Colonization of dental plaques: a reservoir of respiratory pathogens for hospital-acquired pneumonia in institutionalized elders

Abstract

Study objectives: Poor dental hygiene has been linked to respiratory pathogen colonization in residents of long-term care facilities. We sought to investigate the association between dental plaque (DP) colonization and lower respiratory tract infection in hospitalized institutionalized elders using molecular genotyping.

Methods: We assessed the dental status of 49 critically ill residents of long-term care facilities requiring intensive care treatment. Plaque index scores and quantitative cultures of DPs were obtained on ICU admission. Protected BAL (PBAL) was performed on 14 patients who developed hospital-acquired pneumonia (HAP). Respiratory pathogens recovered from the PBAL fluid were compared genetically to those isolated from DPs by pulsed-field gel electrophoresis.

Measurements and results: Twenty-eight subjects (57%) had colonization of their DPs with aerobic pathogens. Staphylococcus aureus (45%) accounted for the majority of the isolates, followed by enteric Gram-negative bacilli (42%) and Pseudomonas aeruginosa (13%). The etiology of HAP was documented in 10 patients. Of the 13 isolates recovered from PBAL fluid, nine respiratory pathogens matched genetically those recovered from the corresponding DPs of eight patients.

Conclusions: These findings suggest that aerobic respiratory pathogens colonizing DPs may be an important reservoir for HAP in institutionalized elders. Future studies are needed to delineate whether daily oral hygiene in hospitalized elderly would reduce the risk of nosocomial pneumonia in this frail population.