RIBOTYPING FOR USE IN STUDYING MOLECULAR EPIDEMIOLOGY OF SERRATIA-MARCESCENS - COMPARISON WITH BIOTYPING

Ribotyping carried out with a nonradioactive probe (acetylaminofluoren e ribosomal RNA kit I from Eurogentec, Seraing, Belgium) was performed for the characterization of 139 hospital strains of Serratia marcesce ns, These strains, which belonged to 11 biotypes and 1 nontypeable gro up, were isolated in seven hospitals in Belgium between 1986 and 1992. EcoRI and HindIII were used to obtain cleavage patterns. Analysis of the results produced 27 different patterns with EcoRI and 23 patterns with HindIII. Typeability reached 100%, Combination of the patterns ob tained with each enzyme produced 38 distinct ribotypes. Percent simila rity values, calculated by using the Dice coefficient and unweighted-p air group average linkage clustering, showed four main clusters and ni ne subclusters of ribopatterns at a similarity rate of approximately 8 0% or less. These groups did not coincide with those delimited by biot yping, although a rather good correlation was observed. The simultaneo us use of the two methods has potential value in epidemiological studi es.