Treatment of chlamydial pneumonia of infancy.

Infants with untreated chlamydial pneumonia shed Chlamydia trachomatis and are symptomatic for may weeks. We used sulfisoxazole, 150 mg/kg/day, or erythromycin ethyl succinate, 40 mg/kg/day, for approximately 14 days to treat 32 patients with chlamydial pneumonia of infancy, and observed them for nasopharyngeal shedding of C trachomatis and changing clinical status. All infants stopped shedding chlamydiae soon after treatment was started. After treatment, three of the 25 infants tested again became culture positive (but did not have clinical relapse). All infants improved clinically. In 24 (83%) of 29 infants, where the onset of improvement could be times, improvement began within seven days of starting treatment. Progression to complete recovery was observed in 27 of 28 infants examined between two weeks and two months of treatment completion. Neither the existence of concomitant viral infection nor the duration of illness or hospitalization before starting treatment influenced the interval between initiation of treatment and onset of clinical improvement. While these observations do not prove, they are at least compatible with the hypotheses that C trachomatis plays a central etiologic role in this illness and that termination of chlamydial infection is beneficial clinically. Pending the availibility of data from controlled studies, we believe that either of the treatment programs outlined warrant consideration in the clinical management of patients with chlamydial pneumonia of infancy.