TABLE 3.
Characteristics of three isolates of E. coli 345-2RifC/RP1 in which phenotypic loss of antibiotic resistance was detected, as well as those of the parent strain with and without RP1
| Isolate | MIC (μg/ml)a
|
blaTEM-2
|
tetA
|
aphA
|
|||||
|---|---|---|---|---|---|---|---|---|---|
| AMP | TET | KAN | PCRb | RT-PCRc | PCRb | RT-PCRc | PCRb | RT-PCRc | |
| P1 | 4 | 1.5 | >256 | + | − | − | − | − | − |
| P2 | 3 | 2 | 2 | + | − | + | − | + | − |
| P3 | 4 | 3 | 2 | + | − | + | − | + | − |
| 345-2 RifC/RP1 | >256 | >256 | 64 | + | +++ | + | +++ | + | +++ |
| 345-2RifC | 1 | 2 | 4 | − | − | − | − | − | − |
a
AMP, ampicillin; TET, tetracycline; KAN, kanamycin.
b
+, gene could be amplified by PCR and had wild-type sequence; −, gene could not be amplified by PCR.
c
Strength of RT-PCR signal (arbitrary units): −, no signal; +, weak signal; ++, intermediate signal; +++, strong signal.