A placebo-controlled phase II study conducted in Thailand and published in The Lancet Microbeopens showed that a Bacillus subtilis probiotic displayed the ability to remove the majority of Staphylococcus aureus colonization without changing the gut microbiome.

Until recently, oral antibiotic therapy was the only option for treating S. aureus colonization. However, the Infectious Diseases Society of America advises against this strategy because it can promote antibiotic resistance, including methicillin-resistant S. aureus (MRSA), eradicate the beneficial bacteria in the gut, and spread other infections like Clostridioides difficile.

From January to April 2021, the researchers examined 611 adult individuals from the Songkhla region of Thailand and screened them for S. aureus infection. Pregnant and breastfeeding women, those taking probiotics, or those who had diarrhea were excluded from the study.

115 people with S. aureus infection received either a placebo (n=60) or an oral probiotic (250 mg of probiotic B. subtilis MB40; n=55) for 30 days. It was observed that the oral probiotic caused a 96.8% reduction in S. aureus in stool (P<0.0001) and a 65.4% reduction in the nose (P=0.0002). No decreases in S. aureus in the gut or nose were among those given the placebo. No severe adverse events (AEs) were observed during the study. Moderate AEs were few and statistically not different from placebo in terms of frequency.

According to a press release from the NIH, B. subtilis is a promising probiotic because it can survive transit through the stomach and because its fengycin production stops "the S. aureus sensing mechanism from functioning, ultimately eradicating the bacteria." The probiotic used selectively and significantly reduces S. aureus ability to colonize rather than "killing" it.

Experts clarified that although the probiotic is not a panacea and cannot be used to treat severe S. aureus infections, it may have clinical applications. Findings indicate a pivotal role of the intestinal S. aureus colonization site and call for a categorical rethinking of S. aureus colonization dynamics and the setup of S. aureus decolonization strategies.

(Source: https://www.medpagetoday.com/infectiousdisease/generalinfectiousdisease/102709)