FACTORS AFFECTING THE GROWTH OF MYCOBACTERIUM MARINUM

Abstract

The two strains of Mycobacterium marinum Aronson (Mycobacterium balnei Nordén) investigated were able to grow in a CO2-enriched atmosphere (5 and 10% CO2) in media in which they failed to grow or grew poorly when incubated in air. One strain grew better at 37 °C in cultures incubated in a CO2-enriched atmosphere than it did in cultures incubated at 30 °C either in air or in the CO2-enriched atmosphere. The growth of the second strain was stimulated markedly by CO2during incubation at 30 °C, and it was able to grow at 37 °C when supplied with additional CO2, although not as well as at 30 °C. Glutamic acid was the best single source of nitrogen for the growth of each strain, but one strain grew almost as well with asparagine. Oleic acid exerted inhibitory effects on the growth of each strain in a synthetic medium at 37 °C, whereas it produced a slight stimulatory effect on their growth at 30 °C. Tween 80 inhibited the growth of each strain in the synthetic medium at both 30 and 37 °C, but the degree of inhibition was greater at the higher temperature. Methods for obtaining uniform suspensions of the cells are described.