Cryptococcus gattii: in vitro susceptibility to the new antifungal albaconazole versus fluconazole and voriconazole.

Minimal inhibitory concentrations (MIC) and minimal fungicidal activity of albaconazole, voriconazole and fluconazole against 55 strains of Cryptococcus gattii, clinically or environmentally isolated in Spain and some Latin American countries, were assessed. By means of the microbroth method (National Committee for Clinical Laboratory Standards; document M27-A2), the geometric mean value for fluconazole was 5.01 microg/ml; however, MIC for 12.7% of isolates ranged from 16 to 32 microg/ml, suggesting increased resistance against fluconazole. Geometric mean values of 0.02 and 0.03 microg/ml for albaconazole and voriconazole, respectively, were found, indicating not only a higher susceptibility to these new azoles but also a better performance of albaconazole (P = 0.003). Minimal fungicidal concentrations were also very low for albaconazole and voriconazole (P<0.001; geometric mean values of 0.023 microg/ml and 0.07 microg/ml, respectively). Both azoles may be good alternatives for the treatment of C. gattii cryptococcosis.

DNA fingerprinting pattern and susceptibility to antifungal drugs in Cryptococcus neoformans variety grubii isolates from Barcelona city and rural environmental samples.

Cryptococcus neoformans var. grubii (serotype A) was isolated from 12 soil samples mixed with pigeon droppings (16.9%) from 71 soil samples in Barcelona and rural areas of Catalonia. C. neoformans was not isolated from indoor dust and Eucalyptus debris. PCR fingerprinting was performed in 22 representative isolates and all of them corresponded to the VNI pattern. Susceptibility testing for the 22 isolates of C. neoformans var. grubii showed that all of them were susceptible to amphotericin B. Three isolates presented MICs (Minimal Inhibitory Concentrations) > or = 1 microg/ml to Itraconazole, five MICs > or = 1 microg/ml to ketoconazole and four were fluconazole resistant, (MICs > or = 64 microg/ml), while three of them were shown to have MICs > or = 1 microg/ml to voriconazole. In spite that all isolates presented the same DNA fingerprinting pattern, the susceptibility to antifungals is very variable. The possibility of acquiring cryptococcosis infection with primarily resistant environment strains is feasible.

[In vitro susceptibility of fungal and yeast clinical isolates to itraconazole and voriconazole]. / Estudio de la sensibilidad in vitro de aislamientos clinicos de mohos y levaduras a itraconazol y voriconazol.

The interest on the in vitro susceptibility to itraconazole has recently increased due the availability of the intravenous formulation. In this study, comparative MICs of this antifungal with voriconazole were carried out in 62 clinical isolates of filamentous fungi and 100 yeasts isolates using the NCCLS microbroth methods described in M38-A and M27-A2 documents. A MIC90 of 0.125 micrograms per ml was observed for itraconazole and voriconazole against Aspergillus fumigatus. Higher susceptibility to itraconazole was found for the filamentous form of Sporotrhix schenckii (p = 0.001). Voriconazole was more effective against Scedosporium apiospermium while Scedosporium prolificans isolates were resistant to both azoles. Some isolates of Rhizopus stolonifer were susceptible to itraconazole and resistant to voriconazole, but without statistical significance. Susceptibility of nine species of Candida was similar for both triazoles used in this study. However, Candida glabrata was more susceptible to voriconazole. Some fluconazole-resistant Candida albicans isolates were susceptible to itraconazole and / or voriconazole. Cryptococcus neoformans was more susceptible to itraconazole than to voriconazole. Itraconazole and voriconazole showed very close in vitro activity against the tested fungal isolated, except against S. schenckii. In spite of this, there were some differences in susceptibility among isolates within the same fungal species.