Study finds probiotic bacillus eliminates staphylococcus bacteria

October 10, 2018, NIH/National Institute of Allergy and Infectious Diseases
Woman selling vegetable snacks in a Thai market -- a possible source of probiotic Bacillus spores. Credit: NIAID

A new study from National Institutes of Health scientists and their Thai colleagues shows that a "good" bacterium commonly found in probiotic digestive supplements helps eliminate Staphylococcus aureus, a type of bacteria that can cause serious antibiotic-resistant infections. The researchers, led by scientists at NIH's National Institute of Allergy and Infectious Diseases (NIAID), unexpectedly found that Bacillus bacteria prevented S. aureus bacteria from growing in the gut and nose of healthy individuals. Then, using a mouse study model, they identified exactly how that happens. Researchers from Mahidol University and Rajamangala University of Technology in Thailand collaborated on the project.

"Probiotics frequently are recommended as dietary supplements to improve digestive health," said NIAID Director Anthony S. Fauci, M.D. "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."

Staphylococcus infections cause tens of thousands of deaths worldwide each year. Methicillin-resistant Staphylococcus aureus, or MRSA, is familiar to many people as a cause of serious disease. Less well known is that S. aureus often can live in the nose or gut without causing any harm. However, if the skin barrier is broken, or the immune system compromised, these colonizing can cause serious infections.

One strategy to prevent Staph infections is to eliminate S. aureus colonization. However, some decolonization strategies are controversial because they require considerable amounts of topical antibiotics and have limited success, partly because they target only the nose and bacteria quickly recolonized from the gut.

The scientists recruited 200 volunteers in rural Thailand for the study. This population, they speculated, would not be as affected by food sterilization or antibiotics as people in highly developed urban areas. The scientists first analyzed fecal samples from each of the study participants for bacteria correlated with the absence of S. aureus. They found 101 samples positive for Bacillus, primarily B. subtilis—the type found mixed with other bacteria in many products. Bacillus bacteria form spores that can survive harsh environments and commonly are ingested naturally with vegetables, allowing them to temporarily grow in the intestine. The scientists then sampled the same 200 people for S. aureus in the gut (25 positive) and nose (26 positive). Strikingly, they found no S. aureus in any of the samples where Bacillus were present.

In mouse studies, the scientists discovered an S. aureus sensing system that must function for the bacteria to grow in the gut. Intriguingly, all of the more than 100 Bacillus isolates they had recovered from the human feces efficiently inhibited that system.

Using chromatography and mass spectrometry techniques, the scientists identified fengycins, a specific class of lipopeptides—molecules that are part peptide and part lipid—as the specific Bacillus substance that inhibited the S. aureus sensing system. Additional tests showed that fengycins had the same effect on several different strains of S. aureus—including high-risk USA300 MRSA which causes most community-associated MRSA infections in the United States and is an increasingly common cause of healthcare-associated MRSA infections.

To further validate their findings, the scientists colonized the gut of mice with S. aureus and fed them B. subtilis spores to mimic probiotic intake. Probiotic Bacillus given every two days eliminated S. aureus in the guts of the mice. The same test using Bacillus where fengycin production had been removed had no effect, and S. aureus grew as expected.

The NIAID and Thai scientists next plan to test whether a probiotic product that contains only B. subtilis can eliminate S. aureus in people. They plan to enroll more Thai volunteers for the project. Michael Otto, Ph.D., the NIAID lead investigator, says, "Ultimately, we hope to determine if a simple probiotic regimen can be used to reduce MRSA rates in hospitals."

Explore further: Researcher exposes MRSA risk at northeast Ohio beaches

More information: Pipat Piewngam et al, Pathogen elimination by probiotic Bacillus via signalling interference, Nature (2018). DOI: 10.1038/s41586-018-0616-y

Related Stories

Researcher exposes MRSA risk at northeast Ohio beaches

December 14, 2017
Beachgoers know there is always some risk of disease, but a recent study by a Kent State University researcher shows they may not be aware of all the dangers the beach poses.

Treatment for MRSA no longer more costly than for susceptible Staph aureus infections

May 10, 2018
A new study from the Center for Disease Dynamics, Economics & Policy (CDDEP), with collaborators from Johns Hopkins University and University of Texas Southwestern Medical Center, found that infections caused by one of the ...

Crowdsourcing friendly bacteria helps superbug cause infection

July 16, 2018
Antimicrobial resistant pathogens crowdsource friendly bacteria to survive in immune cells and cause disease, a new study by the University of Sheffield has revealed.

Researchers pioneer new eczema treatment

June 4, 2018
Eczema is the most common and stubborn skin disease in the world, but a study led by Dr. Donald Leung of the University of Colorado Anschutz Medical Campus is offering new hope for those with atopic dermatitis.

New findings detail how beneficial bacteria in the nose suppress pathogenic bacteria

August 17, 2016
Staphylococcus aureus is a common colonizer of the human body. Although, one quarter of the U.S. population live with the bacteria and never get sick, having S. aureus present in the nostrils is a risk for infections that ...

Scientists find new antibiotic right under our noses

July 27, 2016
Scientists hunting for ways to treat hard-to-beat bacterial infections have found a new antibiotic hiding right under our noses.

Recommended for you

Medical marijuana might help MS patients, but uncertainty remains

October 13, 2018
Medical products derived from marijuana might have a mild benefit in treating symptoms of multiple sclerosis, based on reports from patients.

Do not give decongestants to young children for common cold symptoms, say experts

October 11, 2018
Decongestants should not be given to children under 6—and given with caution in children under 12—as there is no evidence that they alleviate symptoms such as a blocked or runny nose, and their safety is unclear, say ...

New techniques can detect Lyme disease weeks before current tests

October 11, 2018
Researchers have developed techniques to detect Lyme disease bacteria weeks sooner than current tests, allowing patients to start treatment earlier.

Pneumonia-causing bacteria can be spread by nose picking and rubbing

October 11, 2018
Pneumonia-causing bacteria can be spread through picking and rubbing the nose, according to new research published in the European Respiratory Journal.

Plant compound found to have therapeutic effect on complications from snakebites

October 11, 2018
Rutin, a flavonoid, may complement antivenom as an effective co-treatment for envenoming from Bothrops jaraca.

Photoactive bacteria bait may help in fight against MRSA infections

October 11, 2018
Purdue University researchers are testing whether a light-active version of heme, the molecule responsible for transporting oxygen in blood circulation, may help people infected with MRSA.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.