3.3 Pneumonia characteristics
The types of pneumonia categorized were primary viral pneumonia in 39 patients (7.6% of all pneumonia cases), secondary bacterial pneumonia in 198 patients (38.7%), and a mixture of both in 230 patients (45.0%). Forty-four cases (8.6%) were judged as unclassified.
In patients with secondary bacterial pneumonia and mixture pneumonia, the microbiological etiology was determined in 156 cases (36.4%). The distribution was as indicated in Table 3. Streptococcus pneumoniae was the most common pathogen (89 cases), followed byHaemophilus influenzae (27) and Staphylococcus aureus(20); six of the 20 S. aureus strains were methicillin-resistant.