Microfloral characterization of the tongue coating and associated risk for pneumonia-related health problems in institutionalized older adults

Objectives: To characterize a comprehensive outline of the oral microflora related to pneumonia in older adults. Design: Prospective and retrospective longitudinal study. Setting: Community. Participants: Long-term hospitalized patients and people in nursing homes (343 subjects, aged ≥65). Measurements: Subjects were assessed at baseline for pneumonia-related health problems. The flora of the tongue coating was characterized according to terminal restriction fragment length polymorphism (T-RFLP) analysis. All subjects were followed prospectively for 6 months for a diagnosis of pneumonia. The number of febrile days (>37.5°C) was assessed in 299 subjects who were observed for 12 months (retrospectively for 6 months and prospectively for 6 months). The follow-up data were analyzed using multivariate regression analyses in relation to the baseline data, including T-RFLP patterns. RESUTS: T-RFLP patterns outlining the floral composition of the tongue coating were grouped into Clusters A, B, C, and D. According to Cox regression analysis, the subjects in Clusters C (hazard ratio (HR)=4.0, 95% confidence interval (CI)=1.1-15.1) and D (HR=4.9, 95% CI=1.2-21.1) were at a significantly greater risk of pneumonia than those in Cluster A, independent of other confounding factors. Logistic regression analysis adjusting for the same covariates indicated that the number of subjects with more than 9 febrile days per year was significantly lower in Cluster A than in the other clusters. Conclusion: The comprehensive microfloral profile of the tongue coating is closely related to pneumonia-related health problems in institutionalized older adults.