Antibiotic Susceptibility and Antimicrobial Potential of Lactic Acid Bacteria Isolated from Traditional Fermented Buffalo Milk (Dadiah) against

Lactic acid bacteria (LAB) are known as generally recognized as safe (GRAS) microorganisms and have been extensively studied for their probiotic potential. One local food product that contains LAB is dadiah, which is made by fermenting buffalo milk in bamboo tubes. This study aims to evaluate the antibiotic sensitivity and antimicrobial activity of LAB isolates from dadiah, a traditional fermented buffalo milk product from Air Dingin, West Sumatra, against Staphylococcus aureus. Five LAB isolates (YAD1-YAD5) were tested against ten antibiotics using the disk diffusion method, and their antimicrobial activity was tested using the well diffusion method. The results showed that all isolates had a high total LAB population, ranging from 57 to 164 × 109 CFU/mL, with isolate YAD2 showing the highest growth. All isolates showed resistance to kanamycin and gentamicin, but were sensitive to penicillin, ampicillin, and amoxicillin with inhibition zones >20 mm. Antibacterial activity against S. aureus ranged from 7.54 to 18.66 mm, with isolate YAD2 producing the largest inhibition zone, indicating vigorous antimicrobial activity. These findings indicate that LAB from dadiah has potential as a probiotic candidate, with the ability to inhibit S. aureus growth. Further testing for molecular characterization and assessment of resistance genes is needed to ensure safety and potential application in functional foods and probiotic-based therapies.