Oyster mushroom (Pleurotus ostreatus) extract made antibiotic-resistant Staphylococcus aureus far more sensitive to treatment. The extract suppressed the bacteria’s uspA gene—normally activated under antibiotic stress—and doubled its vulnerability, increasing inhibition zones from 8 mm to as much as 20 mm. Rich in flavonoids, tannins, and phenols, the oyster extract directly weakened resistance pathways.