The WHO multicenter study on Listeria monocytogenes subtyping: Random amplification of polymorphic DNA (RAPD)

As part of a WHO multicenter study on Listeria monocytogenes subtyping methods the random amplification of polymorphic DNA (RAPD)-technique was evaluated. Six participants were asked to use a standard protocol to analyse a set of 80 L. monocytogenes strains. This set contained 22 groups of epidemiologically linked isolates and 11 pairs of duplicate strains. Using three different 10-mer primers, the median reproducibility of the RAPD-results obtained by the six participants was 86.5% (range 0–100%). Failure in reproducibility was mainly due to results obtained with one particular primer. The number of epidemiological groups found to be homogeneous varied from 1–22 (median 16). However, for some groups an inhomogeneity was found by the majority of participants. The overall correlation between the results from the different participants ranged from 32 to 85%.