Development of a multiple primer RAPD assay as a tool for phylogenetic analysis in Listeria spp. strains isolated from milkproduct associated epidemics, sporadic cases of listeriosis and dairy environments

A total of 82 Listeria strains comprising four species were examined by amp lification with a multiple primer random amplified polymorphic DNA (RAPD) a ssay. It was the objective of the study to set up a procedure suitable for analysis of the relationships among strains from milkproduct-associated epi demics, strains from sporadic cases of Listeriosis and held strains from da iry products and dairy environments. In a preliminary study, 205 primers, e ach 10 bp long, were screened for suitability as primers and 44 primers sho wing reliable and reproducible RAPD patterns at a defined reaction conditio n were selected. The 82 strains were assigned to 54 RAPD groups positioned in 13 major clusters. Strains isolated during milk product-associated epide mics were found to belong to a single cluster I. Human isolates from sporad ic cases of listeriosis predominantly were assigned to four separate cluste rs. It was found that strains of clinical origin were mainly assigned to ot her clusters than strains of non-clinical origin. (C) 1999 Elsevier Science B.V. All rights reserved.