Virulence and resistance mechanisms of carbapenemase-producing Klebsiella pneumoniae: Insights into biofilm formation and cytotoxicity

Abstract

Carbapenem drugs have the potential to prevent disease caused by both gram-positive and gram-negative bacteria. This beta-lactam family drug prevents the cell wall biosynthesis of pathogens, but the pathogen hydrolyzes it using the enzymes carbapenemase and beta-lactamase. In this study, we analyzed the biochemical characterization, biofilm formation, hemolytic activity, and biofilm-forming ability of carbapenemase-producing Klebsiella pneumoniae under various conditions. The Gram-negative rod-shaped bacteria showed positive results in the methyl red and citrate tests, and lactose fermentation in sugar tests; other biochemical characteristics identified the isolate as Klebsiella pneumoniae. The well developed biofilm has developed after five days (120 hours) of incubation at ambient temperature (35 C^°). The hemolytic activity has shown 100 % cell lysis at 1 mg/mL (1000μg/mL) which retained the toxicity after sterilization indicates the virulence of pathogen. The viability of pathogens under thermal stress has revealed substantial survival at 100°C. The growth declined at 150°C, and the cells death at 200°C and above. Antibiofilm assay using carbapenemase at a concentration of 1000 µg/mL resulted in the reduction of cell density, and the biofilm has a layer of live active cells marked by acridine orange. It showed the stress adaptation, higher level of tolerance, and cytotoxicity of the carbapenemase-producing pathogen Klebsiella pneumoniae. Overall, it can cause difficult challenges in medical and clinical practices and treatments.