predominant gene was bla OXA-48 (59.3%), followed by bla NDM (38.9%), bla VIM (33.9%), bla IMP (6.8%), and bla KPC (1.7%). Regarding specimen distribution, the highest positivity rate for these genes was found in pus (85.7%) and wound (77.8%) samples. Co-occurrence of multiple genes was frequent: 22 isolates (18.6%) harbored two genes, 24 (20.3%) harbored three genes, and 4 (3.4%) harbored four genes ( bla NDM, bla OXA-48, bla VIM, and either bla KPC or bla IMP). Antimicrobial susceptibility testing revealed 100% resistance to most β-lactams, including meropenem, imipenem, and ceftazidime. High resistance rates were also observed for ciprofloxacin (95.7%) and gentamicin (93.2%). Colistin remained the most effective agent, with a susceptibility rate of 97.5%. Conclusions Carbapenemase genes—particularly bla OXA-48, bla NDM and bla VIM—are widespread among carbapenem-resistant K. pneumoniae in Sana’a, Yemen, with frequent co-occurrence and extensive multidrug resistance. These findings underscore the urgent need for strengthened antimicrobial stewardship, routine molecular surveillance for carbapenemase genes, and rigorous infection-control measures to limit dissemination.