ACUTE LOWER RESPIRATORY-TRACT INFECTIONS AMONG CHILDREN LESS-THAN 5 YEARS OLD IN SANTA-FE

The etiology of acute lower respiratory tract infections (ARI) and nas opharyngeal bacterial carriage in children less than 5 years old livin g in Santa Fe city, Argentina, was studied. A total of 518 children we re included in the study: 450 suffering from ARI and 68 asymptomatic c hildren. Blood samples, pleural effusions and nasopharyngeal secretion s (NS) were obtained from children for bacterial isolations. NS was al so used for fluorescent antibody techniques, and serum samples were em ployed for detecting IgM anti Chlamydia trachomatis. A bacterial patho gen was isolated from blood in 6.2% (14/224) of the children with ARI. A total of 11 Streptococcus pneumoniae (five of them oxacillin resist ant), two Haemophilus influenzae and one Staphylococcus aureus strains were isolated. The most frequently detected pathogen in the ARI group was respiratory syncytial virus (RSV). It was found in 23.3% (105/450 ) of the children with ARI. Among children with risk of Chlamydia trac homatis infection, 24% presented high titters of specific IgM antibodi es. Main bacteria carried in NS in the ARI group were H.influenzae (31 .6%2 and S.pneumoniae (23.4%) while viridans streptococci (26.5%), H.i nfluenzae (23.5%) and Moraxella catarrhalis (22.1%) were more frequent ly isolated from controls. The most common pneumococcal types were 14 and 7 and the main type of H.influenzae was b biotype I. During the pe riod of this study, the susceptibility of the pneumococcal isolates to oxacillin decreased from 60% to 50,8%, and the H.influenzae susceptib ility to ampicillin fell from 92.3% to 79%. All the H.influenzae type b isolations were susceptible to ampicillin.