The Life Cycle of the Organism Causing Yeast Meningitis

Abstract

In studying the characteristics of several strains of the organism commonly called Torulk histolytica, some rather prominent structures were noted, the significance of which seems to have been overlooked in previous descriptions. The study of the nature of these bodies disclosed a sequence of changes in morphology which necessitates a revision of the classification of at least some of the members of this group. One of the strains studied was isolated on four occasions from the spinal fluid of a patient in the University of Iowa Hospitals. This man had symptoms indicative of lesions in the central nervous system for two years prior to admission in 1934. In January, 1936, his disturbance had neither progressed nor subsided. Another strain was recovered from the spinal fluid of a patient in the Minneapolis General Hospital in 1935. His illness, from onset to death in three months, was characterized by symptoms referable to the central nervous system and at necropsy these tissues exhibited typical lytic lesions. We are indebted to Dr. A. T. Henrici and Dr. N. H. Lufkin for the culture and history of this latter case. OBSERVATIONS Cultures of these two strains of organisms, when studied in the ordinary fashion, exhibited all of the described characteristics of Torula: reproduction by budding, no mycelium formed and glucose alone fermented, and without gas formation. However, 89

Lipid Production by a Soil Yeast

“…On the basis of preliminary observations, Wickerham (1944) concluded that it was unlikely that the yeast belonged in any of the present genera of sporogenous yeasts since none of the latter contain yeasts with its characteristics, such as mucoid cell material, colored ascospores, ascospores in excess of eight when cultured on certain media, and a strong tendency of old cells to shed their outer membranes. In some respects the yeast resembles a culture described as Debaryomyces hominis by Todd and Herrmann (1936). However, the structures which were described as spores of D. hominis are different from the spores of the soil yeast, but comparative studies might show more similarity between the two than is apparent from the description of Todd and Herrmann.…”

The Yeasts

“…Since spore-formation is often delayed, cultures should be examined repeatedly over a period of several weeks before they are to be labelled as asporogenous. Windisch (1938) reported spore formation in Torulopsis pulcherrima only after the agar cultures had dried considerably, and Todd and Herrmann (1936) had the same experience with Debaryomyces neoformans. Fuchs (1935) found that with old laboratory strains which had quit forming spores this character could be revived by growing them on wort agar, transferring the young growth to plaster blocks, then back to wort agar, and so on.…”

“…Diddens and Lodder (1939b) record the discovery of spores in the following yeasts formerly reported as asporogenous, with the changes in nomenclature in-dicated: Monilia pinoyisimilis and Monilia pseudotropicalis = Saccharomyces fragilis; Monilia macedoniensis = Saccharomyces macedoniensis; Monilia javanica = Hansenula anomala; Candida pelliculosa = Hansenula javanica. Todd and Herrmann (1936), confirmed by Giordano (1939), noted that many strains of pathogenic yeasts formerly referred to as Torula histolytica, Torula hominis, etc. actually form spores of such a character as to warrant referring them to the genus Debaryomyces.…”

“…A further step in establishing the identity of this yeast was made by Todd and Herrmann (1936) who described the formation of ascospores. Studying two strains (one isolated at the University of Iowa, the other from Minnesota) from cases of torula meningitis, they observed spore formation in cultures aged until the medium began to dry (3 to 6 weeks) using Sabouraud's glucose or maltose agar.…”