Novel approaches to the identification of Streptococcus pneumoniae as the cause of community-acquired pneumonia

Current diagnostic tests lack sensitivity for the identification of the bacterial etiology of pneumonia. Attempts during the past 2 decades to improve sensitivity of detection of bacterial constituents in blood by use of antibody-antigen complexes and polymerase chain reaction have been disappointing. Recent data using pneu-mococcal conjugate vaccines as probes suggest that increased levels of both C-reactive protein and procalcitonin may be useful adjuncts to chest radiographs in the selection of patients with presumed bacterial pneumonia for inclusion in clinical trials. Among pneumococcal diagnostics currently under investigation, quantitative real-time polymerase chain reaction of respiratory secretions, as well as urinary antigen detection and pneu-mococcal surface adhesin A serological analysis for adults, are candidates for use in future clinical trials of antibiotics. Acute respiratory infections are the leading infectious cause of death globally among both infants and adults [1]. Although these deaths are, in large part, attributable to community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae [2], our ability to identify pneumococci as the specific etiological agent of pneu