Contact: Susan Lampert Smith
(608) 890-5643
ssmith5@uwhealth.org
The first-ever map of the microbiome of the human larynx shows that cigarette smoke reduces helpful bacteria and possibly sets the stage for disease.
Conversely, acid reflux seems to have no effect on the microbiome, suggesting that drugs to treat acid reflux in hopes of protecting the larynx from inflammation may be ineffective.
Researchers led by Dr. Susan Thibeault, professor of surgery-otolaryngology at the University of Wisconsin-Madison, took tissue samples from the larynxes of 97 healthy volunteers – 20 smokers and 77 non-smokers – and mapped the diversity of the microbes found on the tissues. They found that healthy non-smokers had abundant communities of bacteria from the family Comamonadaceae, which may protect against disease.
Smokers had less diverse bacterial communities, with greater abundances of Streptococcus bacteria, which are also found in vocal-fold lesions and also implicated in respiratory infections, pneumonia and ear infections.
“Less diverse microbiomes have been implicated in the disease process,” Thibeault says, noting that the imbalance in smoker’s larynxes seems to favor the Streptococcus bacteria, which are known to be involved in benign diseases of the vocal folds.
Researchers also wanted to see how acid reflux affected the microbiome of the larynx. Laryngitis, or chronic inflammation of the larynx, is thought to be caused in part by acid reflux and is often treated with proton pump inhibitors (PPIs). In 2012, people in the United States spent $9.5 billion on prescriptions for PPIs.
However, the UW researchers found that acid reflux from the stomach into the larynx or the esophagus did not seem to affect the microbiome.
“This is interesting, because if someone has reflux, you would expect the larynx to have more of the types of bacteria found in the stomach,” she says.
The study was published online in Scientific Reports, part of the Nature journal family.
The study’s lead author is graduate student Marie Jette. The work was supported by grants from the National Institutes of Health.
