RESUMO
Introduction. Cryptococcus species are pathogens commonly associated with cases of meningoencephalitis in individuals who are immunosuppressed due to AIDS.Aim. The aim was to evaluate the effects of the antiretroviral darunavir alone or associated with fluconazole, 5-flucytosine and amphotericin B against planktonic cells and biofilms of Cryptococcus species.Methodology. Susceptibility testing of darunavir and the common antifungals against 12 members of the Cryptococcus neoformans/Cryptococcus gattii species complex was evaluated by broth microdilution. The interaction between darunavir and antifungals against planktonic cells was tested by a checkerboard assay. The effects of darunavir against biofilm metabolic activity and biomass were evaluated by the XTT reduction assay and crystal violet staining, respectively.Results. Darunavir combined with amphotericin B showed a synergistic interaction against planktonic cells. No antagonistic interaction was observed between darunavir and the antifungals used. All Cryptococcus species strains were strong biofilm producers. Darunavir alone reduced biofilm metabolic activity and biomass when added during and after biofilm formation (P<0.05). The combination of darunavir with antifungals caused a significant reduction in biofilm metabolic activity and biomass when compared to darunavir alone (P<0.05).Conclusion. Darunavir presents antifungal activity against planktonic cells of Cryptococcus species and synergism with amphotericin B. In addition, darunavir led to reduced biofilm formation and showed activity against mature biofilms of Cryptococcus species. Activity of the antifungals against mature biofilms was enhanced in the presence of darunavir.
Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Cryptococcus gattii/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Darunavir/farmacologia , Anfotericina B/farmacologia , Células Cultivadas , Fluconazol/farmacologia , Testes de Sensibilidade Microbiana/métodos , Plâncton/microbiologiaRESUMO
INTRODUCTION: Fungi of the genus Cryptococcus are cosmopolitan and may be agents of opportunistic mycoses in immunocompromised and sometimes immunocompetent individuals. Cryptococcus species are frequently isolated from trees and bird excreta in the environment and infection occurs by inhalation of propagules dispersed in the air. The aim was to investigate Cryptococcus species in bird excreta and tree hollows located in a university hospital area and in an academic area of a university campus. METHODOLOGY: A total of 40 samples of bird excreta and 41 samples of tree hollows were collected. The identification of the isolates was done by classical methodology and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: Twenty (62.5%) isolates of Cryptococcus were found in bird excreta and 12 (37.5%) in tree hollows. C. laurentii (currently Papiliotrema laurentii) was the most frequent species in both samples, being found in 5 samples of excreta and in 8 tree hollows. The diversity of species found in excreta (C. laurentii, C. albidus [currently Naganishia albida], C. liquefaciens [currently N. liquefaciens], C. friedmanii [currently N. friedmannii] and others) was higher than in tree hollows (C. laurentii, C. flavescens [currently Papiliotrema flavescens], and other yeasts). CONCLUSION: Many Cryptococcus species were isolated from excreta and tree hollows, and this fact is important for understanding the environmental epidemiology of those emerging pathogens for public health, as a way to implement surveillance actions and control of cryptococcosis.
Assuntos
Cryptococcus/classificação , Cryptococcus/isolamento & purificação , Microbiologia Ambiental , Fezes/microbiologia , Centros Médicos Acadêmicos , Animais , Aves , Hospitais UniversitáriosRESUMO
UNLABELLED: Cryptococcosis, a fungal infection that affects both immunocompromised and immunocompetent individuals, contributes to increasing indices of mortality and morbidity. The development of resistance by Cryptococcus spp., the limited number of commercial antifungal drugs and the various side effects of these drugs cause the treatment of cryptococcosis to be a challenge. The in vitro anticryptococcal activity of nine hydroxyaldimines was evaluated against 24 strains of Cryptococcus spp. Antifungal susceptibility was evaluated using a broth microdilution assay following the Clinical and Laboratory Standards Institute guidelines, using fluconazole as a positive control. Parameters such as the minimum inhibitory concentration and the minimum fungicidal concentration (MIC and MFC, respectively) were also determined. Antiproliferative activity on the normal cell line VERO was assessed 48 h post-compound exposure to determine the selectivity index (SI) of the hydroxyaldimines and fluconazole. All hydroxyaldimines were active against Cryptococcus spp. strains. Compounds 3A9 and 3B7 were the most potent against the Cryptococcus gattii and Cryptococcus neoformans strains. Selectivity indices also revealed that 3B10, 3C3, 3D3 and 3D9 are good candidates for in vivo studies. The in vitro anticryptococcal activity of hydroxyaldimines against various strains of C. gattii and C. neoformans indicates the potential of this class of molecules as lead compound for the development of selective and efficient anticryptococcal agents. SIGNIFICANCE AND IMPACT OF THE STUDY: The effectiveness of hydroxyaldimines for inhibition of Cryptococcus spp. growth and their low toxicity against healthy monkey kidney epithelial cells makes them promising lead compounds for the design of new anticryptococcal agents.