TABLE 1.
Frequencies of antibiotic resistance gene transfer from STEC isolates 6-20 and 7-63 to E. coli K-12 recipient strain MG1655 in storm water and bovine feces held at 28°C
| Donor strain | Selective antibiotic | Transfer frequencies at different sampling timesa
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Day 1 | Day 3 | Day 5 | Day 7 | Day 9 | Day 11 | Day 13 | Avg | ||
| Storm water | |||||||||
| 6-20 | Oxytetracycline | 8.93 × 10−7 | 1.86 × 10−6 | 7.50 × 10−7 | 1.04 × 10−6 | 8.93 × 10−7 | 9.64 × 10−7 | 1.04 × 10−6 | 1.06 × 10−6 |
| 6-20 | Tetracycline | <1 × 10−8 | <1 × 10−8 | <1 × 10−8 | 2.50 × 10−7 | <1 × 10−8 | <1 × 10−8 | <1 × 10−8 | <4.43 × 10−8 |
| Bovine feces | |||||||||
| 6-20 | Oxytetracycline | 3.75 × 10−6 | 7.65 × 10−6 | 7.10 × 10−6 | 1.26 × 10−5 | 7.25 × 10−6 | 1.12 × 10−5 | 1.71 × 10−5 | 9.52 × 10−6 |
| 6-20 | Tetracycline | 1.59 × 10−6 | 1.32 × 10−6 | 1.22 × 10−6 | 3.04 × 10−6 | 8.12 × 10−6 | 2.29 × 10−5 | 2.96 × 10−5 | 9.68 × 10−6 |
| 7-63 | Oxytetracycline | 1.01 × 10−7 | 1.01 × 10−7 | 2.90 × 10−8 | 1.45 × 10−8 | 4.35 × 10−8 | <1 × 10−8 | 1.45 × 10−8 | <4.45 × 10−8 |
| 7-63 | Tetracycline | <1 × 10−8 | <1 × 10−8 | <1 × 10−8 | <1 × 10−8 | 4.35 × 10−8 | 4.35 × 10−8 | 2.90 × 10−8 | <2.23 × 10−8 |
a
The detection limit was 1 × 10−8.