Background Analysis of Community Acquired Pneumonia: Environmental Bio contamination in Residential Spaces

Objective: The cause of the prevalence increase in community-acquired pneumonia is unclear. The environmental bio contamination of residential spaces was investigated. Patients and Methods: A retrospective analysis of 146 pneumonia patients admitted between January 2019 and December 2019 was performed. Age, living status, smoking status, and nursing care status were assessed. Bio contamination in residential spaces and the bactericidal effects of tobacco, incense-stick smoke and electrolyzed saline (ES) were examined using Koch’s method. Results: The patients were quite old (mean age: 80.9 ± 12.6 y.o.). Living in a private residence, where smoking tobacco, pesticide and incense-stick use might be allowed, carried a low risk of pneumonia (OR: 0.026, 95% CI: 0.003–0.190). Current smokers had a low risk of pneumonia (OR: 0.348, 95%CI: 0.143–0.844). Patients that did not require nursing care had a low risk of pneumonia (OR: 0.004, 95%CI: 0.001–0.026). Significantly more colony-forming units (CFU) were detected in communal spaces than in private spaces (5.85 ± 1.41 vs 0.30 ± 0.24 CFU/5 min). Significantly more CFU were detected in places where smoking was restricted than in spaces where smoking was allowed (5.90 ± 1.49 vs 1.24 ± 0.79 CFU/5 min). However, the examined residential spaces were generally clean. The number of CFU in vocalized droplets was very high (thousands). Both tobacco and incensestick smoke had bactericidal effects on droplet-borne bio contamination; i.e., they reduced the number of CFU by >90%, as did ES solution, which also suppressed oropharyngeal bio contamination. Conclusions: Smokeless residential environment might be responsible to the prevalence increase of communityacquired pneumonia. ES might contribute to preventing pneumonia epidemics.