BACTERIAL ANTIBODY-ASSAYS IN THE DIAGNOSIS OF ACUTE LOWER RESPIRATORY-TRACT INFECTION IN CHILDREN

Bacterial antibodies were studied in acute, intermediate and convalesc ent phase sera (mean duration from first to last sample 36 days) of 12 1 children hospitalized for acute lower respiratory tract infection. A ntibody responses were observed in 45% of all cases and in 29% of the 21 children < 1 year old. A total of 15 responses to Streptococcus pne umoniae (pneumolysin), 20 to Haemophilus influenzae, 9 to Moraxella ca tarrhalis, 3 to chlamydiae and 8 to Mycoplasma pneumoniae were found, In 79 patients with 4 consecutive samples available, 52% of the 31 res ponses were measurable within 5 days from admission, Overall the respo nses were not associated with upper respiratory tract bacterial findin gs or acute otitis media. Significantly more responses were found in t he 121 children with acute lower respiratory tract infection than in h ealthy controls (P < 0.007). We conclude that bacterial antibody assay s provide a useful tool in the study of the etiology of acute lower re spiratory tract infection in young children, even if the interval betw een paired serum samples is short.