PO-0197 Bacterial Culture Versus Pcr For Etiologic Diagnosis Of Community Acquired Pneumonia- Results From Capes (community Acquired Pneumonia Etiology Study)

Abstract

BackgroundPCR technologyholds promise to overcome the limitations of bacterial culture for confirming bacterial aetiology in childhood pneumonia. AimsTo compare the diagnostic yield using bacterial culture versus PCR in a cohort of children with community acquired pneumonia (CAP). MethodsCAPES is single-centre cohort study of 2000 consecutively enrolled children (1 month-12 years) with CAP(World Health Organisation definition). All underwent blood and nasopharyngeal aspirate (NPA) culture for bacteria. In addition, a randomly selected sub-group (10%,n = 200) underwent multiplex PCR on NPA samples to identify eight pathogenic bacteria. ResultsIn the sub-cohort of 200 children, pathogenic organisms were isolated from blood and NPA in 4(2%) and 30(15%) respectively (Figure 1). The main cohort showed similar proportions (1.7% and 14.0%) and distribution of organisms, suggesting absence of selection bias. Multiplex PCR(Figure 2) yielded traces of bacteria in 193(96.5%),with one organism detected in 44(22%), two in 76(38%), three in 53(26.5%), and four in 20(10%). Etiologic diagnosis could be confirmed by bacterial culture in4.5% cases, whereas PCR confirmed in 22%. F1"> WIDTH=200 HEIGHT=81 SRC="/small/abs_PO-0197_F001.gif" ALT="Figure 1"> View larger version (20K): F1590379F1 Abstract PO-0197 Figure 1 Bacteria detected by culture (Blood and NPA) F2"> WIDTH=200 HEIGHT=156 SRC="/small/abs_PO-0197_F002.gif" ALT="Figure 2"> View larger version (27K): F2590542F2 Abstract PO-0197 Figure 2 Bacteria detected by multiplex PCR ConclusionBacterial culture techniques appear to have limited sensitivity for etiologic diagnosis, whereas PCR has much higher sensitivity, although detection of multiple pathogenic bacteria precluded confirmation of aetiology in the majority.