LAUSR

Elevated Staphylococcus aureus and oral bacterial concentrations are known to correlate with pneumonia hospitalization in nursing home residents. However, the effects of a professional oral care intervention on these factors remain unclear. The aims of this quasi-experimental study were to compare bacterial concentrations in saliva and sputum, oral health status, distribution of Staphylococcus aureus, and pneumonia status before and after a professional oral care intervention. A purposive sample of residents from two nursing homes was divided into an intervention group that received a weekly professional oral care intervention and a control group. Oral bacterial concentration was determined by real-time polymerase chain reaction. The Staphylococcus aureus distribution was determined by bacterial culture and matrix-assisted laser desorption/ionization–time of flight mass spectrometry. After data collection, a statistical analysis was performed to evaluate the effect of the intervention. Most residents were unconscious (80%), and most had a history of pneumonia (76%). Baseline demographic data did not significantly differ between the two groups. After the intervention, the intervention group had significant improvements in plaque index (1.66 ± 0.78 vs. 0.94 ± 0.64, p <  0.01), gingival index (2.36 ± 0.76 vs. 1.65 ± 0.83, p <  0.01), tongue coating index (0.96 ± 1.10 vs. 0.16 ± 0.47, p <  0.01), distribution of Staphylococcus aureus in salivary samples (11.11 ± 14.47% vs. 1.74 ± 3.75%, p = 0.02), and salivary bacterial concentration ([4.27 ± 3.65] × 105 vs. [0.75 ± 1.20] × 105, p <  0.01). Sputum bacterial concentration did not significantly differ. The intervention group also had a significantly lower annual prevalence of pneumonia hospitalization (1.24 ± 1.51 vs. 0.48 ± 0.59, p = 0.01), especially in residents whose salivary bacterial concentration exceeded the median. However, the duration of pneumonia hospitalization did not significantly differ between the two groups. A professional oral care intervention in nursing home residents can improve oral health, reduce levels of salivary bacteria and Staphylococcus aureus, and decrease the annual prevalence of pneumonia hospitalization. Trial registration: ClinicalTrials.gov, NCT03874962. Registered 12 March 2019 - Retrospectively registered.