TABLE 9.
Possible mechanisms of plasmid-encoded resistance to antiseptics and disinfectants
| Chemical agent | Examples | Mechanisms |
|---|---|---|
| Antiseptics or disinfectants | Chlorhexidine salts | (i) Inactivation: not yet found to be plasmid mediated; chromosomally mediated inactivation; (ii) efflux: some S. aureus, some S. epidermidis; (iii) Decreased uptake(?) |
| QACs | (i) Efflux: some S. aureus, some S. epidermidis; (ii) Decreased uptake(?) | |
| Silver compounds | Decreased uptake; no inactivation (cf. mercury compounds) | |
| Formaldehyde | (i) Inactivation by formaldehyde dehydrogenase; (ii) Cell surface alterations (outer membrane proteins) | |
| Acridinesa | Efflux: some S. aureus, some S. epidermidis | |
| Diamidines | Efflux: some S. aureus, some S. epidermidis | |
| Crystal violeta | Efflux: some S. aureus, some S. epidermidis | |
| Other biocides | Mercurialsb | Inactivation (reductases, lyases) |
| Ethidium bromide | Efflux: some S. aureus, some S. epidermidis |
a
Now rarely used for antiseptic or disinfectant purposes.
b
Organomercurials are still used as preservatives.