PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF CARBAPENEMASES AND BIOFILM FORMATION IN CLINICALLY ISOLATED CARBAPENEM-RESISTANT KLEBSIELLA PNEUMONIAE

Abstract

Background: Carbapenem resistance and biofilm formation are important characteristics of Klebsiella pneumoniae that contribute to treatment challenges and bacterial persistence. Objective: In response to this growing threat, the present work investigated carbapenemase production among clinical K. pneumoniae isolates and evaluated its potential relationship with biofilm formation. Methodology: Twenty clinical K. pneumoniae isolates were evaluated for antimicrobial susceptibility using the disc diffusion technique. Carbapenemase and metallo-β-lactamase production were phenotypically evaluated using mCIM and eCIM, respectively. Biofilm production was quantitatively assessed using the crystal violet microtiter plate assay. PCR was performed to detect selected carbapenemase-associated genes (blaNDM, blaKPC, blaVIM, blaIMP, and blaOXA-48) and biofilm- related genes (fimH, mrkD, and sugE). Results: All isolates exhibited multidrug-resistant CRKP profiles. Carbapenemase activity was demonstrated in 85% of isolates, while MBL phenotype was observed in 40%. Biofilm production was detected in 70% of isolates, with weak biofilm formation being the predominant phenotype. The blaNDM, blaOXA-48, blaVIM, and blaKPC genes were detected in 70%, 50%, 30%, and 25% of isolates, respectively, whereas blaIMP was not detected. Although biofilm formation was prevalent, no statistically significant association was identified between biofilm phenotype and carbapenemase production, carbapenemase type, or individual carbapenemase genes. Conclusion: The findings demonstrate a high burden of carbapenemase-associated resistance among the investigated CRKP isolates. Despite the absence of statistically significant associations, the observed variations in biofilm phenotype across different carbapenemase types and genes suggest the need for further investigation into the multifaceted processes that control biofilm development in CRKP isolates.