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PubMed2006

Antifungal susceptibility of Cryptococcus neoformans to amphotericin B and fluconazole.

Cryptococcus neoformans has emerged as an important opportunistic fungal pathogen in immunocompromised individuals. The therapeutic options of C. neoformans an opportunistic fungal pathogen include flucytosine, amphotericin B, and azole agents. However in the present scenario, emergence of resistance has been reported, hence this study was undertaken to evaluate antifungal susceptibility pattern of C. neoformans isolates from this southern part of India. Ten isolates of C. neoformans were tested against Amp B and fluconazole, of which 7 were susceptible to both and a single isolate of C. neoformans var gatti was resistant to both with MIC of 32mg/ml and 64mg/ml respectively.

Amphotericin B↗
PubMed2006

Clinical characteristics and predictors of mortality for Cryptococcus gattii infection in dogs and cats of southwestern British Columbia.

Since 1999, Cryptococcus gattii has emerged as an important pathogen of humans and animals in southwestern British Columbia. Historically thought to be restricted to the tropics and subtropics, C. gattii has posed new diagnostic and treatment challenges to veterinary practitioners working within the recently identified endemic region. Clinical reports of canine and feline cryptococcosis caused by C. gattii diagnosed between January 1999 and December 2003 were included in this case series. The most common manifestations of disease were respiratory and central nervous system signs. Multivariate survival analysis revealed that the only significant predictor of mortality was the presence of central nervous system signs upon presentation or during therapy. Case fatality rates in both species were high. Further investigation into effective treatment regimes is warranted.

Animals↗
PubMedDate not supplied

[Identification of varieties of Cryptococcus neoformans by the use of culture media].

Ten Cryptococcus neoformans strains of human origin were studied in order to know their variety by using 2 different culture mediums: creatinine-bromothymol-blue-dextrose and glycine-cycloheximide-phenol red. The results obtained in the two mediums were not totally coincidental. The possible causes and the specificity of these mediums for identifying C. neoformans varieties are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[The defensive role of human pulmonary alveolar macrophages and polymorphonuclear leukocytes against a strongly or weakly virulent strains of Cryptococcus neoformans].

The phagocytic and killing activities of human pulmonary alveolar macrophages (PAM) and polymorphonuclear leukocytes (PMN), and superoxide (O2-) production in phagocytizing PAM and PMN were studied by using a strongly and weakly virulent strains of Cryptococcus neoformans (C. neoformans) in mice. The strongly virulent strain was encapsulated with a thick capsule while the other had a thin one. The phagocytic and killing activities of PAM and PMN against the strongly virulent strain were lower than against the weakly virulent one. There was no significant difference between PAM and PMN in terms of phagocytic or killing activities and O2- production. It seems likely that O2- plays no defensive role in the intracellular killing of C. neoformans by PAM and PMN because no correlation was found between the killing activity and O2- production. These results indicate that human PAM and PMN play an effective role in host defense against the weakly virulent strain of C. neoformans encapsulated with a thin capsule but are not effective against the strongly virulent strain encapsulated with a thick capsule.

Adolescent↗
PubMed1991

[The occurrence of Cryptococcus neoformans in fecal samples from birds kept in human living areas].

With help of Guizotia creatinine agar (syn. bird seed agar) Cryptococcus (Cr.) neoformans var. neoformans was isolated from 71 (7.7%) of 925 investigated droppings of birds kept within human living area. Cr. neoformans was detected in droppings of 1.2% from 164 psittacines, in droppings of 1.7% from 118 budgerigars and in droppings of 18.4% from (carrier) pigeons. This yeast was not isolated from droppings of 13 small parrots, 10 eclectus parrots, 13 rosellas, 21 cockatiels, 6 Polytelidus sp., 32 Cacatua sp., 13 Carduelis sp., 5 waxbills, 5 starlings, 120 chicken, 9 turkeys, 2 geese, 2 Turdus sp., 1 duck and 1 gull.

Animals↗
PubMedDate not supplied

[Detection of capsular polysaccharide antigen of Cryptococcus neoformans in patients with AIDS and neurocryptococcosis in São Paulo, Brazil].

Capsular polysaccharide antigen (AgPC) of Cryptococcus neoformans was detected by latex agglutination technique (LA) in cerebrospinal fluid and serum of patients with AIDS during their first central nervous system manifestation of the disease. Direct mycological examination and culture were used as controls. Sensitivity was 100% by LA allowing an early specific treatment of cryptococcosis. Initial titres of AgPC in such patients can be > 1000000 and it appears that when such titres are present in the serum they are related to mortality during treatment. Surviving patients showed positivity of the direct mycological examination and AgPC of C. neoformans in cerebrospinal fluid and sera even after treatment and clinical recovery.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cumulative positivity rates of multiple blood cultures for Mycobacterium avium-intracellulare and Cryptococcus neoformans in patients with the acquired immunodeficiency syndrome.

We examined the occurrence of low-grade Mycobacterium avium-intracellulare bacteremia and Cryptococcus neoformans fungemia in patients with the acquired immunodeficiency syndrome and the consistency of positive cultures obtained using a sensitive blood culture system (Isolator, E. I. Du Pont de Nemours, Wilmington, Del) for the recovery of these organisms. The blood culture records were reviewed, and the proportion of positive blood cultures yielding less than 1 colony-forming unit per milliliter of M avium-intracellulare or C neoformans was calculated. To determine consistency, a period of potentially detectable septicemia was defined as the period between 1 week before the first positive blood culture and the last positive blood culture, providing consecutive positive blood cultures were separated by less than 2 weeks. All positive and negative blood cultures obtained during the period of potentially detectable septicemia were considered in the data analysis. Overall, 40 (16.9%) of 236 cultures positive for M avium-intracellulare and 36 (57.1%) of 63 for C neoformans yielded less than 1 colony-forming unit per milliliter. Mycobacteremia was detected in 52 of 57 periods of potentially detectable septicemia in the first culture and in 56 of 57 in the first two (cumulative detection rates of 91.2% and 98.2%, respectively). Cryptococcemia was detected in 12 of 17 periods of potentially detectable septicemia in the first culture and in 15 of 17 in the first two (cumulative detection rates of 70.6% and 88.2%, respectively). Because of the sensitivity of the blood culture system and the consistency of M avium-intracellulare bacteremia and C neoformans fungemia in patients with the acquired immunodeficiency syndrome, it appears that two blood cultures are sufficient for the detection of most septic episodes caused by these organisms.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Electron cytochemical studies of Cryptococcus neoformans grown on uric acid and related sources of nitrogen.

Cells of Cryptococcus neoformans grown on xanthine or urate as the sole sources of nitrogen produced numerous, single membrane-bound organelles, deemed to be microbodies. Electron images of these structures showed positive cytochemical staining for catalase and alpha-hydroxy acid oxidase, known marker enzyme activities for microbodies. Microbodies in xanthine and urate-grown cells were cytochemically reactive for the presence of the hydrogen peroxide-producing xanthine and urate oxidases. Molybdenum and phosphorus (elements associated with the cofactor common to nitrogen scavenging enzymes) were detected in the substrate-induced microbodies by X-ray dispersive microanalysis. The single limiting membrane of the substrate-induced microbody was stained by a modified Gomori reaction for the presence of alkaline phosphatase, thereby suggesting the participation of this enzymic activity in the events associated with microbody chemistry.

Alkaline Phosphatase↗
PubMedDate not supplied

[Cryptococcosis. A study of 9 strains of Cryptococcus neoformans isolated from immunodeficient patients].

Five strains of Cryptococcus neoformans isolated from the cerebro-spinal fluid and 4 from the blood of AIDS patients, were studied. Although morphologically identical, they differed in the auxanographic pattern. All strains were pathogenic for mice by intracerebral route. Six isolates were sensitive and the other three resistant to 5-fluorocytosine. All strains were sensitive to the other antifungal tested: nystatin, amphotericin B, clotrimazole, miconazole, econazole and ketoconazole.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Characteristics of free water distribution in the cytoplasm of cryotolerant cells of Cryptococcus laurentii].

The resistance to freezing-thawing was studied with Cryptococcus laurentii cultivated at a near-zero plus temperatures in a minimal or a rich medium. At the transition into the stationary phase, the resistance of the cells to freezing increased 20 times in the culture grown in the minimal medium and 8 times in the culture grown in the rich medium. Free water localization in the cell cytoplasm was determined by electron microscopy. In yeast cells with the maximal cryotolerance, free water was found mainly between glycogen granules. The authors discuss the role of glycogen as of a possible factor making the cells resistant to low temperatures.

Cold Temperature↗
PubMed1966

Cryptococcus neoformans in pigeon feces in San Francisco.

Typical Cryptococcus neoformans was isolated from one of 10 specimens of pigeon feces collected in downtown San Francisco. This isolation from a small sample suggests considerable prevalence of this important pathogen and tends to confirm that it is ubiquitous.

Animals↗
PubMed1983

Antibody-dependent leukocyte killing of Cryptococcus neoformans.

Cryptococcus neoformans is an encapsulated, yeast-like fungus which is pathogenic for man. The role of various facets of the immune response which prevent disseminated disease in most normal hosts is unclear. A chromium-release assay was developed using radiolabeled cryptococci to reexamine antibody-dependent cell-mediated killing of this fungus. For a small capsule strain this assay served as a qualitative measure of effector cell function and was correlated with an assay of lethal injury to the organism. Polymorphonuclear leukocytes rather than mononuclear cells were the most active effector cells, causing significant chromium release from the fungus at effector-to-target ratios as low as 3:1. Polymorphonuclear leukocytes and mononuclear cells from a patient with chronic granulomatous disease showed minimal antibody-dependent cell-mediated chromium release suggesting that the final fungicidal pathway may be similar in antibody-dependent and antibody-independent leukocyte killing of this organism.

Animals↗
PubMed1984

Effects of diethylstilbestrol and cyclophosphamide on the pathogenesis of experimental Cryptococcus neoformans infections.

Treatment of mice with a single dose of cyclophosphamide 24 h before challenge with Cryptococcus neoformans increased host survival, whereas treatment with 10 daily exposures of cyclophosphamide, starting 2 days before challenge, markedly reduced survival in mice challenged on the second day of drug treatment. Treatment with 14 daily exposures of diethylstilbestrol before challenge with C. neoformans did not markedly affect host survival. A correlation was sought between the distribution of radiolabeled C. neoformans and host survival. Radiolabeled C. neoformans administered intravenously was cleared rapidly from the blood of naive mice and accumulated in the lungs, liver and kidney within 1 h. The radiolabeled yeasts were subsequently cleared from the lungs. The distribution of radiolabeled C. neoformans among organs was generally the same in control mice and mice treated with diethylstilbestrol of various cyclophosphamide regimens after 3 or 24 h. The distribution of C. neoformans measured as colony forming units was generally in agreement with results from radioactivity measurements for animals sacrificed 3 or 24 h after challenge. One week after challenge, C. neoformans colonies were grown from the brain, liver and kidneys. C. neoformans was found in the brain within 1 h after i.v. challenge, suggesting that the central nervous system disease in mice challenged i.v. resulted from a primary infection of the brain.

Animals↗
PubMed1984

Cryptococcus neoformans in fecal matter of birds kept in cages--Control of Cr. neoformans habitats.

The occurrence of cryptococcosis in predamaged persons in whom the fecal matter of caged birds had been suspected as the source of infection has led to the present investigation. In the excreta of only four out of a total of 142 bird species kept by the Berlin Zoological Gardens, Cryptococcus neoformans could be demonstrated with the aid of Guizotia abyssinica creatinine agar: Twany Frogmouth (Podargus strigoides, G. Eulenschwalm); Palm Cockatoo (Probosciger aterrimus, G. Arakakadu); Military Macaw (Ara militaris, G. Soldatenara); Gray Parrot (Psittacus erithacus, G. Graupapagei). The importance of the fecal matter from caged birds for the epidemiology of cryptococcosis is pointed out. It is recommended to perform a mycological control of pet shops and zoological gardens to prevent the infection of susceptible persons.

Animals↗
PubMedDate not supplied

[Determination of lysine amidase and alpha-aminocaprolactam hydrolase activities in cell-free extracts of Cryptococcus sp].

he methods for detecting two activities, i. e. lysine amidase and alpha-aminocaprolactam hydrolase ones, in crude extracts of Cryptococcus sp. are described. The method for registering lysine amidase activity is based on the ability of Cu(II) complex to absorb at 230 nm. The products of lysine and alpha-aminocaprolactam interactions with o-phthalaldehyde in the presence of mercaptoethanol possess different molar absorption at 340 nm. This fact was used for detecting alpha-aminocaprolactam hydrolase activity. The main merit of the methods is the possibility to register the data on the course of the reaction without preliminary chromatographic separation of the reaction products and reactants. The methods proposed do not require expensive enzymes, such as lysine decarboxylase and lysine-alpha-ketoglutarate-epsilon-aminotransferase, which are used for the quantitative estimation of lysine.

Amidohydrolases↗
PubMed1983

Preliminary study of the pectolytic activity of Cryptococcus albidus var. albidus.

A preliminary study was done on the pectolytic activity of Cryptococcus albidus var. albidus. Cell-free culture broths of six strains of this yeast species were shown to degrade pectin hydrolytically by means of a polygalacturonase-pectinmethylesterase system. Neither pectin nor pectate lyase activities were detected.

Carboxylic Ester Hydrolases↗