This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Savage, D. C. Articles by Dubos, R. J. Search for Related Content PubMed PubMed Citation Articles by Savage, D. C. Articles by Dubos, R. J.

Localization of Indigenous Yeast in the Murine Stomach

The Rockefeller University, New York, New York 10021

ABSTRACT

Certain strains of yeast were cultured frequently from the feces of adult CFW mice and Long-Evans and Sprague-Dawley rats, but not from infants of those murine strains, or from adults or infants of NCS or NCS-D mice. When the yeasts could be cultured from the feces, they could also be grown from all areas of the digestive tracts of the animals, but especially from the stomachs, where they formed layers on the epithelium of the glandular mucosa. Three of the yeast isolates, one each from the three murine colonies, were provisionally classified in the genus Torulopsis of the asporogenous yeasts. These yeast strains failed to colonize the digestive tubes of suckling infant mice of either the CFW or NCS-D colonies. In contrast, they colonized the guts of adult NCS-D mice and formed layers in their stomachs; tests with the yeast from CFW mice revealed that this strain colonized the guts and formed layers in the stomachs of germ-free CFW mice. When established in NCS-D mice, the yeast strains did not affect qualitatively or quantitatively the growth of the animals or the composition of the bacterial flora in the gastrointestinal tracts. Moreover, they did not elicit an unusual inflammatory response in the digestive tracts; nor were they pathogenic for NCS mice when injected by the intraperitoneal or intravenous routes. The yeasts thus appear to be harmless saprophytes that are able to flourish in the environment of the surface of the secreting epithelium of the murine stomach. The findings conform with the view that some types of microorganisms of the gastrointestinal tract are not just mixed randomly but rather occupy microenvironments in almost pure culture. This concept is important to the understanding of the ecology of the gut microflora.

¹ Present address: Department of Microbiology, University of Texas, Austin 78712.