Exploring the impact of oral health and vaccination on pneumonia-causing bacteria: insights from predictive modeling.

Nursing home acquired pneumonia (NHAP) is a leading cause of mortality in long-term care facilities (LTCFs), primarily resulting from the macro-aspiration of opportunistic pathogens colonizing the upper respiratory tract. While multiple bacterial species can cause NHAP, Streptococcus pneumoniae is the most common, and pneumococcal vaccination remains the primary preventative measure. Oral hygiene interventions are also increasingly explored as a complementary strategy to reduce pathogen colonization, although their reported effectiveness has been mixed, likely due to differences in how individual pathogens respond. To better understand these discrepancies, we examined whether pathogen-specific colonization patterns vary in response to oral health behaviors in elderly LTCF residents. We collected longitudinal oral and nasal colonization data for four key NHAP-associated pathogens, along with oral health survey responses, and pneumococcal vaccination status. Better oral health behaviors predicted reduced colonization with S. pneumoniae and Haemophilus influenzae, both of which were more commonly found in oral samples in this population. There was no relationship with Staphylococcus aureus and Pseudomonas aeruginosa, which were more commonly found in the nasal cavity. Our findings suggest that oral hygiene interventions will only impact NHAP risk for pathogens primarily colonizing the oral cavity, potentially explaining the mixed outcomes in prior studies.