Table 6.

Samples containing E. coli O157:H7 displaying a given REDP and phenotype from three Wisconsin dairy farmsa

FarmStrain no.No. of samplesbREDPcPhenotype
stxId stxIId Resistance toe:Carbohydrate fermf
AvrIIXbaIPen GChlortetTetSorbRha
R9207A11+++++
9221A12+++++
94421A23+++++
9572A24++++
9591A24+++++
9602NTa NTNTNT+++
9631A24++++
9641A23++++
9653A23+++++
9663A23++++
9931A24+++++
10271A23++++w+h +
103111A23++++++
10541A35+++++w++
11231A36++++
154015A47+++++
15741A48+++++
15751A47+++
X127580A59+++
13598A59++++
14875A59++++
16251A610++
16531A59++++
17071A812+++
17641A913++++
C16411A711++
  • a Isolates are from cohort animal, noncohort animal, environmental, and nonbovine animal samples from farms R and X. The positive sample from farm C was from a raccoon.

  • b Number of samples containing an O157:H7 strain with the REDP and phenotype indicated in this table.

  • c REDP were generated by using AvrII or XbaI.

  • d Presence of gene sequences of stxIor stxII.

  • e Resistance to penicillin G (PenG; 75 U/ml), chlortetracycline (Chlortet; 25 μg/ml), and tetracycline (Tet; 50 μg/ml).

  • f Fermentation of sorbitol (Sorb) and rhamnose (Rha) determined by using an API 20E test strip.

  • g NT, not typeable by CHEF-PFGE.

  • h w+, weakly positive by API 20E test strip.