TABLE 1.
Biocides utilized in this worka
| Biocide | Abbreviation | Concn (transcriptomics) | Neutralizer(s) (survival assay) | Group | Mode of action |
|---|---|---|---|---|---|
| Benzalkonium chloride | BENZ | 3.63 mg/liter | Lecithin (0.5%) and Tween 80 (1%) | Cationic agent (QAC) | Membrane damage |
| Chlorhexidine | XID | 1.48 μM | Lecithin (0.5%) and Tween 80 1%) | Cationic biguanide | Membrane damage |
| Chlorophene | PHE | 0.25 μM | Lecithin (0.5%) and Tween 80 (1%) | Halogenated phenolic | Inhibits membrane-bound proteins |
| Glutaraldehyde | GLUTA | 29 μM | Sodium bisulfite (1%) | Aldehyde | Protein denaturation and cross-linkage |
| Hydrogen peroxide | H2O2 | 272 μM | NA | Peroxygen | Oxidative |
| Ethanol | ETOH | 2.8% (vol/vol) | Dilution only | Alcohol | Membrane damage and protein denaturation |
| Isopropanol | ISOP | 2.7% (vol/vol) | Dilution only | Alcohol | Membrane damage and protein denaturation |
| Peracetic acid | PERA | 9 μM | Sodium thiosulfate (1%) and Tween 80 (1%) | Peroxygen | Oxidative |
| Povidone-iodine | POV | 12.5 μg/ml | Sodium thiosulfate (1%) | Halogen | Interacts with thiol groups on proteins |
| Sodium hypochlorite | SOD | 3.64 μM | Sodium thiosulfate (1%) | Chlorine | Oxidative |
a
The concentrations to which E. coli cells were exposed before samples were taken for transcriptomic assays are shown. The concentrations of biocides used for transcriptomics were determined to give, on average, 50% growth inhibition (according to the OD600) at 12 h compared to the growth of a control not exposed to a biocide. NA, not applicable (the assay was not performed); QAC, quaternary ammonium compound.