879. Divergent Profiles of Oral Microbiota are Associated with Risk of Healthcare-Associated Pneumonia in Humans
Session: Oral Abstract Session: Microbiome and Susceptibility to Infection
Saturday, October 22, 2011: 11:00 AM
Room: 156ABC
Background: Healthcare associated pneumonia (HCAP) is a growing public health problem.  Strategies to identify high risk patients for HCAP remain problematic, hampering effective prevention efforts. Impaired oral hygiene is a known modifiable risk factor for HCAP, but the precise alterations in oral microbiota associated with pneumonia risk are unknown. Our goal was to determine if there was an association between the oral microbial profile and subsequent development of pneumonia.

Methods: We used 16S rRNA gene pyrosequencing to compare the oral microbial profiles of healthy community dwelling adults with those at risk for HCAP (i.e., nursing home residents, and mechanically ventilated ICU patients). A total of 37 subjects were prospectively followed for 1 month for pneumonia development. 

Results: Streptococcaceae represented the dominant taxa within the oral cavity, but the average proportion differed across the three clinical settings: community dwellers (0.65), nursing home residents (0.43), and mechanically ventilated ICU patients (0.33; p=0.02 compared to community dwellers). Furthermore, ICU subjects who subsequently developed pneumonia had a significantly smaller average proportion of oral Streptococcaceae (0.07) at baseline compared to the ICU subjects who did not develop pneumonia (0.49; p=0.02). The mean weighted UniFrac distance, a measure of bacterial community composition, among ICU subjects who developed pneumonia (0.36) was significantly different than the mean weighted UniFrac distance among ICU subjects who did not develop pneumonia (0.24, p=0.005). Principal Coordinate Analysis of the weighted UniFrac distances confirmed a distinct divergence of the ICU subjects who developed pneumonia from the cluster of ICU subjects who did not develop pneumonia.

Conclusion: Oral microbial profiles differ in community dwelling adults compared to those in healthcare settings at high risk for pneumonia. Mechanically ventilated ICU subjects who subsequently developed pneumonia had a distinct divergence of their oral microbial profiles compared to ICU subjects who did not develop pneumonia. Pyrosequencing of oral microbiota may identify patients at high risk of HCAP, and suggest innovative ways for targeted prevention.

Subject Category: C. Clinical studies of bacterial infections and antibacterials including sexually transmitted diseases and mycobacterial infections (surveys, epidemiology, and clinical trials)

Samit Joshi, DO, MPH, Can Bruce, Ph.D., Sukanya Narasimhan, PhD, Joseph Y. Kim, M.D., Erol Fikrig, MD and Vincent Quagliarello, MD, Internal Medicine, Yale University School of Medicine, New Haven, CT


S. Joshi, None

C. Bruce, None

S. Narasimhan, None

J. Y. Kim, None

E. Fikrig, None

V. Quagliarello, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.