In vitro susceptibility of isolates of Sporothrix schenckii to amphotericin B, itraconazole, and terbinafine: comparison of yeast and mycelial forms.
Forty-three clinical isolates of Sporothrix schenckii derived from humans and animals were evaluated in vitro for their susceptibility to amphotericin B, itraconazole, and terbinafine. MICs were determined by the method of micro dilution in liquid media, using protocols M27-A2 for the yeast form and M38-A for the mycelial form, both standardized by the Clinical Laboratory Standards Institute. In general, higher MICs were found for the mycelial form (intervals of up to two dilutions). In the case of amphotericin B, a significant difference in activity was observed, with higher values (p<0.05) found for the mycelial form. MICs for itraconazole and terbinafine were similar for both yeast and mycelial forms but slightly higher for mycelia. Although data presented here indicate different levels of susceptibility when both growth forms were compared, indicating an intrinsic difference between them, it is still difficult to draw a consensus as to which form correlates better with clinical findings. More studies are necessary to determine the criteria for in vitro tests that will lead to efficient therapeutic choices.
Kohler
Lidiane Meire
LM
Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Brazil. lidikohler@hotmail.com
Soares
Betânia Maria
BM
de Assis Santos
Daniel
D
Da Silva Barros
Maria Elisabete
ME
Hamdan
Júnia Soares
JS
D000666:Amphotericin B / Q000494:pharmacology*; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D002415:Cats; D004285:Dogs; D006736:Horses; D006801:Humans; D017964:Itraconazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development; D009281:Naphthalenes / Q000494:pharmacology*; D013175:Sporothrix / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D000077291:Terbinafine; D015003:Yeasts / Q000187:drug effects / Q000254:growth & development
D000935:Antifungal Agents; D009281:Naphthalenes; D017964:Itraconazole; D000666:Amphotericin B; D000077291:Terbinafine