Poor oral hygiene is associated with the detection of obligate anaerobes in pneumonia.

Background: Oral cavity is a reservoir of various respiratory pathogens, and poor oral hygiene is associated with an increase in anaerobic bacteria in oral cavity. In addition, it positively relates higher risk of developing pneumonia and increased pneumonia-related mortality. However, the association between poor oral hygiene and increase in obligate anaerobes in the lungs of pneumonia patients is unclear.

Methods: A total of 39 patients with pneumonia in whom bronchoscopic examination and oral hygiene evaluation were performed were prospectively enrolled. The microbiota of the bronchoalveolar lavage fluid (BALF) directly obtained from the pneumonia lesion was analysed by the clone library analysis. In addition, oral hygiene evaluations were performed using oral hygiene index (OHI), tongue coating score, oral dryness, and community periodontal index of treatment needs (CPITN). The association between the detection of oral streptococci and obligate anaerobes and oral hygiene status was evaluated.

Results: Using the clone library analysis of BALF, the phylotypes of oral streptococci and obligate anaerobes were detected in 31 (79.5%) and 26 (66.7%) patients, respectively. Increased oral dryness, OHI, and CPITN, but not the tongue coating score, significantly correlated with higher rate of detection of obligate anaerobes, although no significant associations between the detection of oral streptococci in the lungs and each oral hygiene evaluation were observed. Significantly higher number of obligate anaerobes were detected in the lungs in patients with total oral hygiene score of ≥ 5 (P = 0.008).

Conclusion: Poor oral hygiene is associated with increased obligate anaerobes in the lungs of patients with pneumonia.