A posse led by Stanford microbe sleuth and microbiologist David Relman, MD, has apprehended Staphylococcus aureus, one of the most notorious sources of serious infections, lurking in formerly unsuspected nasal hideaways. The discovery may explain why attempts to expunge S. aureus from the bodies of hospitalized patients being readied for surgery often meet with less than perfect results.
About one in three of us are persistent S. aureus carriers, and another third of us are occasional carriers. This bacterial shadow, which abounds on skin (especially the groin and armpits) and is quite at home in the nose, does us no harm most of the time. But if it gets into the bloodstream or internal organs, it can cause life-threatening problems such as sepsis, pneumonia and endocarditis (infection of heart valves). That makes S. aureus not such a good thing to be coated with if you're about to have your skin punctured by a catheter or pierced by a scalpel.
This is exacerbated by the all-too-frequent presence, particularly in hospital settings, of S. aureus strains resistant to an entire family of antibiotics related to methicillin. In 2011, more than 80,000 severe methicillin-resistant S. aureus infections and more than 11,000 related deaths occurred in the U.S. alone, along with a much higher number of less-severe such infections.
In a study just published in Cell Host & Microbe, Relman - who pioneered the use of ultra-high-volume gene-sequencing techniques to sort out the thousands of species of microbes that communally inhabit our skin, orifices and innards - and his team used this method to show that mucosal sites way up high in our nose, where standard S. aureus-elimination techniques may not reach, can serve as reservoirs for S. aureus. That may, at least in part, explain why efforts to rid patients of this potentially nasty bug have so often fallen short of the mark, as I noted in my news release about the new findings:
Rigorous and somewhat tedious regimens for eliminating S. aureus residing on people’s skin or in their noses do exist, but it’s typically a matter of weeks or months before the bacteria repopulate those who are susceptible. The new study offers a possible reason why this is the case.