Antibacterial Activity of a Mushroom - Stereum ostrea

Abstract

The antimicrobial activity of crude culture filtrate and methanol extract of Stereum ostrea was evaluated by disc diffusion method against two Gram-negative bacteria- Klebsiella pneumonia, Pseudomonas aeruginosa and three Gram-positive bacteria such as Bacillus subtilis, Staphylococcus aureus and Micrococcus sps. To determine the minimal inhibitory concentrations (MICs) we studied concentrations of 10-50 µl of crude and methanol extract of Stereum ostrea against selected bacteria. Crude culture filtrate was highly inhibitory when compared to methanol extract, which were evident through the increased zones of inhibition against Gram-negative and Gram-positive bacteria. Crude culture filtrate of Stereum ostrea showed highest and lowest percent of inhibition zone against Bacillus subtilis (15.9 mm) and Klebsiella pneumonia (9.1mm). These results indicate that crude culture filtrate of Stereum ostrea possesses potential broad spectrum antimicrobial activity.

Keywords: Stereum ostrea, Crude culture filtrate, Methanol extract, Antimicrobial activity, MIC