<![CDATA[Background: Skipjack tuna (Katsuwonus pelamis) bone, an abundant fishery byproduct in Indonesian waters, contains bioactive compounds such as collagen, hydroxyapatite, and antimicrobial peptides with potential antibacterial properties. Staphylococcus aureus is a leading cause of burn wound infection that is difficult to treat due to its biofilm-forming capacity, making natural antibacterial sources from fishery waste a relevant research direction. Objective: This study aimed to evaluate the in vitro antibacterial activity of skipjack tuna bone extract against S. aureus isolated from burn wound infection. Methods: Skipjack tuna bone was extracted by maceration using 70% ethanol. Antibacterial activity was tested using the disk diffusion method at extract concentrations of 20%, 40%, 60%, and 80%, with distilled water as the negative control, 70% ethanol as the solvent control, and ciprofloxacin as the positive control. Inhibition zone diameters were measured after 24 hours of incubation at 37°C. Results: Inhibition zone diameter increased with rising extract concentration, from 2.7 mm (20%) to 5.4 mm (80%). Ciprofloxacin produced a 40.1 mm inhibition zone (very strong category), ethanol produced 4.95 mm (weak category), while distilled water showed no inhibition. Based on antibacterial activity classification, extract concentrations of 20–60% were categorized as weak and 80% as moderate. Conclusion: Skipjack tuna bone extract exhibited antibacterial activity against S. aureus with a consistent increasing pattern relative to concentration, although its activity remained weak to moderate compared with ciprofloxacin. Further studies with replication and statistical analysis are needed to confirm this dose-response relationship quantitatively. ]]>
