The time course of oral colonization by Respiratory pathogens related to dental hygiene service provision in long-term care residents
C.M. Steele, M.N. Yoon, R. ellen, S.M. Poutanen, J. Wimmer, T. Hebbes
Funder: Collaborative Research Program in Rehabilitation and Long-Term Care. Funding also submitted to CIHR Pilot Projects in Aging competition June 2005.

Pneumonia is known to be a major problem in long-term care. It is the leading cause of acute care hospitalization and the primary cause of death in many diseases found amongst long-term care residents. The oral health of the aged population in these facilities has been implicated as a precipitating factory for pneumonia.

The oral cavity is a reservoir for the colonization and proliferation of bacteria; some of these bacteria are known to be aspirated (inhaled into the respiratory system) and contribute to the pathogenesis of pulmonary infections such as aspiration pneumonia. Individuals who reside in long-term care facilities are reported to be at high risk for morbidities secondary to poor oral hygiene. Aggressive oral hygiene interventions have been reported to be effective in reducing both morbidities and mortality in nursing home residents. Yet, it remains unknown whether routine dental hygiene and oral care constitutes an effective method of limiting the oral presence of respiratory pathogens, and what the time course of respiratory pathogen colonization is in the oral secretions of long-term care residents, under standard oral care conditions.

The proposed research will explore these questions, by measuring the presence of respiratory pathogens in oral swabs collected from the dorsal surface of the tongue of long-term care residents across the interval between dental hygiene appointments. Answers from this research will determine the utility of bacterial analysis of oral specimens as an index both of a patient’s risk for respiratory infection and of the effectiveness of oral care interventions in limiting that risk.

The proposed study will be a longitudinal investigation of the presence and concentration of respiratory pathogens, aerobic gram-negative bacteria and Candida albicans in oral swabs collected in two Toronto-area long-term care facilities. Specifically we will explore the hypothesis that oral colonization will peak just prior to the dental hygiene appointment, will fall to its lowest point following that appointment, and will then exhibit a gradual increase with the passage of time across successive measurements. Additionally, we will analyze differences in oral colonization and recovery between two groups of participants: those who are independent versus those who are fully dependent on nursing staff for the provision of daily oral care.

If the provision of dental hygiene services is found to be associated with the predicted drop in oral colonization by these pathogenic bacteria, and if colonization then increases with the passage of time following dental hygiene appointments, this will provide proof of principle that oral hygiene interventions constitute a weapon for preventing respiratory infection. The results of this investigation will advise the design and methodology of future oral care intervention research, and will also provide important information to guide health services planning initiatives that aim to limit the incidence of aspiration pneumonia in long-term care residents.