TABLE 3.
Prevalence of E. coli O157:H7 and of bacteriophage infecting E. coli O157:H7 (phage) in samplesa collected from two southern Alberta feedlots
| Organism type and sample origin | No. of animals per pen | Prevalence of organism (no. of samples positiveb/no. of samples tested)
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| S1c
|
S2c
|
Total
|
||||||||
| PAT | WAT | FEC | PAT | WAT | FEC | PAT | WAT | FEC | ||
| E. coli O157:H7d | ||||||||||
| Feedlot A | ||||||||||
| Pen 1 | 152 | 0/2 | 0/2 | 9/20 | 0/2 | 0/3 | 12/20 | 0/4 | 0/5 | 21/40 |
| Pen 2 | 152 | 0/2 | 0/2 | 0/20 | 2/4 | 0/4 | 11/20 | 4/6 | 0/6 | 11/40 |
| Pen 3 | 253 | 0/2 | 2/2 | 12/20 | 1/6 | 0/6 | 14/20 | 1/8 | 2/8 | 26/40 |
| Pen 4 | 153 | 1/2 | 1/2 | 10/20 | 1/7 | 0/7 | 4/20 | 2/9 | 1/9 | 14/40 |
| Feedlot B | ||||||||||
| Pen 5 | 235 | 1/1 | 2/2 | 12/20 | 0/2 | 0/2 | 13/20 | 1/3 | 2/4 | 25/40 |
| Pen 6 | 151 | 0/2 | 2/2 | 12/20 | 2/2 | 0/2 | 12/20 | 2/4 | 2/4 | 24/40 |
| Pen 7 | 138 | 2/2 | 1/2 | 15/20 | 1/2 | 0/2 | 2/20 | 3/4 | 1/4 | 17/40 |
| Pen 8 | 149 | 0/2 | 1/2 | 15/20 | 0/2 | 0/1 | 4/20 | 0/4 | 1/3 | 19/40 |
| Phage | ||||||||||
| Feedlot A | ||||||||||
| Pen 1 | 152 | 1/2 | 1/2 | 7/20 | 5/15 | 0/3 | 0/20 | 6/17 | 1/5 | 7/40 |
| Pen 2 | 152 | 9/10 | 2/2 | 19/20 | 1/20 | 1/4 | 0/20 | 10/30 | 3/6 | 19/40 |
| Pen 3 | 253 | 2/10 | 0/2 | 3/20 | 12/30 | 0/6 | 5/20 | 14/40 | 0/8 | 8/40 |
| Pen 4 | 153 | 7/10 | 2/2 | 1/20 | 9/35 | 0/7 | 1/20 | 16/45 | 2/9 | 2/40 |
| Feedlot B | ||||||||||
| Pen 5 | 235 | 0/10 | 0/2 | 3/20 | 0/10 | 0/2 | 3/20 | 0/20 | 0/4 | 6/40 |
| Pen 6 | 151 | 4/10 | 0/2 | 6/20 | 0/10 | 1/2 | 13/20 | 4/20 | 1/4 | 19/40 |
| Pen 7 | 138 | 0/10 | 0/2 | 7/20 | 3/10 | 0/2 | 4/20 | 3/20 | 0/4 | 11/40 |
| Pen 8 | 149 | 2/10 | 2/2 | 1/20 | 1/10 | 0/2 | 3/20 | 3/20 | 3/4 | 4/40 |
PAT, pooled fecal pats; WAT, water with sediment from troughs; FEC, rectally collected fecal material. In each pen, the PAT and WAT samples were collected during the 16 days immediately preceding each of the two FEC samplings.
The presence of E. coli O157:H7 was determined by enrichment and IMS. The presence of phage was determined by initial screening and/or by enrichment followed by plaque assay.
Rectal fecal samples were collected on two occasions (in eight pens; 20 animals per pen) to evaluate E. coli O157:H7 and phage shedding by individuals. FEC samples were collected during cattle processing during implant of growth promotant (S1) and at final weigh-out prior to slaughter (S2), an interval of approximately 3 to 4 months.
Assessment for E. coli O157:H7 in PAT samples was conducted on one randomly selected PAT from the five prepared per pen.