Detection of Streptococcus pneumoniae in Sputum Samples by Real-Time PCR

Background: Conventional laboratory culture-based methods for diagnosis of Streptococcus pneumoniae are time-consuming and yield false negative results. Molecular methods including real-time (RT)-PCR rapid methods and conventional PCR due to higher sensitivity and accuracy have replaced traditional culture assay. The aim of the current study was to evaluate lytA gene for the detection of Streptococcus pneumoniae in the cerebrospinal fluid of human patients with meningitis using real-time PCR assay. Material and Methods: In this cross-sectional study, a total of 30 clinical specimens were collected from patients in a period from September to December 2018. In order to evaluate the presence of lytA gene, conventional and real-time PCR methods were used without culture. Results: From 30 sputum samples, five (16.66%) isolates were identified as S. pneumoniae by lytA PCR and sequencing. Conclusion: In this research, an accurate and rapid real-time PCR method was used, which is based on lytA gene for diagnosis of bacteria. Based on the sequencing results, the sensitivity for the detection of lytA gene was 100% (5/5).