On the Antibiotic Activity of Mycobacteria and Nocardia : Preliminary Report on a Tuberculostatic Substance contained in Bacteria Cell

Abstract

The antibiotic activity of 297 strains of mycobacteria and 52 strains of acidfast nocardia were investigated. It was found that the antibiotic activity of mycobacteria aud acid-fast norcardia were mainly against tubercle bacilli but not against Escherichia coli or Micrococcus pyogenes var. aureus. Their antifungal activity were also not negligible. No growth of avian tubercle bacilli was in many cases observed on the plate where the active strains had been grown. Almost all the strains active against avian tubercle bacilli had somewhat similar colony appearance to that of tubercle bacilli. The potency of the fermented broth of the active strains was not so high and the active substance of which minimal inhibitory concentration against avian tubercle bacilli was 0.05 γ per ml existed mainly in the bacterial cell bodies. The production of the active substance of mycobacteria seemed to decrease rapidly.