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Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing.
J Clin Microbiol. 2011 Jul; 49(7):2522-7.JC

Abstract

Rapid identification of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii is imperative for facilitation of prompt treatment of cryptococcosis and for understanding the epidemiology of the disease. Our purpose was to evaluate a test algorithm incorporating commercial rapid biochemical tests, differential media, and DNA sequence analysis that will allow us to differentiate these taxa rapidly and accurately. We assessed 147 type, reference, and clinical isolates, including 6 other Cryptococcus spp. (10 isolates) and 14 other yeast species (24 isolates), using a 4-hour urea broth test (Remel), a 24-hour urea broth test (Becton Dickinson), a 4-hour caffeic acid disk test (Hardy Diagnostics and Remel), 40- to 44-hour growth assessment on l-canavanine glycine bromothymol blue (CGB) agar, and intergenic spacer (IGS) sequence analysis. All 123 Cryptococcus isolates hydrolyzed urea, along with 7 isolates of Rhodotorula and Trichosporon. Eighty-five of 86 C. neoformans (99%) and 26 of 27 C. gattii (96%) isolates had positive caffeic acid results, unlike the other cryptococci (0/10) and yeast species (0/24). Together, these two tests positively identified virtually all C. neoformans/C. gattii isolates (98%) within 4 h. CGB agar or IGS sequencing further differentiated these isolates within 48 h. On CGB, 25 of 27 (93%) C. gattii strains induced a blue color change, in contrast to 0 of 86 C. neoformans isolates. Neighbor-joining cluster analysis of IGS sequences differentiated C. neoformans var. grubii, C. neoformans var. neoformans, and C. gattii. Based on these results, we describe a rapid identification algorithm for use in a microbiology laboratory to distinguish clinically relevant Cryptococcus spp.

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Authors+Show Affiliations

McTaggart L
Medical Mycology, Ontario Public Health Laboratories, Ontario Agency for Health Protection and Promotion, Department ofLaboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Richardson SE
No affiliation info available
Seah C
No affiliation info available
Hoang L
No affiliation info available
Fothergill A
No affiliation info available
Zhang SX
No affiliation info available

MeSH

CryptococcosisCryptococcus neoformansCulture MediaDNA, FungalHumansMolecular TypingMycological Typing TechniquesSequence Analysis, DNATime Factors

Pub Type(s)

Evaluation Study
Journal Article

Language

eng

PubMed ID

21593254

Citation

McTaggart, Lisa, et al. "Rapid Identification of Cryptococcus Neoformans Var. Grubii, C. Neoformans Var. Neoformans, and C. Gattii By Use of Rapid Biochemical Tests, Differential Media, and DNA Sequencing." Journal of Clinical Microbiology, vol. 49, no. 7, 2011, pp. 2522-7.
McTaggart L, Richardson SE, Seah C, et al. Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing. J Clin Microbiol. 2011;49(7):2522-7.
McTaggart, L., Richardson, S. E., Seah, C., Hoang, L., Fothergill, A., & Zhang, S. X. (2011). Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing. Journal of Clinical Microbiology, 49(7), 2522-7. https://doi.org/10.1128/JCM.00502-11
McTaggart L, et al. Rapid Identification of Cryptococcus Neoformans Var. Grubii, C. Neoformans Var. Neoformans, and C. Gattii By Use of Rapid Biochemical Tests, Differential Media, and DNA Sequencing. J Clin Microbiol. 2011;49(7):2522-7. PubMed PMID: 21593254.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing. AU - McTaggart,Lisa, AU - Richardson,Susan E, AU - Seah,Christine, AU - Hoang,Linda, AU - Fothergill,Annette, AU - Zhang,Sean X, Y1 - 2011/05/18/ PY - 2011/5/20/entrez PY - 2011/5/20/pubmed PY - 2011/9/29/medline SP - 2522 EP - 7 JF - Journal of clinical microbiology JO - J Clin Microbiol VL - 49 IS - 7 N2 - Rapid identification of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii is imperative for facilitation of prompt treatment of cryptococcosis and for understanding the epidemiology of the disease. Our purpose was to evaluate a test algorithm incorporating commercial rapid biochemical tests, differential media, and DNA sequence analysis that will allow us to differentiate these taxa rapidly and accurately. We assessed 147 type, reference, and clinical isolates, including 6 other Cryptococcus spp. (10 isolates) and 14 other yeast species (24 isolates), using a 4-hour urea broth test (Remel), a 24-hour urea broth test (Becton Dickinson), a 4-hour caffeic acid disk test (Hardy Diagnostics and Remel), 40- to 44-hour growth assessment on l-canavanine glycine bromothymol blue (CGB) agar, and intergenic spacer (IGS) sequence analysis. All 123 Cryptococcus isolates hydrolyzed urea, along with 7 isolates of Rhodotorula and Trichosporon. Eighty-five of 86 C. neoformans (99%) and 26 of 27 C. gattii (96%) isolates had positive caffeic acid results, unlike the other cryptococci (0/10) and yeast species (0/24). Together, these two tests positively identified virtually all C. neoformans/C. gattii isolates (98%) within 4 h. CGB agar or IGS sequencing further differentiated these isolates within 48 h. On CGB, 25 of 27 (93%) C. gattii strains induced a blue color change, in contrast to 0 of 86 C. neoformans isolates. Neighbor-joining cluster analysis of IGS sequences differentiated C. neoformans var. grubii, C. neoformans var. neoformans, and C. gattii. Based on these results, we describe a rapid identification algorithm for use in a microbiology laboratory to distinguish clinically relevant Cryptococcus spp. SN - 1098-660X UR - https://www.unboundmedicine.com/medline/citation/21593254/Rapid_identification_of_Cryptococcus_neoformans_var__grubii_C__neoformans_var__neoformans_and_C__gattii_by_use_of_rapid_biochemical_tests_differential_media_and_DNA_sequencing_ L2 - https://journals.asm.org/doi/10.1128/JCM.00502-11?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -