Medicinal mushrooms with methicillin resistant <i>Staphylococcus aureus</i> (MRSA) inhibitory activity

Abstract

Although significant progress has been made in the last few decades in the field of antimicrobial chemotherapy, indiscriminate antibiotics use and the growing trend of bacterial resistance have made it necessary to search for newer antimicrobial agents. Various mushrooms have been used in the Nigerian traditional medicine to treat several infectious diseases. The aim of this work is to investigate the antimicrobial activity of five medicinal mushroom species viz. Ganoderma lucidum, Lycoperdon umbrinum, Trametes versicolor, Ganoderma applanatum and Tricholoma spp against seven clinical strains of methicillin-resistant Staphylococcus aureus (MRSA). The methanol extracts of the five mushrooms were subjected to agar diffusion and agar dilution assays to determine the antibacterial and minimum inhibitory concentration (MIC), respectively, against seven strains of MRSA. The extracts displayed varying growth inhibitory activity on the clinical strains of MRSA, with the extracts of Lycoperdon umbrinum and Trametes versicolor eliciting the highest growth inhibitory effects across the MRSA under investigation. In particular, L. umbrinum (3.125 mg/mL) had diameter of zone of inhibition (ZOI) ranging from 7 – 13 mm with MIC value as low as 1.47 mg/mL against the MRSA strains, while T. versicolor displayed ZOI between 3 mm and 12 mm. Meanwhile, the extract of the three other species displayed little antibacterial activity against the MRSA strains. The antimicrobial activity of Trametes versicolor and Lycoperdon umbrinum displayed in this study indicate they could be potential source of novel antimicrobial agents and research is needed to identify the bioactive molecules responsible for their biological activity.

Keywords: Mushroom; Methicillin-Resistant Staphylococcus aureus; Trametes versicolor; Lycoperdon umbrinum