Redeemed interest in discovery and characterization of naturally occurring antimicrobials arises from the fact that these compounds possess diverse biological activities useful in the development of new therapeutics. In this study, 35 fungi from extreme environments of effluent treatment plants were screened for antimicrobial activity. An isolate HKF15 produced antimicrobial compound that showed activities against pathogenic and multidrug resistant bacteria; and was identified as Fusarium sp. The active principle was separated through activity-guided HPLC fractionation of 1:1 ethyl acetate crude extract that was identified as bikaverin using HRMS and H-1 NMR. Bikaverin is known for antitumor and antifungal activity and in this study; antibacterial activity of bikaverin was assessed, emphasizing the importance of repurposing of antibiotics. (c) 2013, The Society for Biotechnology, Japan. All rights reserved.