Table 4.
Detection of virulence genes at initial isolation (LAB A), LAB B and LAB C.
| O Group | #Isolates Labs A and C (LAB B) | % STEC 1 LAB A | % STEC LAB B | % STEC LAB C | %stx1 + Labs A&B | % stx1 + Labs A&C | %stx2 + Labs A&B | % stx2 + Labs A&C | H Types STEC in Labs A& C (n) |
|---|---|---|---|---|---|---|---|---|---|
| O26 | 62 (52) | 71.5 a ± 3.2 | 30.0 a ± 3.2 | 8.3 a ± 3.0 | 25.5 a ± 2.9 | 8.3 b ± 3.3 | 3.6 a ± 1.3 | 0.0 a ± 0.0 | H11 (7/9) |
| O45 | 71 (0) | 80.6 ab ± 2.8 | NE 1 | 0.0 a ± 0.0 | NE | 0.0 a ± 0.0 | NE | 0.0 a ± 0.0 | None |
| O103 | 102 (31) | 69.8 a ± 3.0 | 41.9 a + 7.5 | 2.8 a ± 1.5 | 39.5 b ± 2.3 | 2.8 a ± 1.6 | 0.0 a ± 0.0 | 0.0 a ± 0.0 | H11 (2/2), H25 (1/1) |
| O111 | 34 (15) | 100.0 c ± 0.0 | 100.0 b + 0.0 | 89.5 c ± 4.5 | 100.0 c ± 0.0 | 89.5 d ± 4.5 | 0.0 a ± 0.0 | 0.0 a ± 0.0 | H8 (21/21), NM (9/13) |
| O121 | 104 (0) | 85.2 b ± 2.7 | NE | 33.0 b ± 4.2 | NE | 15.1 b ± 3.5 | NE | 16.0 b ± 3.6 | H7 (16/54), H10 (2/3) H19 (15/20), H32 (1/1) |
| O145 | 67 (0) | 80.8 ab ± 4.5 | NE | 49.3 b + 5.3 | NE | 49.3 c ± 5.9 | NE | 2.7 a ± 1.9 | NM (32/64) |
| O157:H12/H29 | 19 (19) | 93.2 c ± 2.2 | 44.2 a ± 7.6 | 0.0 a ± 0.0 | 42.9 b ± 7.7 | 0.0 a ± 0.0 | 21.4 b ± 5.9 | 0.0 a ± 0.0 | None |
| O157:H7/NM | 66 (54) | 98.7 c ± 1.4 | 98.8 b ± 1.2 | 91.4 c + 3.0 | 81.6 c ± 3.0 | 80.0 d ± 4.8 | 84.3 c ± 2.7 | 90.7 c ± 4.2 | H7 (54/55), NM (7/11) |
a,b,c,d Means in a column with different superscripts, differ (p < 0.01). 1 NE, not evaluated. 1 STEC, positive for stx1 and or stx2. Includes only isolates (n = 525) where O group was the same by PCR and TS, with a subset of these (n = 171) evaluated by LAB B. All LAB A isolates were sub-cultured and transported on slants to LAB C.