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PubMed1992

[Physiological characteristics of the strains of Cryptococcus deffluens--producers of penicillin acylase].

A fermentation medium balanced by the main components was developed for Cryptococcus diffluens strains producing penicillin-V-acylases (PA). It was shown that the culture needed for production of the enzyme was inductor, which was phenoxyacetic acid (POAA). Additional introduction of ethanol to the medium provided an increase in production of PA by 36 per cent and the culture growth by 25 per cent. Introduction of one of the following substances to the medium with POAA and ethanol i.e. (CN3COO)2Ca, FeSO4, proline or asparagine provided an additional increase in the production level of PA by 24 to 94 per cent. The use of the medium varieties will permit one to isolate highly productive cells of the culture.

Amino Acids↗
PubMed1992

Isolation of Cryptococcus neoformans var. gattii from an Asian patient in France: evidence for dormant infection in healthy subjects.

We report the first case of cryptococcosis due to Cryptococcus neoformans var. gattii in France. This Cambodian, non-AIDS patient had been living in France for 23 years when he developed cryptococcosis due to C. neoformans serotype B in 1985. It is possible that he was infected back in Asia or several months before, in Zaire, where he lived between 1981 and 1984. To our knowledge, this is the second case providing clinical evidence for reactivation of latent infection with C. neoformans. The mechanism is probably similar to that for C. neoformans var. neoformans.

Adult↗
PubMed1992

Environmental isolation of Cryptococcus neoformans var. gattii from Eucalyptus tereticornis.

As an extension of the previously established association between Cryptococcus neoformans var. gattii and Eucalyptus camaldulensis (River red gum) we have now found a similar relationship between C. neoformans var. gattii and the closely related Eucalyptus tereticornis (Forest red gum). The global distribution of E. tereticornis is similar to that of E. camaldulensis.

Cryptococcus neoformans↗
PubMedDate not supplied

[Cryptococcosis caused by Cryptococcus neoformans var. Gattii. A case associated with acquired immunodeficiency syndrome (AIDS) in Kinshasa, Zaire].

Since the introduction of AIDS, the biovar neoformans of Cryptococcus neoformans has replaced the biovar gattii as the predominant agent of cryptococcal meningitis in Kinshasa and in other tropical areas. That this is not an absolute rule is demonstrated by the present case of a HIV-positive patient, observed at the Kinshasa University Hospital, with cryptococcal meningitis due to the biovar gattii. Only four cases of this association have been published before. The authors conclude that both biovars are capable of infecting HIV-positive patients but that the apparent decline of the biovar gattii is related to the rarity of its natural reservoir in the urban environment, where the AIDS epidemic is concentrated.

AIDS-Related Opportunistic Infections↗
PubMed2004

Susceptibility of the human pathogenic fungi Cryptococcus neoformans and Histoplasma capsulatum to gamma-radiation versus radioimmunotherapy with alpha- and beta-emitting radioisotopes.

UNLABELLED: Fungal diseases are difficult to treat in immunosuppressed patients and, consequently, new approaches to therapy are urgently needed. One novel strategy is to use radioimmunotherapy (RIT) with fungal-binding monoclonal antibodies (mAbs) labeled with radionuclides. However, many fungi manifest extreme resistance to gamma-radiation, such that the doses of several thousand gray are required for 90% cell killing, whereas for mammalian cells the lethal dose is only a few gray. We compared the susceptibility of human pathogenic fungi Cryptococcus neoformans (CN) and Histoplasma capsulatum (HC) to external gamma-radiation and to the organism-specific mAbs 18B7 and 9C7, respectively, conjugated to (213)Bi and (188)Re radionuclides. METHODS: CN and HC cells were irradiated with up to 8,000 Gy ((137)Cs source, 30 Gy/min). RIT of CN with (213)Bi- and (188)Re-labeled specific mAb and of HC with (188)Re-labeled specific mAb used 0-1.2 MBq per 10(5) microbial cells. After irradiation or RIT, the cells were plated for colony-forming units (CFUs). Cellular dosimetry calculations were performed, and the pathway of cell death after irradiation was evaluated by flow cytometry. RESULTS: Both CN and HC proved to be extremely resistant to gamma-radiation such that significant killing was observed only for doses of >4,000 Gy. In contrast, these cells were much more susceptible to killing by radiation delivered with a specific mAb, such that a 2-logarithm reduction in colony numbers was achieved by incubating them with (213)Bi- and (188)Re-labeled mAb 18B7 or with (188)Re-9C7 mAb. Dosimetry calculations showed that RIT was approximately 1,000-fold more efficient in killing CN and approximately 100-fold more efficient in killing HC than gamma-radiation. Both gamma-radiation and RIT caused cell death via an apoptotic-like pathway with a higher percentage of apoptosis observed in RIT-treated cells. CONCLUSION: Conjugating a radioactive isotope to a fungal-specific antibody converted an immunoglobulin with no antifungal activity into a microbicidal molecule. RIT of fungal cells using specific antibodies labeled with alpha- and beta-emitting radioisotopes was significantly more efficient in killing CN and HC than gamma-radiation when based on the mean absorbed dose to the cell. These results strongly support the concept of using RIT as an antimicrobial modality.

Antibodies, Monoclonal↗
PubMed1992

4-oxatetradecanoic acid is fungicidal for Cryptococcus neoformans and inhibits replication of human immunodeficiency virus I.

Candida albicans and Cryptococcus neoformans are major causes of systemic fungal infections, particularly in patients with acquired immunodeficiency syndrome. Metabolic labeling studies revealed that these organisms synthesize a small number of N-myristoylproteins, the most prominent being 20-kDa ADP-ribosylation factors (Arfs). C. albicans Arf has approximately 80% identity with the essential Arf1 and Arf2 proteins of Saccharomyces cerevisiae. [3H]Myristic acid analogs with oxygen for -CH2- substitutions at C4, C6, C11, and C13 are incorporated into cellular N-myristoylproteins, phospholipids, and neutral lipids produced by these three yeasts during exponential growth at 30 degrees C in complex media. Analog- and organism-specific differences in the efficiency of labeling of proteins and lipid classes were observed. The effects of oxatetradecanoic acids with oxygen for -CH2- substitutions at C3-C13 on C. neoformans, C. albicans, and S. cerevisiae were assessed during mid-log phase growth at 30 degrees C. A single dose of 3-oxa-, 4-oxa-, 5-oxa- or 6-oxatetradecanoic acid (O3-O6, final concentration = 300 microM) was able to inhibit growth of C. neoformans in the order O4 greater than O5 greater than O3 approximately O6. The other compounds were inactive. 4-Oxatetradecanoic acid was fungicidal, producing a 10,000-fold reduction in viable cell number 1 h after administration and continued suppression of cell growth for 7 h. A clear dose response was observed over a concentration range of 100-300 microM. 4-Oxatridecanoic acid was 100-fold less potent in reducing cell viability than 4-oxatetradecanoic acid but more potent than 5-oxatridecanoic acid. O4 produced approximately 10-100-fold reductions in the viability of C. albicans and S. cerevisiae at 300-500 microM, respectively, whereas O5 and O6 were less active. Since N-myristoylation of the Pr55gag polyprotein precursor produced by human immunodeficiency virus I (HIV-I) is essential for its assembly, we also assessed the antiviral effects of 4-oxatetradecanoic acid. O4 is able to produce a 50% reduction in the replication of HIV-I in acutely infected human T-lymphocyte cell lines at a concentration of 18 microM. Together, these data suggest that (i) the position of the oxygen for methylene substitution is a critical determinant of the fungicidal activity of O4 and (ii) NMT may be an attractive therapeutic target for treating opportunistic fungal infections in patients infected with HIV-I.

ADP-Ribosylation Factor 1↗
PubMed2004

Serotypes of clinical cerebrospinal fluid Cryptococcus neoformans isolates from southern Taiwan and their in vitro susceptibilities to amphotericin B, fluconazole, and voriconazole.

In this study, 34 clinical cerebrospinal fluid isolates of Cryptococcus neoformans were serotyped, and their in vitro susceptibilities to amphotericin B, fluconazole, and voriconazole were analyzed. Of these 34 isolates, serotype A was found in 29 isolates and serotype B in the other five. The voriconazole geometric mean MIC was significantly lower than the amphotericin B/antibiotic medium 3 geometric mean MIC (P < 0.0001 at both 48 and 72 h), as well as the fluconazole geometric mean MIC (P < 0.0001 at both 48 and 72 h). Of the three antifungal agents, only fluconazole, with geometric mean MICs at both 48 and 72 h, showed significant difference between the serotypes A and B of C. neoformans.

Amphotericin B↗
PubMed2004

Regulation by innate immune T lymphocytes in the host defense against pulmonary infection with Cryptococcus neoformans.

Recently, innate immune lymphocytes, such as natural killer (NK) T cells and gamma/delta antigen receptor-bearing T (gamma delta T) cells, have garnered much attention, and their biological significance in the tumor immunity, allergic diseases and infectious diseases is extensively exploited. We have addressed the role of these cells in the host defense using a mouse model of pulmonary infection with Cryptococcus neoformans, which frequently causes fatal meningoencephalitis in AIDS patients. Host defense to this fungal pathogen is largely mediated by cellular immunity, and type-1 helper T (Th1) cells play a central role in this process. This infection causes a prompt accumulation of both NKT and gamma delta T cells in the lung tissues in a monocyte chemoattractant protein (MCP)-1-dependent or -independent manner, respectively. Genetic deletion of V alpha 14+ NKT cells ameliorates the Th1 response and clearance of microorganisms in the lungs, whereas these host protective responses are rather enhanced in mice lacking gamma delta T cells. Thus, in some aspect, these innate immune lymphocytes may co-regulate the Th1-mediated response for induction of the moderate host defense. gamma delta T cells may act to keep the balance of Th1-Th2 responses in a proper manner by suppressing the exaggerated Th1 response caused by NKT cells. In this review, I describe the recent research development in the innate immune host defense against cryptococcal infection in respiratory organs with emphasis on our data in the regulatory role of NKT cells and gamma/delta T cells.

Animals↗
PubMed2004

A new caffeic acid minimal synthetic medium for the rapid identification of Cryptococcus neoformans isolates.

Melanin production is one of the most important criteria for rapid identification of Cryptococcus neoformans. Most of the media described in the literature for identifying C. neoformans are very complex; they contain many organic or inorganic compounds and are difficult to prepare and store. The new minimal synthetic caffeic acid medium described in this paper is simpler to prepare, convenient and constitutes an interesting new medium for the rapid identification of C. neoformans isolates.

Caffeic Acids↗
PubMed2005

Cryptococcus neoformans peritonitis in two patients with liver cirrhosis.

Cryptococcus neoformans is an important pathogen in immunocompromised patients. We report 2 cases of spontaneous C. neoformans peritonitis in patients with liver cirrhosis, a condition not previously reported in Taiwan. Patient 1, a 59-year-old man with alcoholic liver cirrhosis, had primary C. neoformans peritonitis with fungemia. The patient recovered completely after prolonged fluconazole therapy without relapse. Patient 2, a 51-year-old woman with liver cirrhosis due to Budd-Chiari syndrome, had C. neoformans isolated from ascites, cerebrospinal fluid, and blood culture. In spite of adequate antifungal treatment, the patient died of fulminant sepsis. Information about the interaction and relation between liver cirrhosis and cryptococcal peritonitis is rare in the literature. The experience of these cases may help facilitate the diagnosis and treatment of cryptococcal peritonitis.

Cryptococcosis↗
PubMed1992

Selection of ura5 and ura3 mutants from the two varieties of Cryptococcus neoformans on 5-fluoroorotic acid medium.

Spontaneous mutants requiring uracil were isolated from both varieties of Cryptococcus neoformans by plating on 5-fluoroorotic acid (5-FOA) medium. Of the 36 strains tested (18 var. neoformans and 18 var. gattii), 24 (12 of each variety) generated 5-FOA-resistant cells requiring uracil for growth. Six of the 12 C. neoformans var. gattii strains produced ura3 cells while the remaining six strains produced ura5 cells. None of the 12 strains produced both ura3 cells and ura5 cells. All 12 isolates of var. neoformans, however, produced ura5 cells and one of them produced ura3 as well as ura5 cells. A genetic lesion in the URA5 gene of an isolate of C. neoformans var. gattii was confirmed by complement with the cognate URA5 gene of C. neoformans var. neoformans. The ura3 isolates were tentatively identified by their ability to grow on a medium containing uridine but not on a medium with orotic acid or orotidine. Enzymatic assays for orotidine-5'-phosphate decarboxylase activity confirmed the isolates to be ura3 mutants. Hybridization analysis of total DNA, digested with EcoRI or StuI and probed with pURA5g2, revealed the presence of only one copy of URA5 in the strains of either variety, regardless of the prevalence of ura5 mutants. Extensive polymorphism was observed in the restriction patterns of the fragments containing the URA5 locus. The prevalence of spontaneously arising ura3 mutants among the isolates of C. neoformans var. gattii, but not among the isolates of C. neoformans var. neoformans, is one more biological difference that distinguishes the two varieties.

Animals↗
PubMedDate not supplied

[Obtention of specific antisera for the serotyping of Cryptococcus neoformans var. neoformans].

The obtention of antisera at the Mycology Laboratory of "Pedro Kouri" Institute of Tropical Medicine was proposed to allow the rapid identification of the varieties and serotypes of Cryptococcus neoformans, since it is very important from the clinico-epidemiological point of view to know them. By immunizing rabbits with formalized whole cells of the 4 serotypes of this yeast, it was possible to obtain antisera that were absorbed with cells of the heterologous serotypes. 3 antisera capable of differentiating the neoformans var. (anti AD) and its respective serotypes (anti-A and anti-D) were attained. This paper will contribute to the knowledge of the epidemiology of this important disease in the Cuban setting for being the first time that useful antisera are obtained in Cuba to identify the serotypes corrresponding to the neoformans variety, which is the main causal agent of criptococcosis.

Cryptococcus neoformans↗
PubMedDate not supplied

[Usefulness of D-proline in the differentiation of varieties of Cryptococcus neoformans].

A comparative study was conducted between the assimilation of D-proline and the growth on canavanine-glycine-bromothymol blue (CGB) medium used for the classification of the varieties of Cryptococcus neoformans. In the 86 studied strains, 100% of coincidence between both methods allowed to affirm that 95.34% corresponded to the neoformans var. and the rest (4.65%) to the gattii var. The results obtained corroborated that all the autoctonous clinical isolations up to the present correspond to the. neoformans var. and made possible to suggest the use of D-proline for the initial evaluation of strains, as an alternative and simple method that presented under these conditions high coincidence with the reference method (growth in CGB).

Cryptococcus neoformans↗
PubMedDate not supplied

[Pigmentation of Cryptococcus neoformans strains on sunflower seed agar].

The production of melanin on a medium of sunflower seeds extract agar from 86 strains of Cryptococcus neoformans belonging to the Mycology Laboratory of "Pedro Kouri" Institute of Tropical Medicine was determined. 54.7% of them produced colonies with dark brown pigment, 5.8% a light pigment and 37.2% an intermediate tonality. A fourth group was created for those strains with a true pigment (2.3%). This paper is an important contribution to attain a better characterization of the strains from the collection of the institution and serves as a basis to further studies of pathogenicity and susceptibility.

Agar↗
PubMed1992

The interaction of Cryptococcus neoformans with primary rat lung cell cultures.

Conditions under which Cryptococcus neoformans adhered to and was internalized by primary lung epithelial cell cultures were studied. Adherence was affected by the yeast culture age, glucose concentration and growth temperature. Formalin or heat treatment did not affect yeast adherence. Trypsin treatment, however, inhibited adherence.

Animals↗
PubMedDate not supplied

[Antiphytoviral activity of capsule substances of Cryptococcus albidus yeast].

The yeast Cryptococcus albidus isolated from the leaves of maize (strain 1003) and cucumbers (strain 1014) produce the capsule substances which can protect the tobacco and datura plants from tobacco mosaic virus. Proteins, carbohydrates and ash elements have been isolated from culture liquids treated by supersound.

Antiviral Agents↗
PubMed2005

Isolation of Cryptococcus neoformans var. grubii (serotype A) from pigeon droppings in Seoul, Korea.

Seventy-two pigeon dropping samples were collected from 26 different localities in Seoul and investigated for the occurrence of Cryptococcus neoformans. Seventeen samples from 8 different localities were found to be positive for C. neoformans. All isolates were obtained from withered pigeon droppings. Identification and serotyping of the isolates were determined by means of serological testing and DNA fingerprinting. All isolates belonged to C. neoformans var. grubbi (serotype A).

Animals↗
PubMed2006

Antifungal susceptibilities of Cryptococcus neoformans cerebrospinal fluid isolates and clinical outcomes of cryptococcal meningitis in HIV-infected patients with/without fluconazole prophylaxis.

OBJECTIVES: To compare the MICs of FLUconazole (FLU) and amphotericin B against isolates of Cryptococcus neoformans (C. neoformans) obtained from the CerebroSpinal Fluid (CSF); and clinical outcomes of HIV-infected patients diagnosed with cryptococcal meningitis. MATERIAL AND METHOD: There were two groups including those who did not receive FLU (group A) and those who did receive either FLU 400 mg/week for primary prophylaxis cryptococosis or 200 mg/day for secondary prophylaxis cryptococosis (group B). CSF isolates of C. neoformans from group A and group B between January 2003 and October 2004 were retrospectively studied. The MICs were determined by using the standard NCCLS broth microdilution methods (M27-A). The MICs of FLU and amphotericin B, and clinical outcomes after 10 weeks of cryptococcal meningitis treatment were determined. RESULTS: There were 98 isolates; 80 in group A and 18 in group B. The patients in group B had a higher proportion of previous opportunistic infections (p = 0.008). The other baseline characteristics between the two groups were not different. The median (range) MIC of FLU was 8.0 (0.5-32) microg/ml in group A, and 6.0 (0.5-32) microg/ml in group B (p = 0.926). The median (range) MIC of amphotericin B was 0.25 (0.03-1.0) microg/ml in group A, and 0.25 (0.12-1.0) microg/ml in group B (p = 0.384). Sixty patients from group A and 14 from group B received standard treatment and continued to follow-up. After the 10-week treatment, 39/60 (65%) patients in group A and 7/14 (50%) in group B had complete recovery (p = 0.364; RR = 0.538, 95%CI = 0.166-1.742). The overall mortality rate was 14/60 (23.3%) in group A and 7/14 (50.0%) in group B (p = 0.096; RR = 3.286, 95%CI = 0.983-10.979). CONCLUSION: The MICs of FLU and amphotericin B against CSF isolates of C. neoformans and clinical outcomes between HIV-infected patients who receive or did not receive FLU prophylaxis are not different.

AIDS-Related Opportunistic Infections↗