An investigation of the in vitro anti-bacterial activity of noxythiolin against 1,000 pathogenic bacterial isolates.

The susceptibility of 1,000 recent bacterial isolates to noxythiolin was determined by the disc susceptibility method. No Gram-positive strains were resistant to this method but 56 (5.6%) of Gram-negative strains gave zones of inhibition of 12 mm diameter or less. The minimum inhibitory concentration (MIC) of the latter were determined by the agar incorporation method. No strains had MIC values greater than 4096 mg/litre. Since concentrations of 50,000 mg/litre can be used for topical treatment, these organisms may be considered susceptible.

The antimicrobial properties of two commonly used antiseptic mouthwashes--Corsodyl and Oraldene.

The antimicrobial activities of the mouthwashes Corsodyl and Oraldene against common buccal organisms were essentially similar. The concentration of the active substance in the two mouthwashes was well in excess of the minimum inhibitory concentrations determined. Also a rapid lethal effect on the bacteria was found which, when combined with the previous property, may well account for the usefulness of these products in infectious conditions.