Detection of pneumococcal capsular antigen in saliva of children with pneumonia

Abstract

The concentration of pneumococcal capsular antigen (PCA) in saliva was examined in 44 Thai children aged between 2 months and 2 years admitted with community-acquired pneumonia and in 52 healthy controls. None of the children with pneumonia had a positive blood culture. PCA was detected by latex agglutination in the saliva of 12/44 (27%) children with pneumonia compared with 9/52 (17%) of the controls. More cases than controls had a PCA titre ≥ 10 (9/44 (20%) vs 1/52 (2%), p < 0.01). Three of the five cases with a saliva PCA titre ≥ 1000 were urine PCA antigen-positive. The salivary PCA titres were higher, but not significantly, in children with heavier pneumococcal carriage. Quantitative me..