In-silico and in-vitro evaluation of phytochemicals targeting outer membrane proteins OmpK35 and OmpK36 of MDR Klebsiella pneumonia

Multidrug-resistant (MDR) Klebsiella pneumoniae (Kp) presents a significant clinical threat due to its resistance to multiple antibiotics and its enhanced virulence. Key outer membrane porins, OmpK35 and OmpK36, contribute to this resistance by limiting antibiotic influx and supporting bacterial survival. This study aimed to identify and evaluate phytochemicals targeting these porins using an integrated in silico -in vitro approach. Over 100 phytocompounds were screened via molecular docking, revealing N-curcumin and myricetin as top candidates with binding affinities of -7.33 kcal/mol (OmpK35) and -7.58 kcal/mol (OmpK36), respectively. ADMET profiling supported their drug-likeness and safety. These compounds were further evaluated against reference and clinical Kp strains. Minimum bactericidal concentration (MBC) assays showed that both N-curcumin and myricetin achieved effective killing at 7.5 mg/mL. Biofilm inhibition rates ranged from 40-48%, comparable to standard gentamicin. Crystal violet staining and microscopy confirmed significant biofilm disruption. Additionally, oxygen consumption rate (OCR) assays revealed substantial reductions in metabolic activity. Myricetin led to OCR decreases of 0.40-, 0.52-, and 0.35-fold against MTCC-432, ATCC-35657, and CL-1 strains, respectively. Collectively, these findings highlight the dual antibacterial and antivirulence potential of N-curcumin and myricetin. Their ability to disrupt membrane protein function, inhibit biofilm formation, and impair bacterial respiration offers strong promise for their development as alternative therapeutics against MDR K. pneumoniae. This study supports the ongoing search for plant-derived compounds in the fight against resistant Gram-negative pathogens.