Bacillus aerius inhibits Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) and other antibiotic-resistant strains of S. aureus present a significant risk due to limited treatment options available to combat potentially life-threatening infections caused by these bacteria. Since staphylococci, including MRSA strains, can populate the microbiota of individuals, we hypothesized that antagonistic bacteria would also be present among these microbes. Therefore, sample swabs were collected to identify bacteria from the human microbiota capable of killing or inhibiting the growth of MRSA. Bacillus aerius was identified to have the most pronounced anti-MRSA activity and was selected for further analysis. Cellular extracts of B. aerius alone did not inhibit the growth of MRSA so we hypothesized that a cell-to-cell interaction was responsible. Microscopy studies indicate that B. aerius impedes the growth of MRSA, potentially by inducing cytotoxicity.