Minimum inhibitory concentration (MIC) of crude preparations of Brevibacillus laterosporus SA14 bioactive material compared to vancomycin and oxacillin, against clinical isolates of methicillin-resistant Staphylococcus aureus

Secondary metabolites, particularly bioactive compounds, from probiotic bacteria, are good candidates for replacing antibiotics to which bacteria have become resistant. In order to compare bioactive crude material from strain SA14 of Brevibacillus laterosporus with two antibiotics, the MICs of this bioactive crude and those of antibiotics vancomycin and oxacillin, against methicillin-resistant Staphylococcus aureus (MRSA), were determined. The result indicated that the MIC (3.6–19.2 μg/ml) of bioactive crude was higher than vancomycin (MIC = 1.28–2.56 μg/ml) when tested against MRSA. Interestingly, all tested strains of MRSA were susceptible to bioactive crude and were approximately 5.2-fold more potent than oxacillin (MIC > 100 μg/ml). Its activity against MRSA gives support for further evaluation, and the development of this substance for therapeutic use.