A novel method for rapid detection of Streptococcus pneumoniae antigens in blood.

In this study, we used "RAPIRUN ® Streptococcus pneumoniae HS (otitis media/sinusitis) (RAPIRUN-HS)," a rapid S. pneumoniae antigen detection kit, to investigate methods for detecting S. pneumoniae antigens in blood of 32 bacterial pneumoniapatients. We simultaneously performed PCR to detect S. pneumoniae in blood samples. The results of these tests were compared based on pneumonia severity, determined using the Pneumonia Severity Index(PSI) score classification. Four S. pneumoniae PCR-positive patients of the six severe pneumococcal pneumoniapatients (PSI risk class IV/V) also tested positive using RAPIRUN-HS. Twenty-four mild to moderate pneumonia patients (PSI risk class IeIII) were S. pneumoniae PCR- negative; of these, 21 tested negative using RAPIRUN-HS. The pneumococcal pneumoniapatients testing positive using RAPIRUN-HS had low leukocyte counts and elevated C-reactive protein and pro- calcitonin levels, indicating that RAPIRUN-HS results were correlated with pneumonia severity. The time course evaluationsof the laboratory tests for severe pneumococcal pneumoniapatients showed that RAPIRUN-HS and S. pneumoniae PCR yielded positive results earlier than the changes in procalcitoninand IL-6. Thus, concomitant pneumococcal bacteremia was strongly suspected in patients testing positive using RAPIRUN-HS. In conclusion, RAPIRUN-HS may be useful for determining whether to admit patients into hospitals and selecting the appropriate antimicrobial agents. © 2015, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases.