TABLE 5.
Occurrence and expression of genes for EHEC hemolysin, SLT, and alpha-hemolysin in fecal E. coli isolates from normal cattle
| No. of isolatesa | EHEC hemolysin phenotype | EHEC hemolysin A gene | SLTb | Alpha-hemolysinc |
|---|---|---|---|---|
| 20 (5) | + | + | − | − |
| 3 (3) | + | + | + | − |
| 4 (4) | − | + | − | − |
| 3 (2) | − | − | + | + |
| 137 | − | − | − | + |
| 913 | − | − | − | − |
| All isolatesd | 23 (2.1) | 27 (2.5) | 6 (0.6) | 140 (13.0) |
| All strainse | 8 | 12 | 5 | NDf |
The numbers in parentheses are the numbers of independent strains derived from different animals.
+, isolates were positive as determined by hybridization, PCR amplification, and the Vero cell assay.
+, isolates were positive as determined by hybridization and PCR amplification (most of the isolates that were positive expressed the alpha-hemolysin phenotype; the only exception was one of the isolates that belonged to the group containing 137 isolates).
Number of isolates. The numbers in parentheses are percentages.
Number of strains.
ND, not determined (isolates were not serotyped and therefore were not identified as members of strains).