Antimicrobial activity of endophytic fungal metabolites from breadfruit (Artocarpus altilis) leaves against multidrug-resistant Staphylococcus aureus and Klebsiella spp.

Antimicrobial resistance (AMR) has become a global concern due to the growing inability of medications to treat infections. Endophytic fungi produce secondary metabolites with antimicrobial properties, making them potential sources of new drugs. This study evaluates the antimicrobial activity of crude secondary metabolites produced by endophytic fungi isolated from the leaves of Artocarpus altilis against multidrug-resistant Klebsiella spp and Staphylococcus aureus. Fresh leaves of Artocarpus altilis (Breadfruit) were collected, authenticated, and surface sterilized for fungal isolation. Fungal isolates were purified and fermented on rice medium at 30°C for 21 days. Metabolites were extracted using ethyl acetate and tested against MDR-Klebsiella spp and MDR-Staphylococcus aureus using agar well diffusion. Phytochemical screening was also conducted. Fungal extracts showed moderate activity against MDR-Klebsiella spp, with Aa-MR exhibiting the highest effect (MIC: 37.5 mg/mL). No activity was observed against MDR-Staphylococcus aureus. Phytochemical analysis revealed alkaloids, flavonoids, saponins, tannins, terpenoids, and glycosides. These findings suggest that fungal metabolites from A. altilis may be useful in treating infections caused by gram-negative bacteria.