An RNA transcription-based amplification technique (NASBA) for the detection of viable Salmonella enterica

Possession of mRNA is indicative of cell viability. RTPCR is not appropriat e for mRNA detection as it cannot unambiguously detect mRNA in a DNA backgr ound. The alternative amplification technique, NASBA, avoids the disadvanta ges of RTPCR. We have devised a method for detection of viable Salmonella e nterica. This involves NASBA amplification of mRNA transcribed from the dna K gene. Amplification of mRNA extracted from viable and heat-killed cells f rom the same population produced consistent and highly significant (P > 0.0 1) differences between the respective signals. The signal obtained from via ble cells was completely eradicated by RNase treatment, while PCR amplifica tion of treated and untreated samples was unaffected, indicating that NASBA was unaffected by background DNA.