Visible DNA microarray and loop-mediated isothermal amplification (LAMP) for the identification of Cryptococcus species recovered from culture medium and cerebrospinal fluid of patients with meningitis.

Cryptococcal meningitis affects normal hosts and immunocompromised patients exhibiting high mortality rates. The objective of this study was to design two molecular assays, visible microarray platforms and loop-mediated isothermal amplification (LAMP), to identify Cryptococcus spp. and the species neoformans and gattii from the cerebral spinal fluid (CSF). To identify Cryptococcus and the two species, we designed two microarrays DNA platforms based on the internal transcribed spacer (ITS) region and CAP59 gene and LAMP assays specific for Cryptococcus species. The assays were tested using CSF from patients with cryptococcal meningitis. CSF from patients with cryptococcal meningitis was cultured in Sabouraud culture medium, and the Cryptococcus spp. grown in the culture medium were also tested for LAMP and microarray platforms. The results were compared to DNA sequencing of the same genetic regions. A total of 133 CSF samples were studied. Eleven CSFs were positive for Cryptococcus (9 C. neoformans and 2 C. gattii), 15 were positive for bacteria, and 107 were negative. The CAP59 platform correctly identified 73% of the CSF samples, while the ITS platform identified 45.5%. CAP59 platform correctly identified 100% of the Cryptococcus isolates, and ITS platform identified 70%. The two sets of LAMP primers correctly identified 100% of the Cryptococcus isolates. However, for CSF samples, the amplification occurred only in 55.5% of C. neoformans. The methodologies were reliable in the identification of Cryptococcus species, mainly for isolates from culture medium, and they might be applied as adjunctive tests to identify Cryptococcus species.

Visible DNA microarray and loop-mediated isothermal amplification (LAMP) for the identification of Cryptococcus species recovered from culture medium and cerebrospinal fluid of patients with meningitis

Cryptococcal meningitis affects normal hosts and immunocompromised patients exhibiting high mortality rates. The objective of this study was to design two molecular assays, visible microarray platforms and loop-mediated isothermal amplification (LAMP), to identify Cryptococcus spp. and the species neoformans and gattii from the cerebral spinal fluid (CSF). To identify Cryptococcus and the two species, we designed two microarrays DNA platforms based on the internal transcribed spacer (ITS) region and CAP59 gene and LAMP assays specific for Cryptococcus species. The assays were tested using CSF from patients with cryptococcal meningitis. CSF from patients with cryptococcal meningitis was cultured in Sabouraud culture medium, and the Cryptococcus spp. grown in the culture medium were also tested for LAMP and microarray platforms. The results were compared to DNA sequencing of the same genetic regions. A total of 133 CSF samples were studied. Eleven CSFs were positive for Cryptococcus (9 C. neoformans and 2 C. gattii), 15 were positive for bacteria, and 107 were negative. The CAP59 platform correctly identified 73% of the CSF samples, while the ITS platform identified 45.5%. CAP59 platform correctly identified 100% of the Cryptococcus isolates, and ITS platform identified 70%. The two sets of LAMP primers correctly identified 100% of the Cryptococcus isolates. However, for CSF samples, the amplification occurred only in 55.5% of C. neoformans. The methodologies were reliable in the identification of Cryptococcus species, mainly for isolates from culture medium, and they might be applied as adjunctive tests to identify Cryptococcus species.

Severe Paracoccidioidomycosis in a 14-Year-Old Boy.

Paracoccidioidomycosis (PCM) is the most important systemic mycoses in Latin America. We describe a severe case of paracoccidioidomycosis in a 14-year-old boy, with a rapid disease progression. The fungal strain was isolated and inoculated into a T and/or B cell immunocompromised mice, which revealed a highly virulent strain. The case report presented herein emphasizes the importance of considering PCM in the differential diagnosis of patients with other infectious diseases in endemic areas and highlights a novel isolate.

Expression of activation and cytotoxic molecules by peripheral blood lymphocytes of patients with paracoccidioidomycosis.

In a previous study, we reported an increased number of T CD8(+) cells in the bronchoalveolar lavage (BAL) of patients with pulmonary paracoccidioidomycosis, suggesting a role for these cells in the local immune response. The aims of this study were to verify, by flow cytometry, the activation state, as well as the production of cytotoxic molecules by peripheral blood lymphocytes (CD8(+) and CD4(+)). Specimens were obtained from patients with paracoccidioidomycosis (PCM), individuals with PCM-infection, i.e., healthy individuals with demonstrated strong cellular response against the fungus (PI) and controls, with studies conducted both ex-vivo and in vitro, after stimulation with Paracoccidioides brasiliensis yeast cells. The ex-vivo analysis demonstrated that PCM patients presented a lower frequency of granzyme A, B and perforin-positive cells, as compared to individuals with PCM infection (PI). P. brasiliensis stimulation led to a discrete increase in CD69(+) cells and a reduction in cytotoxic granule expression in all groups. The addition of IL-15 induced an increase in the frequency of CD69(+) cells only in PI individuals and controls. The effect of IL-15 on granzyme A and B expression was low, but a higher frequency of CD8(+) perforin(+) was detected in PI individuals than in patients with active PCM. IL-15Ralpha expression was lower in CD4(+) T cells from patients, in relation to the PI group. Furthermore, low levels of granulysin were detected in sera from PCM patients, but a tendency for an increase in these levels was observed after antifungal therapy. Taken together, these results indicate that lymphocytes from PCM patients are poorly activated, express low levels of IL-15Ralpha and produce basal levels of cytotoxic granules. These findings may account for the defective cytotoxic activity in patients and, consequently, a low capacity to kill the fungus.

Diagnosis of candidemia by polymerase chain reaction and blood culture: prospective study in a high-risk population and identification of variables associated with development of candidemia.

The diagnosis of candidemia is important for prompt initiation of antifungal therapy. Two hundred twenty-five patients at high risk for candidemia who had blood cultures drawn and were hospitalized for more than 15 days were followed-up prospectively over a 2-year period. Polymerase chain reaction (PCR) and whole-blood cultures monitored by the automated BactAlert system (Organon Teknika, Durham, NC, USA) were used to detect candidemia in all patients hospitalized in high-risk areas for more than 15 days. DNA was extracted and amplified using ITS5 and ITS4 base pair primers, and the PCR products were sequenced for identification of Candida spp. A blood culture positive for Candida was considered the gold standard for diagnosis of candidemia. Variables associated with the development of candidemia diagnosed by positive blood culture were also evaluated in the patients. The overall mortality rate was 26.1%. Mortality in candidemic patients was 41.9% and in noncandidemic patients 22.5% (p = 0.009). PCR sensitivity and specificity were 72.1 and 91.2%, respectively. Positive and negative predictive values were 65.9 and 93.2%, respectively. The logistic regression of the multivariate analysis showed that parenteral nutrition (p < 0.0001), fever (p = 0.01), neutropenia (p = 0.04), and an indwelling urinary catheter (p = 0.02) were significant variables associated with the development of candidemia. The PCR technique in conjunction with DNA sequencing was a helpful tool in the diagnosis of candidemia.

Evaluation of Fusarium solani hyphae and conidia susceptibility to amphotericin B and itraconazole: study of a clinical case.

Fusarium species are hyaline moulds belonging to the hyalohyphomycosis group that are usually found in the soil and plants. This organism has emerged as a cause of disseminated invasive disease. The correlation between in vitro value and clinical efficacy is low and many patients remain unresponsive to treatment despite in vitro susceptibility. We determined growth control for Fusarium solani using the BioCell-Tracer system that measures the growth rate of a single fungal hypha, and the effect of different concentrations of amphotericin B and itraconazole. The MIC for these two drugs was also determined by a broth microdilution technique, using RPMI 1640. Different MICs for amphotericin B were obtained by the two different methods. This paper describes a case of infection due to Fusarium solani in an allogeneic bone marrow transplanted patient, the microbiological diagnostic, antifungal susceptibility tests for conidia and hypha and clinical correlation.

Antifungal susceptibility and pathogenic potential of environmental isolated filamentous fungi compared with colonizing agents in immunocompromised patients.

Infection is a major cause of morbidity and mortality in bone marrow transplant recipients and in patients with hematological malignancies. The source of infection is almost always endogenous flora or the hospital environment. The present study evaluated bone marrow transplant recipients and patients with hematological malignancies colonized and/or infected with filamentous fungi. During 1 year, environmental air samples were also taken from the bone marrow transplant unit by a modification of gravity air-setting plate (GASP) methodology. Fusarium spp. were the most prevalent genus in the fall and Cladosporium spp. in the winter. Clinically isolated strains grew better at 37 degrees C than environmental strains. According to NCCLS M-38P methods, environmental Aspergillus strains showed higher MICs to miconazol and itraconazol, and clinical Fusarium strains were less susceptible to fluconazole.

Respiration, oxidative phosphorylation, and uncoupling protein in Candida albicans

The respiration, membrane potential (Dy), and oxidative phosphorylation of mitochondria in situ were determined in spheroplasts obtained from Candida albicans control strain ATCC 90028 by lyticase treatment. Mitochondria in situ were able to phosphorylate externally added ADP (200 µM) in the presence of 0.05 percent BSA. Mitochondria in situ generated and sustained stable mitochondrial Dy respiring on 5 mM NAD-linked substrates, 5 mM succinate, or 100 µM N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride plus 1 mM ascorbate. Rotenone (4 µM) inhibited respiration by 30 percent and 2 µM antimycin A or myxothiazole and 1 mM cyanide inhibited it by 85 percent. Cyanide-insensitive respiration was partially blocked by 2 mM benzohydroxamic acid, suggesting the presence of an alternative oxidase. Candida albicans mitochondria in situ presented a carboxyatractyloside-insensitive increase of Dy induced by 5 mM ATP and 0.5 percent BSA, and Dy decrease induced by 10 µM linoleic acid, both suggesting the existence of an uncoupling protein. The presence of this protein was subsequently confirmed by immunodetection and respiration experiments with isolated mitochondria. In conclusion, Candida albicans ATCC 90028 possesses an alternative electron transfer chain and alternative oxidase, both absent in animal cells. These pathways can be exceptional targets for the design of new chemotherapeutic agents. Blockage of these respiratory pathways together with inhibition of the uncoupling protein (another potential target for drug design) could lead to increased production of reactive oxygen species, dysfunction of Candida mitochondria, and possibly to oxidative cell death.

Respiration, oxidative phosphorylation, and uncoupling protein in Candida albicans.

The respiration, membrane potential (Deltapsi), and oxidative phosphorylation of mitochondria in situ were determined in spheroplasts obtained from Candida albicans control strain ATCC 90028 by lyticase treatment. Mitochondria in situ were able to phosphorylate externally added ADP (200 microM) in the presence of 0.05% BSA. Mitochondria in situ generated and sustained stable mitochondrial Deltapsi respiring on 5 mM NAD-linked substrates, 5 mM succinate, or 100 microM N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride plus 1 mM ascorbate. Rotenone (4 microM) inhibited respiration by 30% and 2 micro M antimycin A or myxothiazole and 1 mM cyanide inhibited it by 85%. Cyanide-insensitive respiration was partially blocked by 2 mM benzohydroxamic acid, suggesting the presence of an alternative oxidase. Candida albicans mitochondria in situ presented a carboxyatractyloside-insensitive increase of Deltapsi induced by 5 mM ATP and 0.5% BSA, and Deltapsi decrease induced by 10 microM linoleic acid, both suggesting the existence of an uncoupling protein. The presence of this protein was subsequently confirmed by immunodetection and respiration experiments with isolated mitochondria. In conclusion, Candida albicans ATCC 90028 possesses an alternative electron transfer chain and alternative oxidase, both absent in animal cells. These pathways can be exceptional targets for the design of new chemotherapeutic agents. Blockage of these respiratory pathways together with inhibition of the uncoupling protein (another potential target for drug design) could lead to increased production of reactive oxygen species, dysfunction of Candida mitochondria, and possibly to oxidative cell death.

Phaeohyphomycosis caused by Chaetomium globosum in an allogeneic bone marrow transplant recipient.

Bone marrow transplant recipients are highly susceptible to opportunistic fungal infections. This is the report, of the first case of a Chaetomium systemic infection described in Brazil. A 34 year-old patient with chronic myeloid leukemia underwent an allogeneic sibling matched bone marrow transplant. Seven months later, he developed systemic infection with enlargement of the axillary and cervical lymph nodes. Culture of the aspirates from both lymph nodes yielded Chaetomium globosum. The infection was successfully treated with amphotericin B. The increasing population of immunosupressed patients requires a careful microbiologic investigation for uncommon fungal infections.

Respiratory chain network in mitochondria of Candida parapsilosis: ADP/O appraisal of the multiple electron pathways.

In this study we demonstrated that mitochondria of Candida parapsilosis contain a constitutive ubiquinol alternative oxidase (AOX) in addition to a classical respiratory chain (CRC) and a parallel respiratory chain (PAR) both terminating by two different cytochrome c oxidases. The C. parapsilosis AOX is characterized by a fungi-type regulation by GMP (as a stimulator) and linoleic acid (as an inhibitor). Inhibitor screening of the respiratory network by the ADP/O ratio and state 3 respiration determinations showed that (i) oxygen can be reduced by the three terminal oxidases through four paths implying one bypass between CRC and PAR and (ii) the sum of CRC, AOX and PAR capacities is higher than the overall respiration (no additivity) and that their engagement could be progressive according to the redox state of ubiquinone, i.e. first cytochrome pathway, then AOX and finally PAR.

Trichosporon species infection in bone marrow transplanted patients.

Trichosporon species are emerging as opportunistic agents that cause systemic diseases in immunocompromised patients. Patients undergoing bone marrow transplant are submitted to intense and prolonged periods of neutropenia and consequently to several risk factors to fungal infections as the use of broad spectrum antibiotics and invasive devices. Two cases of fungal infections caused by Trichosporon asahii var. asahii and T. inkin in patients with bone marrow transplant are described T. asahii var. asahii was responsible for fungemia and the identification of this microorganism was later performed. T. inkin caused vascular accesses infection and was recovered from an implanted Hickman-Broviac catheter. Both patients were under oral fluconazole prophylaxis. The patient with systemic infection died despite the therapy with amphotericin B and the patient with catheter-related infection recovered from the fungal infection after catheter removal. Difficulties in the identification of this microorganism lead to delays in treatment and post-mortem diagnosis.

First evidence and characterization of an uncoupling protein in fungi kingdom: CpUCP of Candida parapsilosis.

An uncoupling protein (UCP) was identified in mitochondria from Candida parapsilosis (CpUCP), a non-fermentative parasitic yeast. CpUCP was immunodetected using polyclonal antibodies raised against plant UCP. Activity of CpUCP, investigated in mitochondria depleted of free fatty acids, was stimulated by linoleic acid (LA) and inhibited by GTP. Activity of CpUCP enhanced state 4 respiration by decreasing DeltaPsi and lowered the ADP/O ratio. Thus, it was able to divert energy from oxidative phosphorylation. The voltage dependence of electron flux indicated that LA had a pure protonophoretic effect. The discovery of CpUCP proves that UCP-like proteins occur in the four eukaryotic kingdoms: animals, plants, fungi and protists.

New PCR primer pairs specific for Cryptococcus neoformans serotype A or B prepared on the basis of random amplified polymorphic DNA fingerprint pattern analyses.

Thirty-three strains of Cryptococcus neoformans were isolated from clinical specimens, including specimens from AIDS patients in Brazil, and were classified into two serotypes; we detected 31 and 2 strains of serotypes A and B, respectively. Random amplified polymorphic DNA (RAPD) fingerprint pattern analyses of these strains of serotypes A and B showed that the patterns were similar for strains of each serotype when three 10-mer primers were used as the RAPD primers. Comparative studies of the fingerprint patterns of the study isolates with those of the reference strains also showed that the RAPD patterns for strains of each serotype were related and that most of the fingerprint bands existed commonly for all strains of each serotype tested. The common RAPD bands (an approximately 700-bp band for serotype A and an approximately 450-bp band for serotype B) were extracted and the DNA sequences were determined. Using this information, we prepared two and one PCR primer pairs which were expected to be specific for C. neoformans serotypes A and B, respectively. Use of each PCR primer combination thus prepared for serotype A or B was 100% successful in identifying the respective C. neoformans serotypes, including the 33 clinical isolates tested in the present study. Among these combinations, one for serotype A was found to amplify DNA from C. neoformans serotype B as well as serotype A. Serotype B-specific PCR primer pairs amplified DNA from not only serotype B strains but also from serotype C strains. The usefulness of other serotype-specific PCR primers for clinical C. neoformans isolates is discussed.

Candida parapsilosis fungemia associated with implantable and semi-implantable central venous catheters and the hands of healthcare workers.

A cluster of six cases of fungemia among hematology, bone marrow transplant, and oncology patients was investigated in a case-control study (18 controls). The use of implantable and semi-implantable central venous catheters was significantly associated with cases (p = 0.016). The hands of three healthcare workers (HCWs) were positive for Candida parapsilosis. Electrophoretic karyotyping showed two profiles among patients and HCWs, and five among six unrelated strains. The profiles of two HCWs matched the ones of the patients they had handled. The patients' strains were moderate or strong slime producers, whereas none of the HCWs' were strong producers. In conclusion, our results indicated the occurrence of an outbreak C. parapsilosis fungemia related to long-term central venous catheters in which the hands of HCWs were implicated. The amount of slime production might be associated with the pathogenicity of the strains.