Usefulness of matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry for identifying clinical Trichosporon isolates.

Trichosporon spp. have recently emerged as significant human pathogens. Identification of these species is important, both for epidemiological purposes and for therapeutic management, but conventional identification based on biochemical traits is hindered by the lack of updates to the species databases provided by the different commercial systems. In this study, 93 strains, or isolates, belonging to 16 Trichosporon species were subjected to both molecular identification using IGS1 gene sequencing and matrix-assisted laser desorption ionisation-time-of-flight (MALDI-TOF) analysis. Our results confirmed the limits of biochemical systems for identifying Trichosporon species, because only 27 (36%) of the isolates were correctly identified using them. Different protein extraction procedures were evaluated, revealing that incubation for 30 min with 70% formic acid yields the spectra with the highest scores. Among the six different reference spectra databases that were tested, a specific one composed of 18 reference strains plus seven clinical isolates allowed the correct identification of 67 of the 68 clinical isolates (98.5%). Although until recently it has been less widely applied to the basidiomycetous fungi, MALDI-TOF appears to be a valuable tool for identifying clinical Trichosporon isolates at the species level.

Dual candidemia detected by nested polymerase chain reaction in two critically ill children.

The use of improved microbiological procedures associated with molecular techniques has increased the identification of Candida bloodstream infections, even if the isolation of more than one species by culture methods remains uncommon. We report the cases of two children presenting with severe gastrointestinal disorders and other risk factors that contribute to Candida infections. In the first patient, C. albicans DNA was initially detected by a nested-amplification and C. tropicalis was found later during hospitalization, while blood cultures were persistently negative. In the second child, there was amplification of C. albicans and C. glabrata DNA in the same samples, but blood cultures yielded only C. albicans. Both patients received antifungal therapy but had unfavorable outcomes. These two cases illustrate that PCR was more successful than culture methods in detecting Candida in the bloodstream of high risk children, and was also able to detect the presence of more than one species in the same patient that might impact therapy when the fungi are resistant to azole compounds.

Paracoccidioidomycosis: an epidemiologic survey in a pediatric population from the Brazilian Amazon using skin tests.

Since Paracoccidioides brasiliensis and Histoplasma capsulatum are known to be present in similar environments, there have been many epidemiologic investigations regarding the prevalences of these two organisms. However, cross-reactivity can occur in paracoccidioidin and histoplasmin skin tests, and this usually results in the overestimation of the prevalence of P. brasiliensis. The prevalence of infection with P. brasiliensis was evaluated in a cross-sectional study of 298 asymptomatic school children in the Brazilian Amazon region (Mato Grosso State). In this investigation, the reactivity of children to two different P. brasiliensis antigen preparations, paracoccidioidin and a purified 43-kD glycoprotein (gp43), was compared with or without the co-administration of histoplasmin. In the group of individuals receiving paracoccidioidin who had a positive histoplasmin skin test result, the prevalence of exposure to P. brasiliensis was 44% (16 of 36). This reactivity to P. brasiliensis was significantly higher than that observed in other groups, which ranged from 4% to 6% (P < 5 x 10(-4) for each). Overall prevalence was 4.6% (95% confidence interval = 2.5-7.7%). These data suggest that gp43 provides a better estimate of exposure to P. brasiliensis when the co-administration of histoplasmin is desired.

Randomized trial with itraconazole, ketoconazole and sulfadiazine in paracoccidioidomycosis.

Forty-two patients with active paracoccidioidomycosis were randomized to receive itraconazole (50-100 mg d(-1)), ketoconazole (200-400 mg d(-1)) or sulfadiazine (100-150 mg kg d(-1) up to 6 g d(-1)) for 4-6 months, followed by slow release sulfa until negativity of serological tests. All 14 patients in itraconazole and sulfadiazine groups and 13 in the ketoconazole group showed an adequate clinical response to the chemotherapy. One patient in the latter group showed treatment failure according to clinical and mycological criteria. The test of the hypothesis that the drugs reduced antibody levels up to ten months of treatment showed a p value equal to 0.0001 for itraconazole, 0.017 for ketoconazole and 0.0012 for sulfadiazine; this reduction was similar for the three groups. In this first randomized study for the treatment of paracoccidioidomycosis we could not show superiority of any one regimen over the others in the clinical and serological responses of patients with the moderately severe form of the disease.

The sensitivity, specificity and efficiency values of some serological tests used in the diagnosis of paracoccidioidomycosis

O presente trabalho avalia a sensibilidade, especificidade e eficiencia da imunodifusao dupla (ID), contraimunoeletroforese (CIE), reacao de fixacao de complemento (FC) e imunofluorescencia indireta (IFI) no diagnostico da paracoccidioidomicose. Os pacientes portadores da micose, virgens de tratamento, tiveram o diagnostico confirmado por exame micologico e/ou histopatologico. Utilizou-se como antigenos o filtrado de cultura da fase leveduriforme do Paracoccidioides brasiliensis para os testes de ID, CIE, FC e suspensao de celulas leveduriformes de "pool" de cepas do mesmo fungo para o teste de IFI. O estudo foi realizado em 4 grupos de individuos: 46 com paracoccidioidomicose ativa (sem tratamento), 22 com outras micoses profundas, 30 com outras doencas infecciosas (tuberculose e leishmaniose tegumentar) e 47 controles normais. Os valores de sensibilidade, especificidade e eficiencia foram obtidos de acordo com a metodologia utilizada por GALEN & GAMBINO (1975). Os resultados revelaram que os testes de precipitacao em gel de agar e agarose, representados pela ID e CIE foram os melhores, apresentando maior sensibilidade (91,3 por cento e 95,6 por cento, respectivamente), maxima especificidade (100 por cento) e os maiores valores de eficiencia quando comparados a FC e IFI...