MOLECULAR CHARACTERIZATION OF ANTIBIOTIC RESISTANCE GENES IN MULTIDRUG-RESISTANT KLEBSIELLA PNEUMONIAE CLINICAL ISOLATES

The global rise in multidrug-resistant (MDR) Klebsiella pneumoniae presents a significant threat to public health,particularly in clinical environments where treatment options are becoming increasingly limited. K. pneumoniae,a Gram-negative opportunistic pathogen, is frequently implicated in hospital-acquired infections such aspneumonia, bloodstream infections, urinary tract infections, and surgical site infections. The growing incidenceof strains resistant to multiple classes of antibiotics, including carbapenems, cephalosporins, and aminoglycosides,necessitates molecular investigations to understand the genetic underpinnings of resistance. This study aimed tocharacterize the distribution and diversity of antibiotic resistance genes (ARGs) in MDR K. pneumoniae clinicalisolates obtained from tertiary healthcare centers. Bacterial isolates were identified phenotypically, followed byantimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method. Genomic DNA was extracted,and multiplex PCR assays were performed to detect key ARGs, including those encoding extended-spectrum βlactamases (ESBLs), carbapenemases (e.g., bla_KPC, bla_NDM, bla_OXA), and plasmid-mediated quinoloneresistance (PMQR) determinants. Sequencing of representative amplicons was conducted to confirm gene identityand assess mutations. Results revealed a high prevalence of bla_CTX-M, bla_SHV, and bla_TEM genes, withnotable co-occurrence of bla_NDM-1 and bla_OXA-48 in several isolates. Plasmid profiling and conjugationassays further indicated the horizontal gene transfer potential among enterobacterial species. This study highlightsthe alarming genetic diversity and dissemination capacity of resistance determinants in K. pneumoniae,emphasizing the need for routine molecular surveillance, stringent infection control practices, and informedantimicrobial stewardship strategies. Targeted molecular diagnostics and rapid genotyping of resistance genescould significantly aid in mitigating the spread of MDR pathogens within hospital networks.