Antibacterial Activity of The Fungal Metabolite Trichoderma longibrachiatum against Multidrug-Resistant Klebsiella pneumoniae and Methicillin-Resistant Staphylococcus aureus

Abstract

Extracts from sponge-associated fungus Trichoderma longibrachiatum have been studied and contain antibacterial compounds which can inhibit several pathogenic multidrug-resistant organisms. This study aims to determine the active fraction of the extract which is antibacterial against the gram-negative Multi Drug-Resistant Klebsiella. pneumoniae pathogen and gram-positive Methicillin-Resistant Staphylococcus aureus. In this study, the fungus was cultivated using solid media of malt extract agar (MEA) for 6-9 days (24 hours dark, static, pH 5.6, 60 ‰ salinity, and 27 °C). The mycelia and media were macerated by methanol and then partitioned using ethyl acetate. Active fraction tracing was carried out using the bioautography method and then isolated by the open column chromatography method. Antibacterial activity testing was done using the Broth Dilution method to determine the Minimum Inhibitory Concentration (MIC). The results of the study showed that ethyl acetate extract contained one active fraction (Rf value = 0.14), which has reactive characteristics on vanillin reagent and absorbed ultraviolet light (λ 375.5 nm absorbance peak). The active fraction was able to inhibit the growth of MDR K. pneumoniae and MRSA bacteria at the same MIC value, i.e. 256 μg mL-1. In conclusion, an active fraction of T. longibrachiatum can be developed as an antibacterial against MDR K. pneumoniae and MRSA.