Volume 9, Number 10—October 2003
Research
Cephamycin Resistance in Clinical Isolates and Laboratory-derived Strains of Escherichia coli, Nova Scotia, Canada
Brian Clarke*, Margot Hiltz*, Heather Musgrave*, and Kevin R. Forward*
Table 2
Effect of serial passage on cefoxitin gradient on promoter and attenuator regions and outer membrane protein profiles of laboratory wild type Escherichia colia,b
| Strain | MIC before serial passage (μg/mL) | MIC after serial passage (μg/mL) | Outer membrane protein profile |
|---|---|---|---|
| LD1 |
<2 |
>32 |
None |
| LD2 |
<2 |
>32 |
Omp C-, Omp F- |
| LD3 |
<2 |
16 |
Omp C-, Omp F- |
| LD4 |
<2 |
>32 |
Omp C-, Omp F- |
| LD5 |
<2 |
>32 |
Omp C-, Omp F- |
| LD6 |
<2 |
8 |
Not done |
| LD7 |
<2 |
4 |
Not done |
| LD8 |
<2 |
16 |
Omp C-, Omp F- |
| LD9 |
<2 |
>32 |
Omp C- , Omp F- |
| LD10 | <2 | >32 | Decreased production of OmpC/F |
aOnly those mutations that arose following serial passage are shown. Some parental strains had mutations initially, which were retained in the mutants.
bNo promoter/attenuator mutations affected β-lactamase production.
