Antimicrobial Activity of Endophytic and Rhizospheric Fungi Associated with Soft Fern (Christella sp.) and Cinderella Weed (Synedrella nodiflora) Inhabiting a Hot Spring in Los Baños, Laguna, Philippines

Background. The growing resistance of microorganisms to antimicrobial agents is a pressing public health issue. Bioprospecting efforts have mainly focused on well-known environments such as soil and animal gut in search for with antibiotic production or activity, terrestrial ecosystems endemic plants bioactive compounds. However, microbial communities thriving stressed hot springs, are potential sources metabolites that can be screened activity. There need research bioprospecting fungi antimicrobials. Objectives. study aimed test the activity endophytic rhizospheric associated soft fern (Christella spp.) Cinderella weed (Synederella nodiflora) inhabiting spring Los Banos, Laguna, Philippines. Methods. A total 23 isolated from were purified phenotypically identified. These isolates subjected agar well diffusion plug methods preliminary assays against Bacillus subtilis var. spizizenii (ATCC® 6633™), Staphylococcus  aureus 25923™), four multi-antibiotic resistant Escherichia coli (OT11, OT16, OT18, OT22), Cladosporium  cladosporioides. Based results screening, ethyl-acetate extracts selected fungal broth microdilution assay determine minimum inhibitory concentrations (MICs) antibacterial poisoned food technique percent mycelial inhibition antifungal nearest phylogenetic affiliations higher activities determined. Results. Ten seven six identified Aspergillus, Coniothyrium, Fusarium, Penicillium, Talaromyces,  Trichoderma species. Ethyl acetate UL1 (Trichoderma sp.) UL2 UR1 UR3 showed bacteria at 128-256 μg/mL concentrations. Isolates UL1, UL2, UR3, which exhibited activities, sequenced confirmed most phylogenetically related Trichoderma  virens. Eleven belonging Aspergillus spp., Coniothyrium Fusarium Penicillium Talaromyces spp. demonstrated antagonism C. isolate FCRU4 (Talaromyces sp.), where ethyl recovered testing inhibition, was islandicus. Conclusion. Endophytic asso ciated (Synedrella Philippines