| DOI: 10.29090/psa.2026.02.26.9302 | Pharm Sci Asia 2026; 53(2), 221-229 |
Antibacterial potential of rice-associated Acremonium sp. USSc24: Bioautography-guided fractionation and GC–MS profiling against drug-resistant Staphylococcus aureusNitipong Siriwong, Ekachai Chukeatirote*
- School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand
The rapid emergence of antibiotic-resistant Staphylococcus aureus strains poses a significant public health challenge, highlighting the need for novel antimicrobial agents. Filamentous fungi are prolific producers of bioactive secondary metabolites, yet many fungal taxa remain underexplored. In this study, ten fungal strains isolated from brown rice were cultured in Czapek–Dox broth and yeast malt broth to prepare crude extracts, which were screened for antibacterial activity against methicillin-sensitive (MSSA), methicillin-resistant (MRSA), vancomycin-intermediate (VISA), and vancomycin-resistant (VRSA) S. aureus isolates. Most extracts exhibited weak to moderate activity, whereas Acremonium sp. USSc24 displayed striking and consistent antibacterial effects, particularly in extracts produced from yeast malt broth. Disc diffusion and minimum inhibitory concentration assays confirmed broad-spectrum activity against MSSA, MRSA, and VISA strains, with no detectable inhibition of VRSA. Bioautography-guided fractionation localized antibacterial activity to a specific chromatographic fraction, and gas chromatography–mass spectrometry (GC–MS) analysis identified a chemically diverse mixture of compounds, including caryophyllene oxide, tetradecanamide, octadecenamide, and other sesquiterpenes, many of which have reported antimicrobial properties. These results suggest that the observed antibacterial activity is likely due to synergistic interactions among multiple secondary metabolites. Collectively, this study highlights Acremonium sp. USSc24 as a promising source of antibacterial compounds and provides a foundation for future isolation, structural elucidation, and in vivo evaluation of bioactive metabolites against drug-resistant S. aureus.
Keyword:
Acremonium; Antibacterial; Fungal metabolite; Rice-associated fungi
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