Silent aspiration of oral bacteria in elderly patients

This study aimed to quantify and identify bacteria existing in intraoperative bronchial fluids (IBF), and evaluate the relationship between cough and/or swallowing reflexes (CSR) impairment and silent aspiration of oral bacteria (SAOB) in elderly patients. The bacterial amounts in IBF of patients with impaired CSR were higher than those with normal CSR. Predominant isolates from IBF with normal CSR were Streptococcus, Porphyromonas, Olsenella, Gemella and Veillonella, while those with impaired CSR were Streptococcus, Veillonella, Eikenella and Prevotella. These results indicate that IBF contains bacteria, probably derived from the oral microbiota, and suggest that SAOB occurs in elderly patients irrespective of impairment of CSR.