Co-infection or early superinfection of pneumococcal pneumonia.

Two cases of co-infection or very early superinfection of pneumococcal pneumonia with Staphylococcus aureus in one case, and Enterobacter cloacae in the other, are reported. The two patients were not fully immunocompetent, had leukopenia and a mild intravascular coagulation, and were bacteremic. Mixed infection probably accounted for the lethal outcome because initial antibiotherapy was only directed against Streptococcus pneumoniae. Accurate bacteriologic methods are required to delineate contaminating and infecting pathogens when another bacteria is found in initial bronchial samples of patients with pneumococcal pneumonia, and the antibiotherapy might be directed against the two pathogens until quantitative bacteriologic results would be available, especially in old and debilitated patients. The incidence of mixed infection in pneumococcal pneumonia seems low.