Microbial agents associated with pneumonia in children from Uruguay.

The etiology of severe pneumonia, not frequently encountered in a community-based study, was determined in 204 hospitalized children less than 5 years of age. Potential pathogens were identified in 41% of episodes. Viruses were isolated or antigen was detected in 36.3% of cases; 82.4% of these cases were due to respiratory syncytial virus. Bacteria or bacterial antigens were identified in 13.2% of cases; Streptococcus pneumoniae and Haemophilus influenzae were the most frequently identified bacterial pathogens isolated from blood and/or pleural effusions. Mixed infections were identified in 4.9% of the episodes. Among the 17 patients with pleural effusion whose pleural space was drained, the etiology was suggested for 10 (58.8%). A clear-cut seasonal variation was seen, with the highest prevalence between May and October. Viral infections were more common in the first 6 months of life, although viral and bacterial infections were distributed throughout the first 5 years of life.