TABLE 5.
Determination of the MICs and survival rates
| Type of compound | Compounds | MIC,a,b survival ratec for: |
||
|---|---|---|---|---|
| Wild type | ΔliaF mutant | ΔliaIH mutant | ||
| Cell wall antibiotics | Bacitracin | 300 | 300 | 300 |
| Cefotaxime | 0.1, 100 | 0.1, 100 | 0.05, 10−2 | |
| Cephalexin | 0.25, 100 | 0.25, 102 | 0.125, 101 | |
| Daptomycin | 1.25, 100 | 1.25, 100 | 0.6, 10−1 to 10−2 | |
| Enduracidin | 25, 100 | 12.5, 100 | 12.5, 10−3 | |
| Nisin | 10 | 2.5 | 10 | |
| Fosfomycin | 100, 100 | 200, 100 | 50, 10−3 | |
| Vancomycin | 0.5 | 0.5 | 0.5 | |
| Oxidative stress reagents | Cumene hydroperoxide | 0.006, 100 | 0.006, 100 | 0.006, 10−2 |
| Hydrogen peroxide | 1.5 | 0.5 | 1.0 | |
| Menadione | 5, 100 | 1.25, 100 | 2.5, 10−1 | |
| Plumbagin | 5, 100 | 2.5, 100 | 1.25, 10−1 | |
| Sodium selenite | 500, 100 | 500, 100 | 125, 10−2 | |
| t-Butyl hydroperoxide | 1, 100 | 1, 100 | 0.5, 10−1 | |
| Others | Cetylpyridinium chloride | 0.5 | 0.5 | 0.5 |
| Domiphen bromide | 0.125 | 0.03 | 0.125 | |
| Phenylarsine oxide | 0.1 | 0.1 | 0.05 | |
MICs are in μg/ml with the exception of cumene hydroperoxide (%), t-butylhydroperoxide (mM) and hydrogen peroxide (%).
Values indicating explicit sensitivity or resistance of the ΔliaF and ΔliaIH mutant strains versus that of the wild-type are highlighted in bold.
Survival rates were determined by serial dilution spot tests on Mueller-Hinton agar plates at the following “critical” compound concentrations: fosfomycin, 250 μg ml−1; cefotaxime, 0.1 μg ml−1; enduracidin, 0.01 μg ml−1; daptomycin, 0.15 μg ml−1; cephalexin, 0.2 μg ml−1; plumbagin, 2.5 μg ml−1; menadione, 1.25 μg ml−1; t-butyl hydroperoxide, 0.3 mM; cumene hydroperoxide, 0.003%; sodium selenite, 125 μg ml−1. All values are given relative to the result for the wild type as a reference, which was therefore set to 100. See Fig. S3 in the supplemental material for the original data and experimental details.