Antioxidant and antibacterial study of 10 flavonoids revealed rutin as a potential antibiofilm agent in Klebsiella pneumoniae strains isolated from hospitalized patients

The emergence of multidrug resistance (MDR) and extensive drug (XDR) in Klebsiella pneumoniae strains has posed great threats to conventional antibiotics. Previous studies have shown that plant-derived flavonoids inhibitory functions against pathogens. However, K. pneumoniae, the antibacterial activity different growth biofilm formation remains a mystery. aim present study was evaluate antioxidant abilities flavonoids, screen active ingredients identify their effects on formation. In total, 10 representing 4 major categories were screened used this study. capacity each flavonoid evaluated through DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Rutin showed highest level free radical scavenging capacity, followed by kaempferol, luteolin, quercetin, apigenin, hesperidin, sinensetin, naringenin, naringin 3,5,6,7,8,3′,4′-heptamethoxyflavone. rutin bacterial also compared. lowest MICs found ATCC700603 (1024 μg/mL) E. coli ATCC25922 (512 μg/mL). MBICs not found. strong ability both curve production. expression profiles 15 biofilm-related genes analyzed cells with without treatment. luxS gene wabG downregulated significantly Correlation analysis mrkA positively correlated biomass accumulation. Our indicated production is several rather than one. MrkA as potential agent inhibit