Farnesol inhibits in vitro growth of the Cryptococcus neoformans species complex with no significant changes in virulence-related exoenzymes

• Published in: Veterinary microbiology Vol. 159; no. 3-4; pp. 375 - 380
• Main Authors: Cordeiro, Rossana de Aguiar, Nogueira, George Cândido, Brilhante, Raimunda Sâmia Nogueira, Teixeira, Carlos Eduardo Cordeiro, Mourão, Charles Ielpo, Castelo-Branco, Débora de Souza Collares Maia, Paiva, Manoel de Araújo Neto, Ribeiro, Joyce Fonteles, Monteiro, André Jalles, Sidrim, José Júlio Costa, Rocha, Marcos Fábio Gadelha
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 12-10-2012; Elsevier
• Subjects: Animals; Biological and medical sciences; Candida albicans; Columbidae; Cryptococcosis - enzymology; Cryptococcosis - microbiology; Cryptococcosis - veterinary; Cryptococcus gattii - drug effects; Cryptococcus gattii - growth & development; Cryptococcus gattii - pathogenicity; Cryptococcus neoformans; Cryptococcus neoformans - drug effects; Cryptococcus neoformans - growth & development; Cryptococcus neoformans - pathogenicity; Cryptococcus neoformans species complex; Farnesol; Farnesol - pharmacology; Feces - microbiology; Fundamental and applied biological sciences. Psychology; Humans; Microbial Sensitivity Tests; Microbiology; Minimum inhibitory concentration; Miscellaneous; Mycology; Paracoccidioides brasiliensis; Peptide Hydrolases - metabolism; Phospholipases; Phospholipases - metabolism; Proteases; Virulence; Virulence Factors - metabolism; Phospholipases; Proteases; Farnesol; Cryptococcus neoformans species complex; Minimum inhibitory concentration; Yeast; Cryptococcus neoformans; Enzyme; Virulence; Esterases; Species complex; In vitro; Fungi; Peptidases; Phospholipase; Hydrolases; Fungi Imperfecti; Veterinary
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2012.04.008

Farnesol is a sesquiterpene alcohol that modulates cell-to-cell communication in Candida albicans. In recent years, several studies have shown that this molecule presents inhibitory effects against non-albicans Candida species, Paracoccidioides brasiliensis and bacteria. The present study aimed at determining the effect of farnesol on the growth of strains of the Cryptococcus neoformans species complex, through microdilution assays. In addition, the effect of farnesol on the synthesis of phospholipase and protease – important virulence-associated enzymes – by C. neoformans and Cryptococcus gattii was also investigated. A total of 36 strains were studied, out of which 20 were from veterinary sources, 8 were from human cases and 8 were from a reference collection. The minimum inhibitory concentrations (MICs) were determined in accordance with the M27-A3 protocol as described by the CLSI and farnesol was tested at a concentration range of 0.29–150μM. Phospholipase and protease activities were evaluated through growth on egg yolk agar and spectrophotometry, respectively, after pre-incubating the strains at different farnesol concentrations (MIC/4, MIC/2 and MIC). It was observed that farnesol presents an inhibitory activity against C. neoformans and C. gattii (MIC range: 0.29–75.0μM). Although farnesol did not significantly alter phospholipase activity, a tendency to decrease this activity was observed. Concerning protease, no statistically significant differences were observed when comparing the production before and after pre-incubation at different farnesol concentrations. Based on these findings, it can be concluded that farnesol has in vitro inhibitory activity against C. neoformans and C. gattii, but has little impact on the production of the analyzed virulence factors.