Genetic typing of human and food isolates of Listeria monocytogenes from episodes of listeriosis

Ten clinical and food Listeria monocytogenes strains isolated during the epidemiological investigations of episodes of listeriosis (one outbreak and two sporadic cases) that occurred in northern Italy during 1993–1995 have been examined by DNA macrorestriction pattern analysis obtained by PFGE and RAPD typing, in order to confirm the food vehicle of infections. The same DNA profiles within the isolates from the three episodes were obtained by both techniques. The ApaI and SmaI PFGE profiles and RAPD patterns with primer OPM-01 confirmed the close relationship between strains from two distinct episodes. However, RAPD analysis with primer UBC-127 distinguished between these L. monocytogenes isolates.