Effects of amphotericin B on Aspergillus flavus clinical isolates with variable susceptibilities to the polyene in an experimental model of systemic aspergillosis.

Objectives: The aim of the present study was to evaluate the effects of amphotericin B (AMB) on clinical isolates of Aspergillus flavus.

Methods: MICs of both standard AMB and liposomal AMB (L-AMB) were determined using a broth dilution method for seven isolates of A. flavus.

In vitro and in vivo effects of echinocandins against Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis.

Objectives: The aim of the present study was to compare, in vitro and in vivo, the effects of caspofungin, micafungin and anidulafungin against Candida parapsilosis complex isolates.

Methods: In vitro activities of all three echinocandins were assessed against C. parapsilosis sensu stricto (n = 4), Candida orthopsilosis (n = 4) and Candida metapsilosis (n = 3) using broth microdilution susceptibility testing, minimum fungicidal concentration determination and a killing-curve assay, in the absence and in the presence of 50% human serum.

Comparative effects of micafungin, caspofungin, and anidulafungin against a difficult-to-treat fungal opportunistic pathogen, Candida glabrata.

The aim of this study was to compare the in vitro and in vivo activities of micafungin, caspofungin, and anidulafungin against Candida glabrata. The MICs against 28 clinical isolates showed that the overall susceptibilities to caspofungin and to micafungin were not statistically different in the absence of human serum, whereas the isolates were less susceptible to micafungin than to caspofungin in its presence. Minimum fungicidal concentrations, as well as time-kill experiments, showed that caspofungin was more active than anidulafungin, while micafungin was superior to either caspofungin or anidulafungin without serum; its addition rendered caspofungin and micafungin equally effective.

Heterozygosis and pathogenicity of Cryptococcus neoformans AD-hybrid isolates.

Nineteen Cryptococcus neoformans AD-hybrid isolates were investigated to assess whether hybrid genomic background could affect virulence in a mouse model. The level of heterozygosity of each strain was analyzed using primers specific for allele A and D of 15 polymorphic genes. Virulence was tested in a mouse model of systemic infection by measuring time of survival.

In vitro and in vivo activities of posaconazole against zygomycetes with various degrees of susceptibility.

Objectives: We analysed the in vitro and in vivo effects of posaconazole and amphotericin B against three clinical isolates of zygomycetes: Lichtheimia corymbifera, F1; and Rhizopus oryzae, F5 and F6.

Methods: In vitro activities of both drugs were assessed by determining MICs, minimum fungicidal concentrations (MFCs) and fungal damage measured by the XTT assay against either the spores or the hyphal forms. Additionally, the survival curves of neutropenic mice systemically infected with the zygomycete isolates were used as the marker of antifungal response to amphotericin B (1 mg/kg/day) or posaconazole (2.