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Kwizera R, Akampurira A, Kandole TK, Nabaggala MS, Williams DA, Kambugu A, Meya DB, Rhein J, Boulware DR. Evaluation of trypan blue stain in the TC20 automated cell counter as a point-of-care for the enumeration of viable cryptococcal cells in cerebrospinal fluid. Med Mycol 2018; 56:559-564. [PMID: 29420767 DOI: 10.1093/mmy/myx076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 08/18/2017] [Indexed: 01/06/2023] Open
Abstract
Cerebrospinal fluid (CSF) culture can determine a quantitative viability of Cryptococcus yeasts; however, culture has a long turnaround-time. The TC20 automated cell counter (Bio-Rad) is a benchtop instrument used to count cells in 30 seconds. In vitro studies suggest trypan blue staining can distinguish between viable and dead cryptococcal yeasts. We hypothesized that trypan blue staining with automated cell counting may provide rapid quantification of viable CSF Cryptococcus yeasts. In sum, 96 HIV-infected participants with cryptococcal meningitis were enrolled and provided 194 CSF specimens in Kampala, Uganda. Cryptococcosis was diagnosed by CSF cryptococcal antigen (CRAG). CSF was stained with trypan blue and quantified yeasts with the TC20 cell counter. We compared the log10 transformed cell counter readings with gating of 4-10 μm versus log10 quantitative Cryptococcus cultures/ml. TC20 showed more positive results (95.4%) overall than culture (78.4%) with reference to CSF CRAG. TC20 had higher readings compared to culture in most cases with only a 25% level of agreement between the two methods. TC20 had a poor correlation to culture throughout the 14 days of antifungal therapy. The median of log10 transformed counts were 5.22 (IQR = 4.79-5.44) for the TC20 and 3.99 (IQR = 2.59-5.14) for culture. Overall, a linear regression showed no significant relationship between the TC20 and culture (r = -0.0025; P = .92). TC20 automated cell counting with trypan blue staining was poorly predictive of the quantitative CSF culture and could not be used as a substitute for quantitative culture.
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Affiliation(s)
- Richard Kwizera
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Andrew Akampurira
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Tadeo K Kandole
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Maria S Nabaggala
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Darlisha A Williams
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.,Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew Kambugu
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.,Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - David B Meya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.,Department of Medicine, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda.,Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Joshua Rhein
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.,Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - David R Boulware
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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Evaluation of trypan blue stain in a haemocytometer for rapid detection of cerebrospinal fluid sterility in HIV patients with cryptococcal meningitis. BMC Microbiol 2017; 17:182. [PMID: 28830348 PMCID: PMC5567638 DOI: 10.1186/s12866-017-1093-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/14/2017] [Indexed: 01/13/2023] Open
Abstract
Background Quantitative culture is the most common method to determine the fungal burden and sterility of cerebrospinal fluid (CSF) among persons with cryptococcal meningitis. A major drawback of cultures is a long turnaround-time. Recent evidence demonstrates that live and dead Cryptococcus yeasts can be distinguished using trypan blue staining. We hypothesized that trypan blue staining combined with haemocytometer counting may provide a rapid estimation of quantitative culture count and detection of CSF sterility. To test this, we evaluated 194 CSF specimens from 96 HIV-infected participants with cryptococcal meningitis in Kampala, Uganda. Cryptococcal meningitis was diagnosed by CSF cryptococcal antigen (CRAG). We stained CSF with trypan blue and quantified yeasts using a haemocytometer. We compared the haemocytometer readings versus quantitative Cryptococcus CSF cultures. Results Haemocytometer counting with trypan blue staining had a sensitivity of 98% (64/65), while CSF cultures had a sensitivity of 95% (62/65) with reference to CSF CRAG for diagnostic CSF specimens. For samples that were positive in both tests, the haemocytometer had higher readings compared to culture. For diagnostic specimens, the median of log10 transformed counts were 5.59 (n = 64, IQR = 5.09 to 6.05) for haemocytometer and 4.98 (n = 62, IQR = 3.75 to 5.79) for culture; while the overall median counts were 5.35 (n = 189, IQR = 4.78–5.84) for haemocytometer and 3.99 (n = 151, IQR = 2.59–5.14) for cultures. The percentage agreement with culture sterility was 2.4% (1/42). Counts among non-sterile follow-up specimens had a median of 5.38 (n = 86, IQR = 4.74 to 6.03) for haemocytometer and 2.89 (n = 89, IQR = 2.11 to 4.38) for culture. At diagnosis, CSF quantitative cultures correlated with haemocytometer counts (R2 = 0.59, P < 0.001). At 7–14 days, quantitative cultures did not correlate with haemocytometer counts (R2 = 0.43, P = 0.4). Conclusion Despite a positive correlation, the haemocytometer counts with trypan blue staining did not predict the outcome of quantitative cultures in patients receiving antifungal therapy. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-1093-4) contains supplementary material, which is available to authorized users.
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Racicot TA, Bulmer GS. Comparison of Media for the Isolation of Cryptococcus neoformans. Appl Environ Microbiol 2010; 50:548-9. [PMID: 16346872 PMCID: PMC238661 DOI: 10.1128/aem.50.2.548-549.1985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Four media, Staib's Guizotia abyssinica, trypan blue, and Staib's with 2 and 10 mg of methyl violet per liter, were compared for the selective and differential isolation of Cryptococcus neoformans from environmental samples. Trypan blue medium allowed for the differentiation of C. neoformans colonies from Candida albicans colonies several days earlier than did Staib's medium. The addition of methyl violet to Staib's medium was found to be inhibitory to some strains of all species tested. Diphenyl in Staib's medium inhibited the growth of 30 strains of C. neoformans and C. albicans.
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Affiliation(s)
- T A Racicot
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190
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Abstract
Nearly 10(6) cells of Cryptococcus neoformans were cultured per g of pigeon droppings in a vacant tower. The air in the tower contained an average of 45 viable cells of C. neoformans per 100 liters: 60% of the cells were less than 4.7 micron in diameter. It is estimated that a human exposed to this atmosphere for 1 h would have 41 cells of c. neoformans deposited in the lungs. Sweeping resulted in the aerosolization of large numbers of cells of C. neoformans from 4.7 to 11 micron in diameter, the number of cells less than 4.7 micron remained relatively constant. One minute after sweeping, 4.4% of viable airborne cells of C. neoformans were less than 1.1 micron in diameter. We believe that this is the first report of isolating such small cells of C. neoformans from a natural site.
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Abstract
Pigeon droppings in a vacant tower were assayed for the number and size of viable cells of Cryptococcus neoformans. The dry, thinly scattered floor debris contained 2.6 x 10(6) viable cells per g--300 times more cells than were cultured from a large, compact pile of pigeon droppings (7.4 x 10(3) cells per g). Aerosols generated from floor debris containing pigeon droppings had an average of 360 viable cells in 31 liters of air; 27 of these cells (7.5%) were 1.1 to 3.3 micrometers in diameter and, therefore, capable of human lung deposition. Environmental factors which may influence the distribution, survival, and proliferation of C. neoformans in nature are discussed.
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Muchmore HG, Felton FG, Scott EN. Rapid presumptive identification of Cryptococcus neoformans. J Clin Microbiol 1978; 8:166-70. [PMID: 359587 PMCID: PMC275181 DOI: 10.1128/jcm.8.2.166-170.1978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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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Neilson JB, Ivey MH, Bulmer GS. Cryptococcus neoformans: pseudohyphal forms surviving culture with Acanthamoeba polyphaga. Infect Immun 1978; 20:262-6. [PMID: 352931 PMCID: PMC421581 DOI: 10.1128/iai.20.1.262-266.1978] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During experiments on the gastrointestinal tract as a possible portal of entry for Cryptococcus neoformans, we occasionally observed the free-living amoeba, Acanthamoeba polyphaga, growing in the presence of C. neoformans cultured from mouse feces. Examination of the amoebic trophozoites revealed that they were engorged with yeast cells. Over a period of 2 to 3 weeks of incubation, the amoebae apparently killed most of the yeast cells. Some of the surviving C. neoformans cells formed atypical colonies which contained pseudohyphae. Seven other strains have since been cultured with this amoeba. Pseudohyphal forms were found among the surviving colonies in all strains tested. Virulence studies were performed on one randomly selected pseudohyphal isolate from each of the eight strains of C. neoformans. Pseudohyphal isolates from seven of the eight strains failed to kill mice 30 days after intracranial inoculation. The potential role of soil amoebae in the control of C. neoformans in nature is discussed.
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Moser SA, Friedman L, Varraux AR. Atypical isolate of Cryptococcus neoformans cultured from sputum of a patient with pulmonary cancer and blastomycosis. J Clin Microbiol 1978; 7:316-8. [PMID: 348724 PMCID: PMC274926 DOI: 10.1128/jcm.7.3.316-318.1978] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus neoformans was isolated repeatedly from a patient with epider-moid carcinoma and pulmonary blastomycosis. The isolate was atypical in that it had only a minute capsule, caused persistent infection but no perceptible disease in mice, and initially appeared not to assimilate trehalose. Only after an incubation of 2 to 3 weeks did utilization of this substrate become apparent.
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Neilson JB, Fromtling RA, Bulmer GS. Cryptococcus neoformans: size range of infectious particles from aerosolized soil. Infect Immun 1977; 17:634-8. [PMID: 332630 PMCID: PMC421174 DOI: 10.1128/iai.17.3.634-638.1977] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although cryptococcosis is characterized as a chronic central nervous system disease, it is generally accepted that the lungs are the primary portal of entry for the etiological agent. Despite this, there is a distinct lack of evidence that viable airborne particles of Cryptococcus neoformans are small enough to reach the alveoli. Two encapsulated strains and one nonencapsulated strain of C. neoformans were inoculated into 250-g quantities of sterile soil. Throughout the 0 to 12 weeks of incubation, this soil was aerosolized in a sealed chamber with a Waring blender. Samples of the resultant dust cloud were taken with an Anderson air sampler from which the numbers and sizes of viable airborne particles were determined. Of the viable organisms aspirated into the air sampler, 15% were 0.65 to 2 micron in diameter. As incubation time in soil increased, the size of the particles decreased, and increased numbers of C. neoformans cells 0.65 to 2 micron in diameter were isolated. The presence of viable cells less than 2 micron in soil aerosols indicated that, under certain conditions in nature, C. neoformans cells exist in sizes that are capable of deep lung deposition.
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Fleming WH, Hopkins JM, Land GA. New culture medium for the presumptive identificaion of Candida albicans and Cryptococcus neoformans. J Clin Microbiol 1977; 5:236-43. [PMID: 321472 PMCID: PMC274567 DOI: 10.1128/jcm.5.2.236-243.1977] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A new medium composed of Tween 80, oxgall, caffeic acid, and Davis agar (TOC) that provides for the rapid presumptive identification of Candida albicans and Cryptococcus neoformans is described herein. C. albicans is differentiated from other yeasts by the sequential production of germ tubes and chlamydospores. In a comparison with cormeal agar control plates, there was an increase of chlamydospore-forming strains of C. albicans (97.1% versus 87.2%) and a decrease in the time required for chlamydospore formation (24 h versus 48 h). C. neoformans produced a brown pigment of TOC, which is specific for its identification, thus differentiating it from the other yeasts. A comparison of 24-h pigment production by C. neoformans on TOC with that of birdseed agar showed a dark, coffee brown color in the former cultures and a light brown color in the latter. The change in pigmentation of C. neoformans, as well as morphological changes in C. albicans, can be induced within 3 to 12 h and in not more than 24 h on the TOC medium.
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