Sensibility assay for topical agents. A new method.

Abstract

We present a new laboratory method to test the sensibility of clinically isolated strains to topical agents. It is a method of dilution of the whole cream in a solid medium. The cream is weighted, suspended in sterile water, and maintained at 45 degrees C. Then a volume of that suspension is added to the agar, maintained at 45 degrees C also. The mixture is agitated and plated. Afterwards 25 strains are inoculated by a Multinoculator (Cetin, Bs. As., Argentina). After incubation (18 hours at 37 degrees C), the results are obtained by observing the presence or absence of bacterial development. The minimal inhibitory concentration is calculated as the lowest concentration that inhibited growth. It is a simple, economical, and reproducible method.