TABLE 2.
On-farm persistence of PFGE types
| Site | PFGE type isolated at the following time (mo/yr)a:
|
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 08/99 to 11/99 | 04/00 | 05/00 | 06/00 | 07/00 | 08/00 | 09/00 | 10/00 | 11/00 | 12/00 | 01/01 | 02/01 | |
| Farm 2 | NS | NS | X39 | X39 | X39 | X39 | ||||||
| NS | NS | X44 | X44 | X44 | X44 | X44 | ||||||
| NS | NS | X45 | X45 | X45 | ||||||||
| Farm 3 | X24 | NS | X24 | X24 | X24 | − | X24 | − | − | − | − | − |
| NS | X26 | X26 | ||||||||||
| Farm 4 | X49 | NS | X46 | NS | X46 | X46 | ||||||
| X49 | NS | X49 | X49 | X49 | X49 | NS | X49 | |||||
| NS | − | X50 | X50 | NS | ||||||||
| NS | X52 | X52 | NS | |||||||||
| NS | X54 | X54 | NS | X54 | ||||||||
| Farm 5 | − | NS | X31 | X31 | − | NS | NS | NS | NS | |||
| NS | X56 | X56 | NS | NS | NS | NS | ||||||
| Farm 6 | X22 | X22 | − | − | NS | − | − | − | − | |||
| NS | X42 | X42 | ||||||||||
| Farm 8 | X8 | X8 | X8 | X8 | X8 | X8 | NS | |||||
| X25 | X25 | X25 | X25 | NS | ||||||||
| X30 | X30 | X30 | X30 | X30 | X30 | NS | ||||||
| Farm 9 | X24 | X24 | X24 | X24 | X24 | X24 | ||||||
| − | − | X26 | X26 | X26 | − | − | ||||||
| X27 | X27 | X27 | X27 | |||||||||
| Farm 10 | − | − | − | − | − | − | − | − | NS | X24 | X24 | |
| Farm 11 | NS | NS | − | NS | − | − | − | − | X8 | X8 | ||
a
−, E. coli O157 was not isolated from the premises. NS, the farm was not sampled on that occasion. An empty cell indicates that E. coli O157 isolates were obtained, but they presented PFGE types that were never found again on that farm at any sampling time.