An exciting study from Tubingen in German and published in Nature has identified and isolated a new antibiotic from a commensal strain of Staphylococcus lugdunensis. Microbial warfare is clearly not new and there are many examples in the literature of bacteria competing for space and resources using toxins. However, the discovery of this new antibiotic "lugdunin" is quite rare in that the molecule is not ribosomally synthesised whereas most bacterial toxins discovered today are.
The authors of the study now claim that the human microbiome is a potentially untapped source of new antibiotics which is an exciting idea, considering that most of the antibiotics we have today come from the ground. Isolating antibiotics from the humans has the potential risk that many pathogenic strains have already been exposed to similar molecules and resistance may develop quickly. However, as the authors state in their article,
"Notably, human nasal colonization by S. lugdunensis was associated with a significantly reduced S. aureus carriage rate, suggesting that lugdunin or lugdunin-producing commensal bacteria could be valuable for preventing staphylococcal infections."
Does this mean we can treat infection using lugdunin-producing strains as probiotics? It's a complicated and possibly dangerous issue for sure, but it must be worth looking into.
The vast majority of systemic bacterial infections are caused by facultative, often antibiotic-resistant, pathogens colonizing human body surfaces. Nasal carriage of Staphylococcus aureus predisposes to invasive infection, but the mechanisms that permit or interfere with pathogen colonization are largely unknown. Whereas soil microbes are known to compete by production of antibiotics, such processes have rarely been reported for human microbiota. We show that nasal Staphylococcus lugdunensis strains produce lugdunin, a novel thiazolidine-containing cyclic peptide antibiotic that prohibits colonization by S. aureus, and a rare example of a non-ribosomally synthesized bioactive compound from human-associated bacteria. Lugdunin is bactericidal against major pathogens, effective in animal models, and not prone to causing development of resistance in S. aureus. Notably, human nasal colonization by S. lugdunensis was associated with a significantly reduced S. aureus carriage rate, suggesting that lugdunin or lugdunin-producing commensal bacteria could be valuable for preventing staphylococcal infections. Moreover, human microbiota should be considered as a source for new antibiotics.
Human commensals producing a novel antibiotic impair pathogen colonization.
Alexander Zipperer, Martin C. Konnerth, Claudia Laux, Anne Berscheid, Daniela Janek, Christopher Weidenmaier, Marc Burian, Nadine A. Schilling, Christoph Slavetinsky, Matthias Marschal, Matthias Willmann, Hubert Kalbacher, Birgit Schittek, Heike Brötz-Oesterhelt, Stephanie Grond, Andreas Peschel & Bernhard Krismer
Nature 535, 511–516 (28 July 2016) doi:10.1038/nature18634