Development of one-pot single specific primer-LAMP (SSP-LAMP) for identification of Shigella genus using 16S rDNA.

Ribosomal RNA gene as a high-copy number nucleo-biomarker is extremely conserved among bacteria which limits its application to the discriminative detection approaches. We have developed a colorimetric isothermal amplification method called "single specific primer-LAMP (SSP-LAMP)" requiring only one specific primer for the amplification of the target and applied to the identification of the 16S rRNA gene in the Shigella genus. A region with high sequence homology in the genus and low homology with other bacteria was considered as the most appropriate. In that regard, a 23 bp sequence in the 16S rRNA gene of the genus was targeted based on the alignment of the gene with fifty-three closely related bacterial species, and a single specific primer along with five degenerate primers were designed. Using hydroxy-naphthol blue (HNB) as an indicator and gel electrophoresis, the proposed approach of SSP-LAMP was able to detect S. boydii, S. sonnei, S. flexneri and S. dysenteriae specifically while other species remained unidentified. The SSP-LAMP method could provide a rapid one-pot point-of-care method for molecular diagnostics of pathogens in many circumstances mainly samples with high genetic homogeneity.