Molecular and conventional typing methods for Listeria monocytogenes: The UK approach

Subtyping systems for Listeria monocytogenes have proved to be of great use in the elucidation of the epidemiology of listeriosis. Considerations for devising strategies to subtype this organism are discussed, together with the surveillance methods, work load, and resources used by the Public Health Laboratory Service in London (England). A combination of both molecular and conventional typing methods are currently in use, and these comprise the established techniques of serotyping, phage-typing, and DNA restriction- fragment length polymorphism analysis, together with the experimental procedures of resistance to arsenite and cadmium and the detection of plasmid DNA. The efficacy of this approach is assessed rising Simpson's index of diversity.