Abstract
In the course of the study of smears from cases of bronchial asthma and routine cultures taken from cases of ringworm infection of the feet, numerous yeast-like organisms were encountered, especially those of the monilia group. Since fermentation reactions and serological tests proved to form a very important basis for the identification of the moniliae, as well as other yeasts, further studies have been made of these 2 characteristics.
Previous investigators, in the study of fermentation reactions, have made their observations on extract broth plus 1% fermentable sugars with Andrade's solution as an indicator, and Durham tubes for determination of gas. Because of the differences in the results of these authors, some method seemed necessary to investigate this test further. Pork infusion fermented broth (the carbohydrates in the meat infusion were removed by fermentation with B. coli before the peptone was added) was used with addition of the various carbohydrates. The medium was inoculated with monilia and incubated at 37°C. The pH of the inoculated media was followed every 2 or 3 days for 20 to 40 days by the colorimetric method described by Brown. 1 Eight or 10 drops of the uninoculated media gave distinctly positive reactions for sugar with Benedict's solution. Those cultures found to give a negative chemical test for sugar after a period of incubation were considered to have fermented the carbohydrates.
The hydrogen-ion concentration of the cultures of moniliae in 2% sugar broth over a period of 40 days showed a wide divergence in the amount of acidity produced in the fermenting process. Several strains, although showing little if any acidity, fermented the sugar as shown by its disappearance indicated by the negative Benedict's test. Taking the disappearance of the sugars as a basis for division, the moniliae fall into 3 groups:
A first group, M. albicans, M. Candida and M. psilosis, utilizes completely sucrose, dextrose, maltose, xylose, levulose and galactose, but does not attack inulin. A second group including M. parapsilosis and M. type 1 (Stovall), 2 utilizes 4 of the above sugars not fermenting maltose or inulin and rarely xylose. A third group includes M. krusei which does not utilize xylose, sucrose, maltose, galactose or inulin.
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