DETECTION OF ESCHERICHIA COLI USING NUCLEIC ACID SEQUENCE-BASED AMPLIFICATION AND OLIGONUCLEOTIDE PROBES FOR 16S RIBOSOMAL RNA

The use of nucleic acid sequence-based amplification (NASBA), a continuous and isothermal method of in vitro nucleic acid amplification, was investigated for the specific identification of Escherichia coli (E. coli). A set of primers was selected from a highly conserved region of the 16S rRNA sequence of E. coli sandwiching a variable sequence to perform the amplification of bacterial RNA using NASBA. A probe was identified and shown to hybridize specifically to the amplified single-stranded RNA products of all tested E. coli isolates, including enterohemorrhagic serotype O157:H7. The high sensitivity of this assay system is most likely due to the large amplification power of NASBA and the high copy number of 16S rRNA.