Antibacterial activity of Ganoderma sp. (Ganodermataceae) extracts against fish strains isolated

Viviane de Oliveira Garcia1, Lenise de Lima Silva2, Bibiana Petri da Silveira3, Agueda Palmira Castagna de Vargas4, Bernardo Baldisserotto5, Rafael Gomes Von Borowski6, Simone Cristina Baggio Gnoatto6, Rosa Mara Borges da Silveira1
1 Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, RS; 2 Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Av. Roraima, 1000, 97105-900, Santa Maria, RS; 3 Programa de Pós-Graduação em Medicina Veterinária, UFSM; 4 Departamento de Medicina Veterinária Preventiva, UFSM; 5 Departamento de Fisiologia e Farmacologia, UFSM; 6 Programa de Pós-Graduação em Ciências Farmacêuticas, UFRGS.
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Bacterial disease in fish promotes high mortality rates and increase in the susceptibility to other diseases, causing a considerable economic loss in the aquaculture. This study aimed to determine the antibacterial activity in vitro of Ganoderma P. Karst (Ganodermataceae) against fish strains isolated as an alternative therapeutic treatment to fish pathologies. Samples of four wild specimens of Ganoderma were collected in Rio Grande do Sul State, Brazil (2016). The specimens were analyzed morphologically macro and microscopically and, according to Torres-Torres (2012), they correspond to the G. applanatum-complex and G. multiplicatum (Mont.) Pat. Each sample was ground with a knife mil and submitted to extraction with ethanol in the proportion 1:10 (fungus/solvent) and concentrated. Antimicrobial effects of the extracts (6400-3.125 μg mL-1) were evaluated through the microdilution test (document VET01-A4, CLSI 2013) against two strains of Aeromonas hydrophila and one of Citrobacter freundii and Raoltella ornithinolytica previously collected from kidney and skin lesions of silver catfish (Rhamdia quelen). Bactericidal activity was verified against A. hydrophila strains. Samples of G. multiplicatum and G. applanatum sp2 showed minimal bactericidal concentration (MBC) of 6400μg mL-1against both A. hydrophila strains, while G. applanatum sp1 need concentrations of 3200 μg mL-1to produce the same effect. On the other hand, G. applanatum sp3 was bactericidal at 3200 and 6400μg mL-1 against A.hydrophila resistant and susceptible to rifampicin, respectively. Citrobacter freundii and Raoltella ornithinolytica were resistant to all samples tested. In conclusion, the Ganoderma sp. extracts can be a natural alternative to threat fish bacterial diseases.

References:

Clinical Laboratory Standards Institute (CLSI) (2013). Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated from Animals. Approved Standard, 4rd edn. CLSI document VET01-04. Wayne, PA: CLSI.

RYVARDEN, L. Neotropical Polypores: Introduction, Ganodermataceae, & Hymenochaetaceae. Part 1. Oslo:Synopsis Fungorum, 2004. p. 227.

TORRES-TORRES, M. G., GUZMÁN-DÁVALOS, L., GUGLIOTTA, A. M. Ganoderma in Brazil: known species and new records. Mycotaxon, v.121, n. 1, p. 93-132, 2012.