Twenty verocytotoxigenic Escherichia coli (VTEC) O118 strains isolated between 1996 and 1998
from human patients in Germany were analysed for their serotypes, their virulence markers
and their epidemiological relatedness. Three strains were typed as O118[ratio ]H12, these carried only
the VT2d-Ount variant gene and were not associated with diarrhoea or haemolytic uraemic
syndrome (HUS). Seventeen strains were serotyped as O118[ratio ]H16 or O118[ratio ]non-motile (NM).
These carried all the genes for VT1, eae and EHEC-haemolysin. The O118[ratio ]H16/NM strains
were from diarrhoea (13 cases) and HUS (2 cases). Sixteen of the patients were young infants
and most infections were associated with a rural environment. Evidence for zoonotic
transmission from cattle to humans was found in two cases. The epidemiological relationship
between the human and bovine O118[ratio ]H16/NM isolates was indicated by homogeneous
plasmid patterns and by very similar XbaI restriction patterns obtained by pulsed-field gel
electrophoresis. VTEC O118[ratio ]H16/NM are emerging pathogens in Germany and should be
classified as new enterohaemorrhagic E. coli (EHEC) types.