TABLE 2.

stx genotypes, serotypes, and Stx production by 214 STEC strainsa investigated in this study

stx genotypeNo. of isolatesSerotype (no. of isolates)Vero cell cyto- toxicity titerVTEC-RPLA titer with:
Stx1 reagentStx2 reagent
O157:H7/HO26:H11/HO103:H2/HO111:H8/HO145:HOthersRangeMedianRangeMedianRangeMedian
stx 1 b 10512125101137c16-5126416-25664<2<2
stx 1c b 120000012d32-256642-84<2<2
stx 1+stx24925121713e32-2,04825616-2566432-256128
stx 1c+stx21000001f25625688128128
stx 1+stx2c141000013g16-128488-128324-3216
stx 1+stx2+stx2c4200002h64-2561288-642432-12864
stx 1+stx2d4000004i16-1286416-322444
stx 1c+stx2d 25j0000025k16-128642-844-86
  • a All but two STEC isolates were of human origin; two strains were isolated from sheep.

  • b Both stx1 and stx1c genes were originally detected as stx1 by PCR with primer pair KS7-KS8, without restriction.

  • c O3:H2, O3:H10, O8:H (nonmotile) (three strains), O25:H (two strains), O31:H, O62:H, O84:H4, O84:H (three strains), O91:H14 (two strains), O92:H33, O112:H, O118:H (two strains), O119:H2, O128:H, O129:H, O146:H20, O152:H4, O156:H, ONT (nontypeable):H14 (two strains), ONT:H (four strains), Orough:H (five strains), Orough:HNT.

  • d O8:H19, O8:H, O74:H, O75:H33, O78:H (three strains), O112:H, O128:H, ONT:H (two strains), Orough:HNT.

  • e O4:H, O68:H4, O118:H.

  • f ONT:H.

  • g O104:H16, O113:H, O120:H.

  • h O75:H, Orough:H25.

  • i O62:H (two strains), O91:H, O128:H.

  • j Twenty-three of 25 STEC strains of the stx1c+stx2d genotype were isolated from humans; two strains (both of serotype O128:H) originated from sheep.

  • k O22:H8, O70:H, O75:H8, O75:H21, O96:H, O113:H (two strains), O128:H2 (five strains), O128:H (three strains), O128:HNT, ONT:H8 (three strains), ONT:H (two strains), Orough:H19, Orough:HNT (three strains).