TABLE 4.
Differential induction of mecA expression
| Strain | Genotypea | β-Galactosidase activityb with:
|
Ratio, cefoxitin/CBAPd | ||
|---|---|---|---|---|---|
| No addition | CBAP (1 μg/ml) | Cefoxitin (1 μg/ml) | |||
| GO450TF::630ΔI + pGO621C | mecR1 ΔmecI (c) | 226 ± 103 | 263 ± 76 (1)c | 2,197 ± 809 (10) | 8 |
| mecR1+mecI+ (p) | |||||
| GO450TF::630ΔI + pCH2278 | mecR1 ΔmecI (c) | 350 ± 139 | 7,812 ± 831 (22) | 17,055 ± 1,419 (49) | 2 |
| blaR1+blaI+ (p) | |||||
a
c, chromosomal; p, plasmid borne.
b
Miller units per milligram of protein per hour. Means of at least three experiments ± standard deviation.
c
Fold increase in activity as calculated by the activity in the presence of a β-lactam divided by the activity in the absence of β-lactams is shown in parentheses.
d
Fold increase in activity for cefoxitin versus CBAP induction as calculated by the activity in the presence of cefoxitin divided by the activity in the presence of CBAP.