SIMULTANEOUS DETECTION OF LISTERIA SPP AND LISTERIA-MONOCYTOGENES BY REVERSE HYBRIDIZATION WITH 16S-23S RIBOSOMAL-RNA SPACER PROBES

Enzymatic amplification results showed that Listeria species have at l east two 16S-23S rRNA spacer regions of different lengths. These space r regions of L. monocytogenes, L. ivanovii and L. seeligeri were clone d after enzymatic amplification. Sequence analysis of the inserts reve aled two spacers of 245-246 bp and 496-498 bp, respectively, of which the latter included tRNA(Ala) and tRNA(lle) genes. One Listeria spp.-s pecific probe, LIS-ICG4, was deduced from the 245-bp spacer and a L. m onocytogenes-specific probe, LMO-ICG5, was inferred from the 496-bp sp acer. The Both LIS-ICG4 and LMO-ICG5 proved to be highly specific when hybridized to a large collection of Listeria strains and strains from other relevant taxa. The LiPA test herein described for the simultane ous detection of Listeria spp. and L. monocytogenes can be expanded to detect other foodborne pathogens. (C) 1995 Academic Press Limited