Susceptibility testing of Candida albicans isolated from oropharyngeal mucosa of HIV(+) patients to fluconazole, amphotericin B and Caspofungin. killing kinetics of caspofungin and amphotericin B against fluconazole resistant and susceptible isolates.

A clear understanding of the pharmacodynamic properties of antifungal agents is important for the adequate treatment of fungal infections like candidiasis. For certain antifungal agents, the determination of Minimal Fungicidal Concentration (MFC) and time kill curve could be clinically more relevant than the determination of the Minimal Inhibitory Concentration (MIC). In this study, MIC and MFC to fluconazole, amphotericin B and caspofungin against C. albicans isolates and the killing patterns obtained with caspofungin and amphotericin B against susceptible and resistant strains to fluconazole were determined. The results of MICs showed that all C. albicans isolates were highly susceptible to amphotericin B, but two isolates were fluconazole resistant. The comparative analysis between MIC and MFC showed that MFC of fluconazole was fourfold higher than MIC in 41.9% of the C. albicans isolates. Same values of MFC and MIC of amphotericin B and caspofungin were found for 71% of the isolates. Correlation between time kill curves and MFC of amphotericin B and caspofungin against all 4 isolates tested was observed. The caspofungin killing effect was more evident at MFC in 6 hours of incubation than at MIC in this time, suggesting dependence of concentration. The similarity of results of time-kill curve and MFC values indicate that determination of MFC is an alternative for the detection of the fungicidal activity of these drugs.

Antifungal activities of azole agents against the Malassezia species.

In this paper, we identified 95 Malassezia isolates by morphological and biochemical criteria and assessed the in vitro activity of fluconazole, itraconazole, ketoconazole and voriconazole by broth microdilution against these species using slightly modified Leeming-Notman medium. The Malassezia isolates were identified as M. furfur (74), M. sympodialis (11), M. obtusa (8) and M. globosa (2). The modified Leeming-Notman medium used for susceptibility testing allowed good growth of Malassezia spp. Visual reading of the minimal inhibitory concentration (MIC) was readily achieved until Day 5 of incubation at 32 degrees C. Although high MIC values of 16 microg/mL for fluconazole were observed in 9.5% of Malassezia isolates, in general these microorganisms were susceptible to all drugs studied. Interestingly, one M. globosa isolate showed high MIC values for voriconazole, itraconazole and fluconazole. For the 95 strains, the MIC ranges were <0.03-4 microg/mL for ketoconazole, <0.03 to >16 microg/mL for voriconazole, <0.125 to >64 microg/mL for fluconazole and <0.03-16 microg/mL for itraconazole. In summary, the good reproducibility and visual readings obtained using modified Leeming-Notman medium suggest that this medium should be proposed for antifungal testing of drugs against Malassezia spp.

Species distribution and antifungal susceptibility profile of oral candida isolates from HIV-infected patients in the antiretroviral therapy era.

In this study, we investigated the yeasts colonization of genus Candida, including C. dubliniensis, isolated of HIV-infected patients oral cavities and we accessed in vitro susceptibility pattern of the Candida isolates to four antifungal agents. Out of 99 patients investigated, 62 (62.6%) were colonized with yeasts. C. albicans was the prevailing species (50%). C. dubliniensis isolates were not recovered in our study. We verified that 8.1% of the yeasts isolated were resistant to fluconazole, 8.1% to itraconazole and 3.2% to voriconazole. The isolates demonstrated very low voriconazole MICs, in which 79% (49/62) presented values of 0.015 mug/ml. All Candida isolates were susceptible to amphotericin B. The results reported here showed that although C. albicans continues to be present in one-half of oral Candida carriage of HIV-infected patients, Candida non-albicans species are increasing among these patients. Besides, the findings of resistant isolates endorse the role of antifungal susceptibility testing whenever antifungal treatment with azoles is planned.

[Identification of Malassezia species in patients with pityriasis versicolor in Goiânia-GO]. / Identificação de espécies de Malassezia em pacientes com pitiríase versicolor em Goiânia-GO.

The objectives of this study were to investigate the frequency of pityriasis versicolor occurrence and to identify yeasts of the genus Malassezia in patients at the mycology laboratory of the Federal University of Goiás, in Goiânia, State of Goiás. Ninety-five cases of pityriasis versicolor were diagnosed, and four species of Malassezia were identified: Malassezia furfur, Malassezia sympodialis, Malassezia globosa and Malassezia obtusa.