MRSA-eliminating Bacteria Found Within the Human Body

In recent years, the number of infections caused by antibiotic-resistant (AR) bacteria has greatly increased, and thus, cases of AR bacteria continue to be a public health concern.

In a recent study, researchers have discovered that there is a bacteria naturally found in the human microbiome that can be used to combat and eliminate AR bacterium, such as the potentially deadly Methicillin-Resistant Staphylococcus aureus (MRSA).

Staphylococcus aureus is a type of bacteria that resides in 30% of peoples' noses, according to the Centers for Disease Control and Prevention (CDC). In most cases, this bacterium does not cause its carrier any harm. However, a particular strain of this bacterium, MRSA, is potentially deadly since it is a multi-drug resistant organism (MDRO). According to Nature, this strain is found in two in 100 people, and kills 11,000 people in the United States, annually.

Andreas Peschel, PhD, and his colleagues at the University of Tuebingen in Germany, reported that a molecule called lugdunin, produced by the bacterium Staphylococcus lugdunensis, which is naturally found in the human nose, can be used to develop an effective antibiotic that can combat the growth of MRSA.

When asked about the implications of this discovery, Jason C. Gallagher, PharmD, FCCP, FIDSA, BCPS, president, Society of Infectious Diseases Pharmacists, told Contagion, “This study is receiving press for the fact that bacteria [that] can normally colonize the human nose produces an antibiotic that can kill Staphylococcus aureus, which includes MRSA. That in itself is not surprising, since many bacteria produce antibiotics, including many of those that we use in medicine. However, it is notable that this strain, Staphylococcus lugdunensis, is a human colonizer, and its production of this antibiotic may prevent S. aureus infections by making life miserable for it in the human nose. Since over 30% of people are colonized with S. aureus in the nose and this colonization can eventually lead to invasive infections of the skin or other body sites, it is conceivable that we could therapeutically colonize people with S. lugdunensis to prevent S. aureus infections, such as those that occur after surgery.”

In an interview with Contagion, Jeff Boyd PhD, assistant professor of Biochemistry and Microbiology, discussed how Staphylococcus aureus and MRSA infections are currently being treated.

Lugdunin and MRSA-elimination

In their article, the study authors wrote, "To investigate whether the presence of S. lugdunensis in the human nose can prevent co-colonization by S. aureus, we examined nasal swabs from 187 hospitalized patients for colonization by S. lugdunensis, S. aureus or both." Their findings revealed that patients who naturally carried S. lugdunesis within their noses were six times less likely to be S. aureus carriers than those who did not have S. lugdunesis. In a 30-day test tube trial, researchers found that S. aureus bacteria were not able to achieve resistance against lugdunin. These findings suggest that lugdunin prohibits colonization by S. aureus, and thus, can be developed into a valuable antibiotic, which can be used to prevent staphylococcal infections.

Peschel’s team’s original aim was to study S. aureus within the nose in order to better understand how the bacterium functions. After screening 90 bacteria from the nose, they found that S. lugdunensis was the only one that could eliminate MRSA, and in addition, kill other strains of S. aureus that were resistant to several antibiotics, such as glycopeptide.

In a follow-up experiment, Peschel and his team applied S. aureus to the skin of mice and found that the treatment with lugdunin strongly reduced or eliminated S. aureus on the surface of the skin and within the deeper layers of the skin. Since the nasal cavity contains the strongest risk of S. aureus, Peschel closely examined the effects of introducing S. lugdunesis into the noses of cotton rats where he found that lugdunin had reduced S. aureus colonization.

Peschel aims to develop lugdunin into an antibiotic for human use.

Kim Lewis, a microbiologist at Northeastern University in Boston, Massachusetts said in an article, “It’s the first time researchers have been able to definitively connect the production of an antibiotic in a bacterium with the suppression of a competitor in a microbiome community.”