Respiratory tract colonization and incidence of secondary infection during hospital treatment of community-acquired pneumonia.

In a prospective study of 245 patients with community-acquired pneumonia, the respiratory tract of 93 patients (38%) became colonized during hospitalization. Gram-negative rods and Candida spp. predominated, and in more than 75% of cases colonization occurred within 72 h after admission. Multivariate analysis showed that colonization was significantly associated with increasing age, presence of chronic disease, and with decreasing serum albumin and a respiratory rate of greater than 30/min on admission. Colonization was a negative prognostic factor, associated with a 14-fold higher mortality (10% vs. 0.7%), doubled length of hospital stay and a slower recovery. Seventeen patients developed a secondary infection. However, only two had lower respiratory tract infection, and one (0.4%) pneumonia verified by X-ray. The previously reported high risk of respiratory superinfection in this category of patient does not seem to apply today.