Plasmid profiles, plasmid-borne virulence genes, and corresponding phenotypes of Czech and German SF EHEC O157:H strains

StrainSerotypeCountry of originaPlasmid size (kb)/sfpA hybridizationbPresence of plasmid-borne virulence genecPhenotype
EHEC-hlyAkatPespPetpDsfpAEHEC hemolysindSfp fimbriaee
258/98O157:HCR79/+, 86/−−/−−/−−/−−/−+/4.9+
269/98O157:HCR79/+, 86/−−/−−/−−/−−/−+/4.9+
493/89O157:HG121/++/15.0−/−−/−+/3.9; 1.9+/4.9+
3072/96O157:HG121/++/15.0−/−−/−+/3.9; 1.9+/4.9+
EDL933O157:H7USA92/−+/12.0+/9.0+/7.5+/3.9; 1.9−/−+
SakaiO157:H7J92/−+/12.0+/9.0+/7.5+/3.9; 1.9−/−+
  • a CR, Czech Republic; G, Germany; USA, United States; J, Japan.

  • b Hybridization of undigested plasmids with an sfpA probe. +, positive result; −, no signal obtained.

  • c Detection of genes was performed by PCR/Southern blot hybridization with the respective probe. +, positive result; −, no signal obtained. Plasmid DNA was digested with BamHI before hybridization with the EHEC-hlyA, espP, and etpD probes and with SmaI before hybridization with the katP and sfpA probes. Sizes of hybridizing fragments (in kilobases) are shown.

  • d Production of EHEC hemolysin was sought on enterohemolysin agar. +, hemolysis present; −, no hemolysis (SF EHEC O157:H strains usually do not produce EHEC hemolysin even though they possess the hlyCABD operon).

  • e Sfp fimbriae were detected by immunoblotting with an anti-SfpA antibody. +, signal present; −, signal absent.