23 Jan 2023 • A promising approach to control Staphylococcus aureus bacterial colonization in people—using a probiotic instead of antibiotics—was safe and highly effective in a Phase 2 clinical trial. The new study, reported in The Lancet Microbe, found that the probiotic Bacillus subtilis markedly reduced S. aureus colonization in trial participants without harming the gut microbiota, which includes bacteria that can benefit people. The research was conducted by researchers at the National Institutes of Health led by Michael Otto, Ph.D., an NIH senior investigator at the National Institute of Allergy and Infectious Diseases (NIAID). The prevention of S. aureus infections using approaches to “decolonize” the body has gained increased attention as the spread of antibiotic resistance limits treatment options. Some decolonization strategies are controversial because they also require large amounts of antibiotics, raising concerns about damage to the microbiota and the development of antibiotic resistance. In the clinical trial, conducted in Thailand, the research team tested whether this approach works in people. They enrolled 115 healthy participants, all of whom were colonized naturally with S. aureus. A group of 55 people received B. subtilis probiotic once daily for four weeks; a control group of 60 people received a placebo. After four weeks researchers evaluated the participants’ S. aureus levels in the gut and nose. They found no changes in the control group, but in the probiotic group they observed a 96.8% S. aureus reduction in the stool and a 65.4% reduction in the nose. The researchers also found that levels of S. aureus bacteria in the gut far exceeded S. aureus in the nose, which for decades has been the focus of staph infection prevention research. This finding adds to the potential importance of S. aureus reduction in the gut. The researchers plan to continue their work by testing the probiotic in a larger and longer trial. They note that their approach probably does not work as quickly as antibiotics, but can be used for long periods because the probiotic as used in the clinical trial does not cause harm. Source: National Institute of Allergy & Infectious Diseases | Read full story