title: Synergistic antifungal effect of fluconazole and human polymorphonuclear leukocytes on Paracoccidioides brasiliensis: effect of interferon-gamma and granulocyte-macrophage colony-stimulating factor.
abstract: To better understand the in vivo efficacy of fluconazole (FCZ), we investigated the possible synergy of fungistatic FCZ with human polymorphonuclear leukocytes (PMN) against Paracoccidioides brasiliensis (Pb). The effect of interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in this system was also studied. For this purpose, FCZ, PMN, PMN + FCZ, PMN + IFN-gamma, PMN + IFN-gamma + FCZ, PMN + GM-CSF and PMN + GM-CSF + FCZ were co-cultured with Pb and the cfu of Pb was measured. The antifungal effect of FCZ on yeast cells of Pb was concentration-dependent. At 0.1 microg ml(-1), FCZ had no effect on the growth of Pb. At 0.2 microg ml(-1) FCZ showed a growth-inhibitory effect on three isolates of Pb in a long-term (120 h) assay, and at 0.6 microg ml(-1) or higher FCZ was fungicidal. Fungistatic concentration of FCZ (0.4 microg ml(-1)) acted synergistically with fungistatic PMN for killing isolate Bt-4 during the first 24 h of co-culture. Moreover, IFN-gamma and GM-CSF substantially enhanced the synergistic antifungal effect of PMN and FCZ. These findings provide a better understanding of why FCZ is more efficacious in in vivo models of paracoccidioidomycosis than is predicted by in vitro susceptibility tests.
authors.affiliation: Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8673, Japan. nobu@myco.pf.chiba-u.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Kurita
authors.forename: E
authors.initials: E
authors.lastname: Brummer
authors.forename: M
authors.initials: M
authors.lastname: Oarada
authors.forename: M
authors.initials: M
authors.lastname: Miyaji
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D004357:Drug Synergism; D015725:Fluconazole / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000494:pharmacology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000494:pharmacology*; D009504:Neutrophils / Q000276:immunology*; D010228:Paracoccidioides / Q000187:drug effects* / Q000276:immunology; D010229:Paracoccidioidomycosis / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D015725:Fluconazole