Characterization of the 16S/23S ribosomal RNA intergenic spacer regions of Listeria

Abstract

The 16S/23S ribosomal RNA (rRNA) intergenic space (IGS) regions from pathogenic and non-pathogenic species (spp.) of Listeria were characterized by the polymerase chain reaction (PCR) and DNA sequencing. DNA sequencing data for the small rRNA IGS region showed that this IGS was approximately 244 bp in length and was highly homologous (95 to 99 %) in five of the six Listeria spp examined; ie., L. monocytogenes, L. innocua, L. seeligeri, L. welshimeri, and L. ivanovii. A lower degree of homology (91 to 94 %) was detected in the large rRNA IGS region (ca. 494 bp) of these species. The DNA sequence data was used to develop two sets of oligonucleotide primers for PCR-based detection of the members of the genus Listeria. The first set of primers were Listeria genus-specific and, the second set of primers were L. monocytogenes-specific.