Rapid detection of Streptococcus pneumoniae by real-time fluorescence loop-mediated isothermal amplification

Yong Xia, Xu-Guang Guo, Shan Zhou


Background and aim of study: A significant human pathogenic bacterium, Streptococcus pneumoniae was recognized as a major cause of pneumonia, and is the subject of many humoral immunity studies. Diagnosis is generally made based on clinical suspicion along with a positive culture from a sample from virtually any place in the body. But the testing time is too long. This study is to establish a rapid diagnostic method to identification of Streptococcus pneumoniae.
Methods: Our laboratory has recently developed a new platform called real-amp, which combines loopmediated isothermal amplification (LAMP) with a portable tube scanner real-time isothermal instrument for the rapid detection of Streptococcus pneumonia. Two pairs of amplification primers required for this method were derived from a conserved DNA sequence unique to the Streptococcus pneumoniae. The amplification was carried out at 63 degree Celsius using SYBR Green for 60 minutes with the tube scanner set to collect fluorescence signals. Clinical samples of Streptococcus pneumoniae and other bacteria were used to determine the sensitivity and specificity of the primers by comparing with traditional culture method.
Results: The new set of primers consistently detected in laboratory-maintained isolates of Streptococcus pneumoniae from our hospital. The new primers also proved to be more sensitive than the published species-specific primers specifically developed for the LAMP method in detecting Streptococcus pneumoniae.
Conclusions: This study demonstrates that the Streptococcus pneumoniae LAMP primers developed here have the ability to accurately detect Streptococcus pneumoniae infections by real-time fluorescence LAMP.