Clonal diversity of Shiga toxin-producing Escherichia coli O157 : H7/H- inGermany - A ten-year study

Two hundred and tell E. coli O157:H7/H- strains isolated from single cases and outbreaks of diarrhoea and haemolytic uraemic syndrome (HUS) in Germany between 1988 and 1998 were characterised by a range of molecular subtyping methods and phage typing in order to analyse their clonal nature. A high c lonal heterogeneity, together with a considerable clonal stability, has bee n identified among the bacterial isolates and no single clonal type appeare d to be geographically dominant. It is recommended to apply pulsed-field ge l electrophoresis (PFGE) together with P gene profile determination (number and genomic positions of lambdoid bacteriophages) as laboratory tools fur extended epidemiological surveillance of E. coli O157:H7/H-, whereas phage typing will remain helpful as a first line of analysis, particularly in out break situations.