Abstract
We previously pointed out 1 the constant occurrence of Bacterium melaninogenicum 2 in the normal mouth and on the external genitalia, and its abundance in connection with various pathologic processes.
Since then, our experience and that of others has amply confirmed the very frequent association of this bacterium with infections of various types, and while there is no satisfactory evidence that the organism is by itself invasive, it is one of the most prominent concomitant organisms in pyorrhea, lung abscess, sub-acute puerperal fever, and similar mixed infections.
Workers have not yet succeeded in maintaining the organism in pure culture, and therefore its systematic description and identification have not been attempted. The organism will develop readily for a time in symbiosis with other organisms (such as Strep. viridans), but its ultimate isolation from such mixtures is no easier than from the primary cultures, and it is soon lost.
Recognizing that the formation of pigment by an organism is associated with senescence, Dr. Bronfenbrenner suggested that the almost constant failure to secure pure growth in transfers from pigmented colonies is probably due to loss of viability of the organisms. It was found that this assumption is correct, and that pure cultures can be secured and maintained if transfers are made very frequently from colonies before they develop much pigment. The original material is streaked directly upon plates of freshly made hormone blood agar (pH 7.4) and the plates are incubated for about 4 days in an anaerobic jar. Single colonies which are just beginning to show a brownish color are then fished to warmed plates of the same medium. Thereafter the pure growths must be transplanted at short intervals (48-72 hours) until they become adjusted to artificial conditions.
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