Further Evaluation of Multiplex PCR for Rapid Detection of Salmonella Typhi / 감염과화학요법

ABSTRACT

Typhoid fever is a class I legally designated communicable disease in Korea; and if remains as an important public health problem in many developing countries. It takes at least 3-5 days to detect and identify Salmonella Typhi (S. Typhi) by classical diagnostic method. For this reason, multiplex PCR (mPCR) was evaluated in detecting and identifying S. Typhi. In this study, forty-three bacterial strains, which consisted of 42 Salmonella enterica serovars and one Citrobacter freundii. were used to evaluate the promptness of mPCR in detecting and identifying S. Typhi. mPCR was performed with four genes which were known for representing Salmonella spp and/or S. Typhi: invA, fliC-d, viaB and prt. invA and prt gene was amplified in all strains and viaB gene was in only S. Typhi. fliC-d gene was amplified in three serovars: S. Typhi, S. Schwarzengrund and S. Livingstone. After specificity test, mPCR was modified as triplex PCR with three genes (invA, fliC-d, and viaB) and the sensitivity test was performed against S. Typhi-inoculated stool samples. mPCR was able to detect S. Typhi cell suspension of 1x105 cfu/mL. We found that modified multiplex PCR was useful to detect S. Typhi from stool samples within 24h whereas it takes 3-5days to detect by classic diagnosis method.