TABLE 1.
Results of serology and PCR assays with 54 feedlot strains
| Feedlot strain no. | Binding of MAba to bacteria passaged:
|
H7 serotype changed after passage | MAb-defined serotypec | RSS-PCR result (PCR pattern type) | Agreement between ELISA and RSS-PCR | |||
|---|---|---|---|---|---|---|---|---|
| On LB agar
|
Three times on 5% blood agarb
|
|||||||
| Anti-O157 | Anti-H7 | Anti-O157 | Anti-H7 | |||||
| 1 | No | Neg:Neg | − (B) | Yes | ||||
| 2 | No | Neg:Neg | − (C) | Yes | ||||
| 3 | ++++ | ++++ | No | O157:Neg | − (D) | Yes | ||
| 4 | No | Neg:Neg | − (E) | Yes | ||||
| 5 | ++++ | ++++ | No | Neg:H7 | − (E) | Yes | ||
| 6 | No | Neg:Neg | − (F) | Yes | ||||
| 7 | ++++ | ++++ | +++ | Yes | O157:H7 | O157:H7 | Yes | |
| 8 | ++++ | ++++ | + | Yes | O157:H7 | O157:H7 | Yes | |
| 9 | ++ | ++++ | + | ++++ | No | O157:H7 | O157:H7 | Yes |
| 10 | No | Neg:Neg | − (E) | Yes | ||||
| 11 | ++ | ++++ | No | Neg:H7 | − (E) | Yes | ||
| 12 | ++++ | ++++ | No | Neg:H7 | − (E) | Yes | ||
| 13 | No | Neg:Neg | − (G) | Yes | ||||
| 14 | + | +++ | No | Neg:H7 | − (I) | Yes | ||
| 15 | No | Neg:Neg | − (H) | Yes | ||||
| 16 | ++++ | ++++ | No | O157:Neg | − (I) | Yes | ||
| 17 | No | Neg:Neg | − (G) | Yes | ||||
| 18 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 19 | +++ | + | + | ++++ | No | O157:H7 | O157:H7 | Yes |
| 20 | ++++ | ++ | ++++ | +++ | No | O157:H7 | O157:H7 | Yes |
| 21 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 22 | ++++ | ++++ | ++ | Yes | O157:H7 | O157:H7 | Yes | |
| 23 | ++++ | ++++ | ++ | Yes | O157:H7 | O157:H7 | Yes | |
| 24 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 25 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 26 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 27 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 28 | ++ | ++ | + | ++++ | No | O157:H7 | O157:H7 | Yes |
| 29 | ++++ | ++++ | + | Yes | O157:H7 | O157:H7 | Yes | |
| 30 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 31 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 32 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 33 | ++++ | ++++ | ++ | Yes | O157:H7 | O157:H7 | Yes | |
| 34 | ++++ | +++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 35 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 36 | ++ | + | + | +++ | No | O157:H7 | O157:H7 | Yes |
| 37 | ++++ | ++++ | + | Yes | O157:H7 | O157:H7 | Yes | |
| 38 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 39 | ++++ | ++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 40 | ++++ | +++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 41 | No | Neg:Neg | − (I) | Yes | ||||
| 42 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
| 43 | No | Neg:Neg | − (I) | Yes | ||||
| 44 | No | Neg:Neg | − (I) | Yes | ||||
| 45 | No | Neg:Neg | − (I) | Yes | ||||
| 46 | No | Neg:Neg | − (I) | Yes | ||||
| 47 | No | Neg:Neg | − (J) | Yes | ||||
| 48 | ++ | No | O157:Neg | − (I) | Yes | |||
| 49 | No | Neg:Neg | − (F) | Yes | ||||
| 50 | No | Neg:Neg | − (J) | Yes | ||||
| 51 | No | Neg:Neg | − (K) | Yes | ||||
| 52 | ++++ | ++++ | No | O157:Negd | O157:H7 | No | ||
| 53 | No | Neg:Neg | − (K) | Yes | ||||
| 54 | ++++ | ++++ | ++++ | ++++ | No | O157:H7 | O157:H7 | Yes |
a
MAbs were added to wells at a 1:4,800 dilution: negative (i.e., no entry), OD405 < 0.150; +, OD405 = 0.151 to 0.400; ++, OD405 = 0.401 to 0.800; +++, OD405 = 0.801 to 1.200; ++++, OD405 > 1.200.
b
Bacteria were subcultured for 3 successive days on LB agar containing 5% sheep blood.
c
Neg, designates that the strain did not bind the anti-O157 or the anti-H7 MAb. The strains were not assayed for other O and H serotypes.
d
This strain was positive for SLTII, intimin, and flicC in a multiplex PCR (data not shown).