Diagnosis of Streptococcus pneumoniae lower respiratory infection in hospitalized children by culture, polymerase chain reaction, serological testing, and urinary antigen detection

A prospective study of 154 consecutive high-risk hospitalized children with lower respiratory infections was conducted to determine the clinical utili ty of a pneumolysin-based polymerase chain reaction (PCR) assay compared wi th blood and pleural fluid cultures and serological and urinary antigen tes ts to determine the incidence of Streptococcus pneumoniae. Whole blood, buf fy coat, or plasma samples from 67 children (44%) tested positive by PCR. S ensitivity was 100% among 11 promptly tested culture-confirmed children and specificity was 95% among control subjects. Age, prior oral antibiotic the rapy, and pneumococcal nasopharyngeal colonization did not influence PCR re sults, whereas several surrogates of disease severity were associated with positive tests. Although serological and urinary antigen tests had comparab le sensitivity, specificity varied among infected children, and statistical agreement among all assays was limited. These findings support the use of PCR tests to evaluate the protective efficacy of pneumococcal conjugate vac cines and to identify promptly children with pretreated or nonbacteremic pn eumococcal lower respiratory infections.