qPCR-based detection of <i>Streptococcus pneumoniae</i> versus isolation of live pneumococci from trans-nasal (n = 270), trans-oral (n = 270) and saliva (n = 270) samples analysed in the study.

<p>Figure depicts results of qPCR-based detection of <i>S</i>. <i>pneumoniae-</i>specific genes <i>lytA</i> and <i>piaA</i> and results of live <i>Streptococcus pneumoniae</i> isolation from culture-enriched trans-nasal samples (A), culture-enriched trans-oral samples (B) and culture-enriched saliva samples (C) from 135 elderly. Each symbol (dot or cross) represents an individual sample. Position of the symbol corresponds to C_<i>T</i> values for <i>lytA</i>- and <i>piaA</i>-specific signals as marked on corresponding axes. Red dots represent samples from which live pneumococci were isolated by conventional culture at primary diagnostic step or from re-culture of samples qPCR-positive for <i>S</i>. <i>pneumoniae</i>. Open dots represent samples classified with qPCR as positive yet culture-negative for <i>S</i>. <i>pneumoniae</i>. Crosses represent samples classified as negative for <i>S</i>. <i>pneumoniae</i> in the study. Dotted lines mark the threshold of sample positivity based on presence of signals for both <i>lytA</i> and <i>piaA</i> C_<i>T</i> <40 and the continuous lines represent total number of 45 cycles in each qPCR reaction. Number depicts number of samples identified as positive for <i>S</i>. <i>pneumoniae</i> by culture (in red) and by molecular method (in black). Spearman’s rank correlation coefficient (rho) and the associated <i>P</i> value (p) are shown.