[Clinical analysis of patients with community-acquired pneumonia caused by a mixed infection of polymicrobial agents--including a comparative study of an infectious group with monomicrobial agents and an infectious group with unknown agents].

: We clinically analyzed 83 patients with community-acquired pneumonia caused by a mixed infection of polymicrobial agents who we have treated during the past 15 years. A comparative study among three groups; an infectious group with polymicrobial agents (83 cases), an infectious group with monomicrobial agents (335 cases), and an infectious group with unknown agents (599 cases) was performed. The results were as follows; (1) The highest percentage of patients were elderly and bedridden. (2) Striking atypical pneumonic symptoms, including dyspnea, consciousness disturbance, gastrointestinal symptoms and hypotension (shock) were present. (3) Laboratory findings of poor nutritional conditions, including decreases in serum protein, albumin, and cholineesterase, and hypoxia remarkably increased. (4) The prognosis was poor because the mortality rate (15.7%) was higher. (5) There were two polymicrobial agents for 75 patients and three agents for 8 patients. The coupling of polymicrobial agents was most frequent in five patients with Haemophilus influenzae + MSSA and five with H. influenzae + respiratory virus. These results suggest that the patients with community-acquired pneumonia caused by a mixed infection of polymicrobial agents had clinical features and causative microorganisms resembling those of elderly patients with community-acquired pneumonia. We recommended that treatment with antibiotics for them was adequate if the treatment resemble that of elderly patients.