Hydrogen peroxide from l- amino acid oxidase of king cobra ( Ophiophagus hannah ) venom attenuates Pseudomonas biofilms

Because of the high incidence of Pseudomonas aeruginosa biofilms-related nosocomial infections, venoms from common Thai snakes were tested. Although venoms from king cobra ( Ophiophagus hannah ; OH) and green pit viper ( Trimeresurus albolabris ) showed the broadest antibacterial spectrum, OH venom demonstrated more profound anti-biofilm activities against P. aeruginosa . Additionally, purified l -amino acid oxidase from OH venom (OH-LAAO), using a three-step chromatography and protein identification, reduced biofilm mass as indicated by the downregulation of several genes, including the genes for biofilm synthesis ( algD and pslB ) and biofilm regulators ( algU , gacA , and siaD ). Moreover, OH-LAAO disrupted Pseudomonas -preformed biofilms via upregulation of several genes for biofilm dispersion ( nbdA , bdlA , and dipA ) and biofilm degradation ( endA and pslG ), resulting in a reduction of the biofilm biomass. Due to the antimicrobial effects and anti-biofilm activities (reduced production plus increased dispersion) neutralized by catalase, a hydrogen peroxide (H 2 O 2 )-degrading enzyme, the enhanced H 2 O 2 by OH venom might be one of the anti-biofilm mechanisms. Hence, OH-LAAO was proposed as a novel agent against Pseudomonas biofilms for either treatment or prevention. More studies are interesting.