[Usefulness of an ELISA for the diagnosis of Streptococcus pneumoniae in patients with pneumonia].Enferm Infecc Microbiol Clin. 1996 Apr; 14(4):255-7.EI
To evaluate the etiologic role of Streptococcus pneumoniae in a series of patients with community-acquired pneumonia.
By an direct ELISA the presence of Streptococcus pneumoniae capsular polysaccharide antigen in serum and urine from 125 patients with community pneumonia was evaluated. Horseradish peroxidase-labeled polyvalent antiserum (Omniserum) was used. Working dilutions of reagents were determined by checkerboarding. Positive control antigen consisted of Pneumovax 23 and negative control consisted of serum and urine samples from healthy subjects.
Antigen detection was positive in 8 of 124 (6.45%; CI 95%: 2.80-12.30%) serum samples and in 15 of 115 (13.04%; CI 95%; 7.51-20.68%) urine samples concentrated 25-fold. Pneumococcal pneumonia was diagnosed by ELISA in 17 cases (13.60%; CI 95%: 8.15-20.95%), of which one had positive blood culture. The sensitivity of the ELISA in 24 patients with definite pneumococcal pneumonia diagnosed in this series was 70.83%.
These results suggest that the ELISA is a useful method in rapid diagnosis of Streptococcus pneumoniae in patients with pneumonia.