October 23, 2011
2 min read

Distinctive oral microbiota upped risk for hospital-acquired pneumonia

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

BOSTON — Compared with patients in the intensive care unit who did not subsequently develop pneumonia, those who did had a distinct divergence in oral microbiota. Therefore, researchers are hopeful that pyrosequencing of oral microbiota may help identify those at risk for acquiring pneumonia in the hospital setting.

Samit Joshi, DO, MD, clinical fellow at Yale University School of Medicine, and colleagues set out to determine whether an association between the oral microbial profile and subsequent development of pneumonia exists.

Saad Omer
Samit Joshi, DO, MD

"Within the past several years researchers have begun to learn how bacterial cells that live on or inside of us outnumber our own cells nine to one," Joshi said during a press conference. "These bacteria may play a role in dental caries and dental infections, but new research suggests may also play a role in the development of pneumonia."

The researchers compared oral microbial profiles of healthy adults with adults at risk for hospital-acquired pneumonia, such as those residing in nursing homes and mechanically-ventilated ICU patients. The total cohort included 37 participants that were followed for 1 month.

Overall, streptococcaceae was the most prevalent family within the oral cavity. However, the prevalence differed for healthy adults (0.65), nursing home residents (0.43) and mechanically-ventilated ICU patients (0.33; P=.02).

Compared with ICU patients who did not subsequently acquire pneumonia, those who did develop pneumonia had significantly less oral streptococcaceae at baseline (0.49 vs. 0.07; P=.02).

"Among those that did develop pneumonia, other disease-causing bacteria in the mouth increased days before the development of pneumonia," Joshi said. "This discovery has implications for how we prevent pneumonia in the future, it may lead to new and improved ways that we can prevent pneumonia by maintaining the compositions of bacteria which live inside of our mouths or by maintaining our local immune defense mechanisms." - by Jennifer Henry

For more information:

  • Joshi S. #877.Presented at: The IDSA 49th Annual Meeting; Oct. 20-23, 2011; Boston.

Disclosure: Dr. Joshi reports no relevant financial disclosures.


To me, one of the most exciting things is the idea that perhaps our microbial immunities can be markers of what our own human physiology is all about and where our health is headed. What we don't know right now is whether the two are linked causally, but regardless there is vale in understanding about these novel kinds of markers of human health and disease.

- David Relman, MD
IDSA Vice-president

Disclosure: Dr. Relman reports no relevant financial disclosures.

Twitter Follow on Twitter.