Abstract
Carbohydrate-containing extracts were prepared from mature yeast colonies grown on Sabouraud dextrose agar by mixing a 0.001-ml loopful of yeast cells for 30 s in phenolized saline and removing the cells by centrifugation. Extracts were prepared from 54 Cryptococcus neoformans isolates, 29 isolates of other Cryptococcus species, 16 isolates of Candida species, 2 Rhodotorula, 2 Torulopsis, and 1 Saccharomyces species. Initially the carbohydrate content of each extract was estimated (Molisch method) and adjusted to 1, 5, and 10 microgram/ml. Twofold dilutions of each extract were tested for reactivity with the cryptococcal latex agglutination reagent of Bloomfield et al. (N. Bloomfield, M.A. Gordon, and D.F. Elmendorf, Jr., Proc. Soc. Exp. Biol. Med. 114:64-67, 1963). All 54 C. neoformans extracts gave strong agglutinations (3+ to 4+) in dilutions of 1:4 or greater. None of the other yeasts produced any agglutination, except for 1 of 15 C. laurentii isolates, which showed a 1+ reaction that disappeared at a dilution of 1:4 and above. Subsequent testing established that a single extract made from 0.001 ml of yeast cells in 6 ml of phenolized saline contained less than 5 microgram of carbohydrate per ml, was suitable for a single rapid screening dilution, and eliminated any cross-reaction from the C. laurentii isolates. In our hands this method has provided a reliable differentiation of C. neoformans from other unknown yeast colonies in less than 20 min exclusive of a Molisch determination.
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- BLOOMFIELD N., GORDON M. A., ELMENDORF D. F., Jr DETECTION OF CRYPTOCOCCUS NEOFORMANS ANTIGEN IN BODY FLUIDS BY LATEX PARTICLE AGGLUTINATION. Proc Soc Exp Biol Med. 1963 Oct;114:64–67. doi: 10.3181/00379727-114-28586. [DOI] [PubMed] [Google Scholar]
- Felton F. G., Muchmore H. G., McCarty M. A. Epidemiology of cryptococcosis: I. Environmental distribution of cryptococci in Oklahoma. Health Lab Sci. 1974 Jul;11(3):201–204. [PubMed] [Google Scholar]
- Healy M. E., Dillavou C. L., Taylor G. E. Diagnostic medium containing inositol, urea, and caffeic acid for selective growth of Cryptococcus neoformans. J Clin Microbiol. 1977 Oct;6(4):387–391. doi: 10.1128/jcm.6.4.387-391.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hopfer R. L., Gröschel D. Six-hour pigmentation test for the identification of Cryptococcus neoformans. J Clin Microbiol. 1976 Aug;2(2):96–98. [PMC free article] [PubMed] [Google Scholar]
- Korth H., Pulverer G. Pigment formation for differentiating Cryptococcus neoformans from Candida albicans. Appl Microbiol. 1971 Mar;21(3):541–542. doi: 10.1128/am.21.3.541-542.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Staib F., Seeliger H. P. Un nouveau milieu sélectif pour l'isolement de C. neoformans des matières fécales et du sol. Ann Inst Pasteur (Paris) 1966 May;110(5):792–793. [PubMed] [Google Scholar]
- Vickers R. M., McElligott J. J., Jr, Rihs J. D., Postic B. Medium containing trypan blue and antibiotics for the detection of Cryptococcus neoformans in clinical samples. Appl Microbiol. 1974 Jan;27(1):38–42. doi: 10.1128/am.27.1.38-42.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]