Abstract
Background:
Molluscs are invertebrate organisms known to produce secondary metabolites that help them adapt to their environment.

Aim:
This study aims to explore the potential of fungi associated with molluscs and evaluate their secondary metabolites potential antimicrobial agents against human pathogens.

Methods:
The fungi isolated from molluscs were examined both macroscopically and microscopically. Promising isolated were selected and cultured in bulk for phytochemical screening and thin-layer chromatography (TLC) analysis. Extract from these fungal tested at a concentration 1000 μg/disc. Observations recorded every 12 hours over a 36-periods. Molecular identification of the selected isolated was performed using the Quick-DNA Magbead Plus Kit (Zymo Research, D4082). Statistical analysis was used to determine the significant differences isolates and control (p <0.05).

Results:
The extract from fungal isolate G1T4 demonstrated both antibacterial and antifungal activity against all four test pathogens, as evidenced by the formation of clear inhibition zones. Extracts from isolates B3M6, B4T6, and B2L4 showed antibacterial effect against Staphylococcus aureus, Escherichia coli, and the test fungus Candida albicans, but exhibited no activity against the fungal pathogen Trichoderma harzianum. The presence of inhibition zones suggests that these extracts contain active secondary metabolites or active compounds in the associated fungus extract. The result of statistical analysis showed significant differences (p < 0.05) between isolates and controls at all observation times (12 – 72 hours) against Escherichia coli and Staphylococcus aureus, Candida albicans and Trichoderma harzianum showed GT14 are consistently higher than other isolates (p <0.05).

Conclusion:
Molecular analysis revealed that isolate G1T4 is closely related to Aspergillus subramanianii (accession number PQ325939), while isolate B3M6 is closely related to Cladosporium halotolerans (accession number PQ325940).

Key words: Human pathogens; Molluscs; Associated fungi; Secondary metabolites.