Polyphenolic Secondary Metabolites Synergize the Activity of Commercial Antibiotics against Clinical Isolates of β-Lactamase-producing Klebsiella pneumoniae.

Emergence of worldwide antimicrobial resistance prompted us to study the resistance modifying potential of plant-derived dietary polyphenols, mainly caffeic acid, ellagic acid, epigallocatechin-3-gallate (EGCG) and quercetin. These compounds were studied in logical combination with clinically significant antibiotics (ciprofloxacin/gentamicin/tetracycline) against Klebsiella pneumoniae, after conducting phenotypic screening of a large number of clinical isolates and selecting the relevant strains possessing extended-spectrum β-lactamase (ESBL) and K. pneumoniae carbapenemase (KPC)-type carbapenemase enzymes only.

Antimicrobial activity of pomegranate fruit constituents against drug-resistant Mycobacterium tuberculosis and β-lactamase producing Klebsiella pneumoniae.

Context: The global surge in multi-drug resistant bacteria and the imminence of tuberculosis pandemic necessitate alternative therapeutic approaches to augment the existing medications. Pomegranate, the fruit of Punica granatum Linn. (Punicaceae), widely recognized for potency against a broad spectrum of bacterial pathogens, deserves further investigation in this respect.

Antitubercular and antibacterial activity of quinonoid natural products against multi-drug resistant clinical isolates.

Multi-drug resistant Mycobacterium tuberculosis and other bacterial pathogens represent a major threat to human health. In view of the critical need to augment the current drug regime, we have investigated therapeutic potential of five quinonoids, viz. emodin, diospyrin, plumbagin, menadione and thymoquinone, derived from natural products.

Pomegranate pericarp extract enhances the antibacterial activity of ciprofloxacin against extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) producing Gram-negative bacilli.

A methanolic extract of Punica granatum (pomegranate) fruit pericarp (PGME) was tested in combination with ciprofloxacin against extended-spectrum β-lactamase (ESBL) producing Escherichia coli, Klebsiella pneumoniae, and metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa, which were screened for their resistance profile against fluoroquinolone antibiotics. The minimum inhibitory concentrations (MIC) of ciprofloxacin and PGME, alone, were determined, and synergy of ciprofloxacin-PGME combinations evaluated by checkerboard assay and fractional inhibitory concentration (FIC). Nineteen out of forty-nine strains exhibited synergy with ciprofloxacin (FIC of 0.