title: Influence of capsule size on the in vitro activity of antifungal agents against clinical Cryptococcus neoformans var. grubii strains.
abstract: Cryptococcosis causes disseminated disease in AIDS patients. In contrast to what occurs in laboratory conditions, a large capsule is produced by Cryptococcus neoformans in vivo during infection. The aim of this study was to compare the in vitro activity of different antifungal agents against 34 clinical isolates of C. neoformans var. grubii without or with capsule induction (CLSI, CLSI-C, respectively), following the CLSI M27A3 document. Capsule induction was obtained by addition of NaHCO(3) and incubation with CO(2). The geometric means of the MICs, in µg ml(-1), for CLSI and CLSI-C cultures, respectively, were 1.9 and 9.8 for fluconazole; 0.04 and 0.08 for itraconazole; 0.04 and 0.05 for voriconazole; 0.16 and 0.38 for amphotericin B; and 1.6 and 5.6 for 5-flucytosine. Thus fluconazole showed the highest MICs after capsule induction. Determination of antifungal activity after capsule induction may be clinically relevant and could be used to evaluate the correlation between in vitro results and clinical outcome.
authors.affiliation: Unidad de Parasitología, Micología, Hospital Ramos Mejía, Buenos Aires, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnológicas (CONICET), Buenos Aires, Argentina.
authors.forename: Roxana G
authors.initials: RG
authors.lastname: Vitale
authors.affiliation: División de Análisis Clínicos Sector Biología Molecular, Hospital J.M. Ramos Mejía, Buenos Aires, Argentina.
authors.forename: Veronica
authors.initials: V
authors.lastname: Pascuccelli
authors.affiliation: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.|Unidad de Parasitología, Micología, Hospital Ramos Mejía, Buenos Aires, Argentina.
authors.forename: Javier
authors.initials: J
authors.lastname: Afeltra
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000378:metabolism; D003453:Cryptococcosis / Q000382:microbiology; D003455:Cryptococcus neoformans / Q000166:cytology* / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D017693:Sodium Bicarbonate / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate