Open AccessReal‐time PCR assays for the detection and quantification of Streptococcus pneumoniae
Author(s) -
Park Hee Kuk,
Lee Hee Jung,
Kim Wonyong
Publication year - 2010
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2010.02044.x
Subject(s) - streptococcus pneumoniae , streptococcus oralis , streptococcus mitis , biology , microbiology and biotechnology , streptococcus , streptococcaceae , pneumococcal infections , genotype , polymerase chain reaction , gene , bacteria , genetics , antibiotics
Streptococcus pneumoniae is the main etiologic agent of pneumonia worldwide. Because the members of the viridans group streptococci share a high degree of DNA sequence homologies, phenotypic and genotypic discriminations of S. pneumoniae from the viridans group are difficult. A quantitative real‐time PCR assay targeting the capsular polysaccharide biosynthesis gene ( cpsA ) was developed as a species‐specific detection tool for S. pneumoniae . The specificity was evaluated using genomic DNAs extracted from 135 oral cocci strains. Twenty‐seven S. pneumoniae strains tested positive, whereas 108 other strains including Streptococcus pseudopneumoniae, Streptococcus mitis , and Streptococcus oralis did not show a specific signal. The linear regression of standard curves indicated high correlations between the log numbers of S. pneumoniae cells and the C T values ( R 2 =0.99). The minimal limit of detection was 32 fg of purified genomic DNA, equivalent to 14 genomes of S. pneumoniae . This new real‐time PCR method may be very useful as a rapid and specific tool for detecting and quantifying S. pneumoniae .