Evaluation of Dubos' Solid Medium Containing Penicillin in the Isolation of Tubercle Bacilli.

Abstract

Of 300 clinical specimens 134 were positive for tubercle bacilli on Dubos'' solid oleic acid-albumin medium containing 100 U./cc. of penicillin, and 120 were positive on a standard egg-potato medium. Without the presence of penicillin to restrain contaminants, only 91 cultures were positive on the Dubos medium. The Dubos medium was also considered satisfacotry because of the ease with which growth could be observed on the transparent agar, and because of the characteristic cord-like appearance of virulent tubercle bacilli, which apparently distinguishes them from avirulent tubercle bacilli, and from other organisms.