Table 1.
Characteristics of antibiotics and biocides screened for interaction effects.
| Antibiotic | Class | Mode of action | Application | *MIC | *,#EC50 |
| Meropenem | Carbapenem; beta-lactam | Inhibition of bacterial cell wall synthesis | Broad spectrum; treatment of infections with MDR bacteria | 0.075 | 0.061 (0.004) |
| Ciprofloxacin | Fluoroquinolone | Inhibition of DNA transcription and replication | Broad spectrum | 1.5 | 0.22 (0.39) |
| Gentamicin | Aminoglycoside | Inhibition of protein synthesis | Broad spectrum; topical applications | 0.5 | 0.30 (0.07) |
| Biocide | |||||
| Octenidine | Cationic surfactant | Binds to cell envelope; Interaction with enzymes and polysaccharides in the cell envelope; induces leakage in the cytoplasmic membrane | Antiseptic for skin disinfection and wound treatment | 1 | 0.8 (0.3) |
| Benzalkonium chloride (BAC) | Cationic quaternary ammonium compound | Interacts with cell membranes, leading to disruption of membrane integrity and leakage of cellular content | Antiseptic ointments, drops, creams and sprays; antimicrobial coatings | 25 | 21.4 (0.8) |
| Cetrimonium bromide (CTAB) | Cationic quaternary ammonium compound | Binding to lipid components of the cell membrane, causing membrane rupture and cell lysis | Antimicrobial coating and topical antiseptic in hygiene and pharmaceuticals | 16 | 13.3 (0.8) |
| Chlorhexidine | Cationic biguanide | Binds to negatively charged bacterial walls, causing membrane disruption and leakage | Topical skin disinfectants, wound and burn dressings, coating of catheters | 7.6 | 5.6 (0.2) |
| Povidone-iodine (PVP-I) | Halogen | Rapidly penetrates microorganisms, damaging proteins, nucleotides and fatty acids | Disinfectant in wound dressings | 150 | 138 (5) |
| Silver nitrate (AgNO3) | Transition metal | Ability to bind FeS-clusters or thiol-groups of enzymes, inhibiting cellular functions such as electron transport chain; ROS formation | Topical antiseptic on moist skin, mucous and skin wounds | 0.01 | 0.0058 (0.0006) |
| Silver nanoparticles (AgNP) | Transition metal | Similar to AgNO3 | Antimicrobial coating on medical devices | 0.03 | 0.026 (6.8) |
*
MIC and EC50 measured in M9 medium, concentration in μg ml−1.
#
The brackets depict the standard error of the simultaneous dose-response fit of three biological replicates scaled with the square route of the reduced χ2.