Yanagawa
, R. (National Institute of Animal Health, Kodaira, Tokyo, Japan),
T. Hiramune, and J. Fujita
. Effects of carbon dioxide on the colonial growth of pathogenic leptospirae. J. Bacteriol.
85:
875–880. 1963.—The growth of colonies of pathogenic leptospirae was examined in air of various CO
2
concentrations, ranging from air from which CO
2
was absorbed to air with 20% CO
2
added, and was compared with the growth of other microorganisms of the genera
Mycoplasma, Brucella, Vibrio, Erysipelothrix, Staphylococcus, Micrococcus, Sarcina, Klebsiella, Salmonella, Escherichia
, and
Bacillus
. The colonial growth of the 24 strains of pathogenic leptospirae examined was similar to that of other organisms in that the growth was negative in air from which naturally contained CO
2
had been absorbed, the growth tended to be inhibited in 5 to 20% CO
2
in proportion to the CO
2
concentration, and good colonial growth of leptospirae was obtained in a relatively narrow range of CO
2
concentration (from the normal amount in air to around 1%). The growth of some leptospirae was accelerated in 1% CO
2
, but not that of the strains of
Leptospira icterohaemorrhagiae
, which required a lower range of CO
2
, and of
L. canicola
. The CO
2
requirement of pathogenic leptospirae was similar, to some extent, to that of
Mycoplasma mycoides
, but was not so high as that of
Brucella abortus
. Incorporation of C
14
O
2
was demonstrated in leptospirae.
