TABLE 2 |.
Number of times each target was detected in a given watershed.
| No. of Times Target Detected | Culture-Confirmed |
PCR-Screen Positived |
||||||
|---|---|---|---|---|---|---|---|---|
|
Listeriaa |
Salmonellac | |||||||
|
Listeria spp. excluding monocytogenesb |
monocytogenes | eaeA | stx | |||||
| innocua | marthii | seeligeri | welshimeri | |||||
| IN STREAMS SAMPLED TWICE (N = 8) | ||||||||
| Zero | 8 | 8 | 6 | 6 | 5 | 1 | 0 | 0 |
| Once | 0 | 0 | 1 | 2 | 3 | 1 | 0 | 4 |
| Twice | 0 | 0 | 1 | 0 | 0 | 3 | 8 | 4 |
|
IN STREAMS SAMPLED THRICE (N = 60) | ||||||||
| Zero | 49 | 55 | 43 | 47 | 44 | 13 | 0 | 3 |
| Once | 10 | 5 | 16 | 11 | 15 | 30 | 0 | 12 |
| Twice | 1 | 0 | 1 | 1 | 1 | 12 | 6 | 26 |
| Thrice | 0 | 0 | 0 | 1 | 0 | 5 | 54 | 19 |
Overall L. innocua, L. marthii, L. monocytogenes, L. seeligeri, and L. welshimeri were isolated from 6% (12/196), 3% (5/196), 10% (20/196), 11% (21/196), and 9% (18/196) of samples, respectively. One sample was positive for both L. monocytogenes and L. marthii, and one sample was positive for both L. innocua and L. seeligeri. L. innocua, L. marthii, L. monocytogenes, L. seeligeri, and L. welshimeri were isolated from 16% (11/68), 7% (5/68), 28% (19/68), 28% (19/68), and 22% (15/68) of streams, respectively.
Listeria spp. excluding monocytogenes was isolated from 28% (55/196) of samples and 71% (48/68) of streams.
Salmonella was isolated from 42% of samples (79/196) and 75% (51/68) of streams. Four samples were PCR-screen positive for Salmonella but culture-negative for Salmonella; these samples were not considered positive for Salmonella in the analyses reported here.
The eaeA and stx genes were detected in 96% (190/196) and 68% (133/196) of samples, respectively. Additionally, the eaeA and stx genes were detected in 100% (68/68) and 96% (65/68) of streams, respectively. All stx-positive samples were also eaeA-positive.