TABLE 1.
Eighteen subgroups of E. coli isolates classified by genetic characterizations, susceptibility to enrofloxacin, and resistance mechanisms
| Phylogenetic type | ERIC-PCR type | Presence of virulence genes |
Presence of qnrS |
ompF expression levela |
MICENR
(μg/ml) |
No. of isolates | Representative strain no. | ||
|---|---|---|---|---|---|---|---|---|---|
| iss | traT | iroN | |||||||
| E | B | − | − | − | − | ↓ | 8 | 3 | E283 |
| B | − | − | − | − | ↓ | 16 | 7 | E50 | |
| B | − | − | + | − | ↓ | 8 | 7 | E146 | |
| B | − | − | + | − | ↓ | 16 | 4 | E119 | |
| B | − | + | + | − | ↓ | 16 | 1 | E239 | |
| C | + | + | + | + | ↓ | 128 | 1 | E241 | |
| C | + | + | + | + | ↓ | 256 | 2 | E211 | |
| B1 | A | + | + | + | − | ↓ | 32 | 5 | E10 |
| A | + | + | + | − | ↓ | 64 | 2 | E1 | |
| A | + | + | + | − | ↓ | 256 | 1 | E176 | |
| C | + | + | + | − | ↓ | 8 | 1 | E255 | |
| C | + | + | + | − | ↓ | 64 | 2 | E9 | |
| C | + | + | + | − | ↓ | 128 | 3 | E157 | |
| C | + | + | + | + | ↓ | 128 | 135 | E2 | |
| C | + | + | + | + | ↓ | 256 | 150 | E65 | |
| C | − | + | + | + | ↓ | 256 | 4 | E115 | |
| C | + | − | − | + | ↓ | 128 | 1 | E163 | |
| C | − | + | − | + | ↓ | 256 | 1 | E291 | |
a
The downward-pointing arrows mean decreased expression of ompF.