The lactoperoxidase-thiocyanate-hydrogen peroxide antibacterium system.

Lactoperoxidase present in various secretions oxidizes thiocyanate (SCN-) in the presence of H2O2 to an unstable oxidation product--hypothiocyanite (OSCN-), which is bactericidal for enteric pathogens including multiple antibiotic resistant strains of E. coli. The system damages the inner membrane causing leakage and cessation of uptake of nutrient, leading eventually to death of the organisms and lysis. The possible involvement of O2- and 1O2 is discussed.