On the Isolation of a Strain of Penicillia which Possesses a Bacteriostatic Action against Gram-Positive Bacteria and a Property to Produce Penicillin

The fact that a substance which resembled very closely penicillin could be obtained from the culture filtrate of a strain of penicillia isolated by the author was revealed by the present paper. Thus it was shown that there was considerable evidence of biological similarity between penicillin and the isolated antibiotic substance. 1) A strain of penicillia which produced in cultures a powerful anti-bacterial substance against Gram-positive bacteria was isolated from a contaminating blood plate in the laboratory. 2) The antibacterial power of the cultures reached its maximum in about 11 days at 20°-25°C. and after 12 days diminished, until it had almost disappeared in 27 days. 3) The best one of all culture media used for the production of the antibacterial substance was a Czapek medium with 1% Katayama's peptone (initial pH. was 7.0). In reference to the Czapek medium, kinds of peptones used had a great effect upon the potency of antibiotic sub-stances, but not upon the growth and the spore formation of this fungus. 4) The culture filtrate inhibited the growth, in particular, of sta-phylococci, streptococci, Bac. anthracis, Corynebact. diphtheriae, gonococci, meningococci, and pneumococci, namely Gram-positive bacteria, but not the growth of B. coli, Salmonella typhi, S. paratyphi A, S. paratyphi B, S. enteritidis B. dysenteriae, Proteus vulgaris, P. pyocyanea, or Vibrio cholerae, namely Gram-negative bacteria. 5) The rate of killing of staphylococci by the culture filtrate was very weak. It was thought, therefore, that its action was bacteriostatic rather than bactericidal. 6) The antibacterial titre of small bright yellow drops which were collected on the surface of the fungus was higher than the titre of the culture filtrate. 7) Passage through the Berkefeld filter diminished the antibacterial power, but not through the Seitz filter or filter paper. 8) At pH 2.0 the culture filtrate lost almost all powers after 1 day at the refrigerator temperature, but if its reaction was kept from pH 5.0 to 7.0, it could be preserved almost constantly after 14 days. 9) The active agent of the culture filtrate was thermostable, if it was kept from pH 5.0 to pH 7.0, but boiling at pH 2.0 for 30-60 minutes re-duced the power considerably. 10) The culture filtrate was able to be concentrated to one fifteenth of its volume by means of vacuum distillation at about 35°C. without di-minishing of the antibiotic titre. 11) The culture filtrate was non-toxic to animals in enormou