Synergysm of voriconazole or itraconazole with other antifungal agents against species of Fusarium

Antecedentes: Las micosis causadas por Fusarium son difíciles de tratar porque tanto in vivo como in vitro estos hongos muestran resistencia a casi todos los fármacos antimicóticos disponibles, lo que explica las altas tasas de mortalidad. Una tentativa de resolver la resistencia fúngica es combinar los fármacos antifúngicos, en especial los preparados con mecanismos de acción diferentes. Objetivos: Valorar las interacciones in vitro de la combinación de voriconazol o itraconazol con otros fármacos antimicóticos frente a 32 aislamientos de Fusarium spp: Fusarium chlamydosporum, Fusarium oxysporum, Fusarium proliferatum y Fusarium solani. Métodos: Las interacciones farmacológicas se valoraron con el método de microdilución en tablero de ajedrez, que también incluyó la determinación de la concentración inhibitoria mínima de cada fármaco por separado de acuerdo con el documento M38-A2, 2008, del Clinical and Laboratory Standards Institute. Resultados: Las mejores combinaciones fueron voriconazol + terbinafina que mostró sinergia frente al 84% de los aislamientos de Fusarium. Otras combinaciones sinérgicas fueron: voriconazol + itraconazol (50%), voriconazol + fluconazol (50%), voriconazol + miconazol (38%), voriconazol + flucitosina (22%) y voriconazol + ketoconazol (25%). Las sinergias observadas con las combinaciones de itraconazol fueron itraconazol + terbinafina (25%), e itraconazol + flucitosina (9,37%). Los antagonismos observados fueron voriconazol + fluconazol (3%) e itraconazol + flucitosina (12,5%). Conclusiones: La sinergia observada con voriconazol + terbinafina fue extraordinaria. Para dilucidar mejor la utilidad potencial de los hallazgos del presente estudio, han de realizarse nuevos estudios tanto in vivo como in vitro (AU)

Background. Infections caused by Fusarium are difficult to treat because these fungi show in vitro and in vivo resistance to practically all the antifungal agents available, which explains the high mortality rates. An attempt to overcome fungal resistance is the combination of antifungal agents, especially those with different mechanisms of action. Aims. Evaluate the in vitro interactions of combinations of voriconazole or itraconazole with other antifungal agents against 32 isolates of Fusarium spp.: Fusarium chlamydosporum, Fusarium oxysporum, Fusarium proliferatum and Fusarium solani. Methods. Drug interactions were assessed by a checkerboard microdilution method that also included the determination of the MIC of each drug alone according to CLSI (Clinical and Laboratory Standards Institute) document M38-A2, 2008. Results. The best combinations were voriconazole + terbinafine which showed synergism against 84% of Fusarium strains. Other synergistic combinations were voriconazole + itraconazole (50%), voriconazole + fluconazole (50%), voriconazole + miconazole (38%), voriconazole + flucytosine (22%) and voriconazole + ketoconazole (25%). The synergisms observed with itraconazole combinations were itraconazole + terbinafine (25%) and itraconazole + flucytosine (9.37%). The antagonisms observed were: voriconazole + fluconazole (3%) and itraconazole + flucytosine (12.5%). Conclusions. The synergism showed by voriconazole + terbinafine was remarkable. To better elucidate the potential usefulness of our findings, new in vivo and in vitro studies deserve be performed (AU)

Synergysm of voriconazole or itraconazole with other antifungal agents against species of Fusarium.

BACKGROUND: Infections caused by Fusarium are difficult to treat because these fungi show in vitro and in vivo resistance to practically all the antifungal agents available, which explains the high mortality rates. An attempt to overcome fungal resistance is the combination of antifungal agents, especially those with different mechanisms of action. AIMS: Evaluate the in vitro interactions of combinations of voriconazole or itraconazole with other antifungal agents against 32 isolates of Fusarium spp.: Fusarium chlamydosporum, Fusarium oxysporum, Fusarium proliferatum and Fusarium solani. METHODS: Drug interactions were assessed by a checkerboard microdilution method that also included the determination of the MIC of each drug alone according to CLSI (Clinical and Laboratory Standards Institute) document M38-A2, 2008. RESULTS: The best combinations were voriconazole+terbinafine which showed synergism against 84% of Fusarium strains. Other synergistic combinations were voriconazole+itraconazole (50%), voriconazole+fluconazole (50%), voriconazole+miconazole (38%), voriconazole+flucytosine (22%) and voriconazole+ketoconazole (25%). The synergisms observed with itraconazole combinations were itraconazole+terbinafine (25%) and itraconazole+flucytosine (9.37%). The antagonisms observed were: voriconazole+fluconazole (3%) and itraconazole+flucytosine (12.5%). CONCLUSIONS: The synergism showed by voriconazole+terbinafine was remarkable. To better elucidate the potential usefulness of our findings, new in vivo and in vitro studies deserve be performed.