THE INDUCED DEVELOPMENT OF NON-ACID-FAST FORMS OF BACILLUS TUBERCULOSIS AND OTHER MYCO-BACTERIA.
Six strains of mycobacteria,-three human strains, Saranac H-37, T. S., and No. 90, a bovine strain, B-1, a smegma strain, No. 74, and a Saranac strain of B. phlei,-have been made to grow as non-acid-fast organisms by the addition to the culture media of a filtered extract of the chromogenic H-37 strain of B. tuberculosis. The action of the extract produced acceleration of growth of the treated culture, followed by macroscopic and microscopic changes, and differentiation into non-acid-fast forms. The bacterial forms grown from these treated cultures were pleomorphic, usually consisting of cocci and small rods; but branching forms and spore-like bodies also developed. The sterility of the extract causing the changes was demonstrated by frequent control inoculations on various media, including Kendall's K medium; and autoclaved extracts had the same effects as non-autoclaved. After transfer to media suitable for acid growths four of the strains reverted not only to acid-fastness but to their original cultural characteristics, providing evidence that the non-acid-fast forms were specific for the strain.
H. K. Cushing Laboratory of Experimental Medicine in the Department of Medicine of Western Reserve University and the Medical Service of Lakeside Hospital, Cleveland.
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Miller