The sensitivity of Porphyromonas gingivalis and Fusobacterium nucleatum todifferent (pseudo)halide-peroxidase combinations compared with mutans streptococci

Previous studies have shown that the peroxidase system with iodide is parti cularly effective against Actinobacillus actinomycetemcomitans. In the pres ent study, the effects of iodide, chloride and thiocyanate in combinations with lactoperoxidase (LP) and myeloperoxidase (MP) on the viability of Porp hyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and S. rattus were analysed. Bacteria were incubated in buffer solution containing peroxidase, substrate(s) and H2O2 (all in oral physiological concentration s), and plated after 0, 0.5 and 1 h. The oxidation product of iodide was th e most bactericidal against all the bacteria tested. The effect was signifi cantly weaker on mutans streptococci. Physiological concentrations of thioc yanate abolished the effects of LP-H2O2-iodide and MP-H2O2-iodide/chloride combinations. Thiocyanate-peroxidase systems have already been used in oral hygiene products. The incorporation of iodide into these products could ma ke them much more potent against periodontal pathogens, and also help to pr event transmission of these pathogens from person to person via saliva.