A lansoprazole-like structure derived from Streptomyces metabolites: evaluation of its protective effects on hepatorenal function, antioxidant activity, and immune parameters in African catfish challenged with Staphylococcus aureus.

This study evaluated the antibacterial potential of a novel metabolite, a lansoprazole-like structure (LPZS), derived from the marine actinomycete Streptomyces huiliensis (PQ285591) against Staphylococcus aureus (MSSA). Out of 30 marine isolates from the Mediterranean Sea, S. huiliensis exhibited the most potent bioactivity. The purified metabolite, identified via NMR, TLC, HPLC, and GC-MS, demonstrated a significant minimum inhibitory concentration (MIC) of 0.5 μg/mL against S. aureus in vitro. The in vivo efficacy and safety were assessed using 120 African catfish (Clarias gariepinus) challenged with S. aureus (1.6 × 10⁶ CFU/mL). Treatment with LPZS (100 μg/mL) significantly (p < 0.05) mitigated infection-induced mortality and clinical symptoms. Furthermore, LPZS administration improved hepatorenal biomarkers, enhanced nonspecific immune responses (lysozyme and nitric oxide), and bolstered antioxidant capacity. Histopathological examination confirmed that LPZS effectively reversed tissue damage in the liver, kidney, and spleen. These findings suggest that LPZS is a safe and potent antibacterial agent, offering a promising therapeutic alternative for managing staphylococcal infections in aquaculture.