A study reported on October 10, 2018 in Nature suggests a protective role for the probiotic Bacillus subtilis against Staphylococcus aureus, a bacterium that can cause antibiotic-resistant infections, including methicillin-resistant Staphyllococcus aureus (MRSA) infection. Bacillus bacteria are commonly ingested along with vegetables, which allows the microorganisms to grow in the intestine.
By examining fecal samples from 200 healthy individuals residing in rural Thailand, Michael Otto of the National Institute of Allergy and Infectious Disease at the National Institutes of Health and colleagues discovered that the presence of Bacillus subtilus was associated with an absence of colonization of the nose and intestinal tract by S. aureus. The team found that a system in the body that senses S. aureus allows the bacteria to grow in the gut. All 101 Bacillus isolates obtained from fecal samples were shown to inhibit this system. It was determined that a class of lipopeptides known as fengycins in Bacillus subtilus were responsible for the inhibitory action and were effective against the strain that causes most MRSA infections in the United States. In mice whose intestinal tracts were colonized with S. aureus, the intake of B. subtilis spores every two days eliminated the harmful bacteria. "Probiotics frequently are recommended as dietary supplements to improve digestive health," stated Anthony S. Fauci, MD, who is the Director of the National Institute of Allergy and Infectious Disease. "This is one of the first studies to describe precisely how they may work to provide health benefits. The possibility that oral Bacillus might be an effective alternative to antibiotic treatment for some conditions is scientifically intriguing and definitely worthy of further exploration.""Ultimately, we hope to determine if a simple probiotic regimen can be used to reduce MRSA infection rates in hospitals," added Dr Otto.