[Etiology of lower acute respiratory infections in hospitalized infants. 3. Investigation of Chlamydia trachomatis].

Five infants with Chlamydia trachomatis associated pneumonia are analyzed. They were diagnosed out of 80 infants admitted to the hospital with pneumonia whose etiology was studied for virus, bacteria and Chlamydia trachomatis. Serum IgM antibodies to Chlamydia tr. were measured by indirect immunofluorescence (IIF), which is considered to be specific in high titers (1 greater than or equal to 32). The five cases represented 10.4% of infants studied younger than six months. One child was born by cesarean section suggesting the possibility of other non oculogenital still undefined mechanism of transmission. Clinical symptoms and laboratory findings were characteristics of those described in Chlamydia tr. pneumonia. Chlamydia trachomatis must be considered an etiologic agent in infantile pneumonia specially in the first six months of life. The high specificity and sensitivity of the IFF makes this serologic test the best non-invasive method for diagnosis of Chlamydia tr. pneumonia currently available.