This study evaluated the role of periodontal pathogens in 50 hospitalized patients with hospital acquired pneumonia compared with 30 healthy controls. Specimens of oropharyngeal aspirate, dental plaque bronchoalveolar lavage and blood cultured 1 or more pathogens in around 80% of patients, predominatel Staphylococcus aureus, followed by coagulase-negative staphylococci, Streptococcus pneumoniae and Klebsiell pneumoniae. Antibiotic sensitivity patterns showed concordance of bacterial cultures from dental plaque an oropharyngeal cavity in 13 patients. C-reactive protein (CRP) levels were significantly higher in patients than ii controls and there was a significant correlation between serum and salivary CR1' levels. Dental plaque bioflln may promote oral and oronpharyngeal colonization of respiratory pathogens in hospitalized subiects.