Effect of peroxidase-generated hypothiocyanite on the survival rate of Porphyromonas gingivalis NCTC 11834

The aim of this study was to investigate the effect of peroxidase-generated hypothiocyanite (OSCN-) in vitro on a type strain of Porphyromonas gingiva lis. We tested the susceptibility of P gingivalis strain NCTC 11834 to OSCN - using a lactoperoxidase system which oxidized 127 nmol cysteine/ml in 5 m in and 277 nmol/ml in 30 min. The bacterial survival rate was less than 1% after 5 min OSCN- exposure and was zero after 30 min. Under the same condit ions, the bacterial ATP content declined to 60% and 31% of the control leve l after 5 and 30 min respectively. No NADH-hypothiocyanite-oxidoreductase a ctivity could be detected in the bacterial lysate. Med Sci Res 27:667-669 ( C) 1999 Lippincott Williams & Wilkins.