“…According to our experience, phage typing as a phenotypic method and DNA macrorestriction patterns analysis (PFGE) as a genomic method appeared to be the most suitable and the most discriminative methods during this outbreak. Since 1989, various molecular typing methods have been applied to L. monocytogenes, including multilocus enzyme analysis (1,(31)(32)(33)43), ribotyping (20,21,29), DNA micro-and macrorestriction pattern analysis (4,12,30,44), and, more recently, random amplification of polymorphic DNA (RAPD) (10,25), and these methods have proved to be useful during epidemiological investigations. For coordination of the use of these new methods and better handling of the large body of results accumulated during the past 10 years, a multicenter study on L. monocytogenes typing was initiated by the World Health Organization (Food Safety Unit, Geneva, Switzerland) in order to select and standardize the most appropriate methods and to define a common nomenclature for varieties.…”