Routine Dental Checks Reduce Pneumogenic Microbes in Oral Cavity

Objectives: Pneumonia, one of the most common infectious diseases, shows higher rates of morbidity and mortality in elderly and compromised individuals. Poor oral health has been suggested to be a significant risk factor for the disease, though little is known about acquisition of pathogens that could cause bacterial pneumonia. We investigated the prevalence of pneumogenic pathogens harbored in the oral cavity of independent elderly Japanese, and analyzed factors related to the harboring and acquisition of those microorganisms.

Methods: The study cohort consisted of 110 community-dwelling, independent Japanese elderly. Dental examinations were conducted by 5 calibrated dentists and information regarding oral health was collected by questionnaire. Twelve species of pneumogenic pathogens were detected in salivary samples and identified using a PCR method.

Results: PCR results revealed opportunistic pathogens in 67.3% of the participants, with Staphylococcus aureus, Klebsiella pneumoniae, Haemophilus influenzae, Serratia marcescens, and Candida spp. isolated from 17, 4, 38, 3 and 38 subjects, respectively. In contrast, S. pneumoniae, MRSA, P. aeruginosa, M. catarrhalis, and S. pyogenes were not detected in any. Age was significantly greater in subjects harboring H. influenzae and C. albicans. Eighty-two of the subjects received routine dental checks and showed a significantly lower rate of harboring S. aureus, while the frequency of dental checks had no relationship with the presence of S. aureus. Furthermore, subjects wearing removable denture prostheses showed a significantly higher frequency of harboring Candida spp. 

Conclusions: Several studies have suggested that oral hygienic intervention by experts reduces the number of oral microorganisms, resulting in reduction in the frequency of systemic disease. Based on our findings, we recommend that elderly individuals should receive routine dental care for oral health and prevention of mortal infectious diseases.