Quantitative strain-specific detection of Lactobacillus rhamnosus GG in human faecal samples by real-time PCR
Article first published online: 7 JAN 2009
© 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 106, Issue 2, pages 506–514, February 2009
How to Cite
Ahlroos, T. and Tynkkynen, S. (2009), Quantitative strain-specific detection of Lactobacillus rhamnosus GG in human faecal samples by real-time PCR. Journal of Applied Microbiology, 106: 506–514. doi: 10.1111/j.1365-2672.2008.04018.x
- Issue published online: 19 JAN 2009
- Article first published online: 7 JAN 2009
- 2008/0115: received 21 January 2008, revised 1 July 2008 and accepted 16 July 2008
- Lactobacillus rhamnosus GG;
- quantitative PCR;
- strain-specific primers
Aims: To develop a strain-specific rapid assay for identification and quantification of Lactobacillus rhamnosus GG in human faecal samples.
Methods and Results: A unique random amplified polymorphic DNA (RAPD) band of the L. rhamnosus GG strain was isolated and sequenced. Strain-specific polymerase chain reaction (PCR) primers and probes were designed based on the sequence. Quantification was performed by the real-time PCR using a fluorescent resonance energy transfer (FRET) system. The specificity of the assay was tested with DNA isolated from a set of known strains and human faecal samples. The analytical sensitivity of the method for L. rhamnosus GG was about 10 CFU per assay, which corresponds to 105 CFU g−1 of wet faeces.
Conclusions: Quantitative real-time PCR is a suitable method for strain-specific identification of L. rhamnosus GG in human faecal samples.
Significance and Impact of the Study: Lactobacillus rhamnosus GG is one of the most studied probiotic strains in clinical trials but still lacks a DNA-based identification method. This study describes a real-time PCR method for strain-specific identification and quantification of L. rhamnosus GG in human faecal samples.