Genotypic and Phenotypic Detection of Carbapenemase Genes in Clinical and Environmental Isolates of Klebsiella pneumoniae ST23

Background and Objectives: The global rise of multidrug-resistant bacteria poses a major healthcare challenge. Carbapenemase-producing Klebsiella pneumoniae, especially ST23, has emerged as a significant hospital-acquired pathogen. This study aimed to determine the prevalence, antimicrobial resistance profiles, and genetic features of carbapenemase-producing K. pneumoniae ST23 isolated from patients and hospital environments in a tertiary care hospital.
Materials and Methods: Over nine months, 150 samples were collected—75 clinical (blood, urine, wound swabs, respiratory secretions) and 75 environmental (beds, ventilators, door handles, and surfaces). Standard microbiological techniques and the VITEK 2 Compact system were used for identification. Antimicrobial susceptibility testing assessed carbapenem resistance. Multiplex PCR was performed on phenotypically resistant isolates to detect bla_KPC, bla_NDM, bla_OXA-48, bla_VIM, and bla_IMP genes. MLST confirmed ST23 strains.
Results: Of 150 samples, 68 isolates were K. pneumoniae, with 43 (28.6%) carbapenemase producers. Most (60.5%) originated from clinical samples, mainly urine and wound swabs. VITEK analysis showed imipenem and meropenem resistance rates above 75%. PCR revealed gene prevalence: bla_NDM (58.1%), bla_OXA-48 (46.5%), bla_KPC (30.2%), bla_VIM (27.9%), and bla_IMP (23.2%). Co-expression of multiple genes occurred in 38% of isolates. All genotypically positive isolates were confirmed as ST23 by MLST.
Discussion: The frequent detection of bla_NDM and bla_OXA-48, especially in clinical and environmental ST23 strains, underscores hospitals as key reservoirs for resistance. These findings highlight the urgent need for surveillance, strict hygiene, and molecular diagnostics to control hospital-acquired infections and limit community spread.