In vitro susceptibility of Paracoccidioides brasiliensis yeast form to antifungal agents Susceptibilidad in vitro de la forma levaduriforme de Paracoccidioides brasiliensis a los agentes antifungicos

• Main Authors: Angela Restrepo, Catalina de Bedoutand Angela M. Tabares
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1984
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doaj.org/article/5b451d5e462941c0b230c58b2d35a3c7

A study was conducted to determine the susceptibility of P. brasiliensis yeast form to amphotericin B (A), ketoconazole (K), 5-fluorocytosine (5-FC) and rifampin (R). The three isolates tested produced minimal inhibitory concentrations (MICs) (mcg/ml) in the following range: A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 and R: 40-80. The minimal fungicidal concentrations (MFC) were several times higher than the corresponding MICs. Precise MFC for 5-FC were not obtained (> 500 mcg/ml). Combination of K plus A proved synergic, with the fractional inhibitory concentration (FIC) indices revealing synergy when the drugs were combined at the 1 to 1 and 1 to 5 MIC ratios. R (40 mcg/ml) appeared to antagonize K. These results indicate promise for the combined use of K plus A as a therapeutical regimen. Se realizó un estudio con el objeto de determinar la susceptibilidad de la fase levaduri-forme del P. brasiliensis a la Anfotericina B (A), el Ketoconazol (K), la 5-fluorocitosina (5-FC) y la rifampicina. Las 3 cepas estudiadas tuvieron las siguientes concentraciones inhibitorias mínimas (MIC) (mcg/ml) A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 y R: 40-80. Las concentraciones fungicidas mínimas (MFC) resultaron más altas que las MICs correspondientes. En el caso de la 5-FC no se obtuvo una cifra MFC precisa (> 500 mcg/ml). La combinación de K más A mostró ser sinérgica al combinarse las drogas en relación 1:1 y 1:5 de los MICs respectivos. R (40 mcg/ml) se mostró antagonista del K. Los resultados indican que la combinación A + K pudiera constituir un adecuado régimen terapéutico en ciertos pacientes.