RT Journal Article SR Electronic T1 Adjusted lytA qPCR for improved detection of Streptococcus pneumoniae in community-acquired pneumonia JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA4550 DO 10.1183/13993003.congress-2019.PA4550 VO 54 IS suppl 63 A1 Nienke Paternotte A1 Bart Kamies A1 W.G. Boersma A1 W.A. Van Der Reijden YR 2019 UL http://erj.ersjournals.com/content/54/suppl_63/PA4550.abstract AB Background: Quantitative polymerase chain reaction (qPCR) targeting autolysin gene (lytA) is used to increase detection of Streptococcus pneumoniae in community-acquired pneumonia (CAP) but gives false positive results due to genetic similarities in the lytA gene of other streptococci. Our aim was to increase specificity of the lytA qPCR.Methods: NCBI GenBankĀ® was searched for overlap between sequences of the qPCR and lytA genes of related streptococci. S. pneumoniae-specific regions of the lytA gene were selected for the new qPCR. Original and new primers and probes were tested in vitro on 43 known streptococcal strains. In vivo performance of the new qPCR was then tested on 226 oropharyngeal samples of CAP-patients.Results: The lytA gene of S. pneumoniae showed overlap with the lytA gene of S. pseudopneumoniae, S. oralis and S. mitis. Primers and probe were adjusted accordingly:The original qPCR showed false positive results for S. mitis and S. oralis strains. The new design resulted in no false positives and had a more efficient reaction.Conclusion: This new lytA qPCR design showed increased specificity for detection of S. pneumoniae in CAP.FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA4550.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).