TABLE 11.
qac genes and resistance to quaternary ammonium compounds and other antiseptics and disinfectants
| Multidrug resistance determinanta | Gene location | Resistance encoded to |
|---|---|---|
| qacA | pSK1 family of multiresistant plasmids, also β-lactamase and heavy-metal resistance families | QACs, chlorhexidine salts, diamidines, acridines, ethidium bromide |
| qacB | β-Lactamase and heavy-metal resistance plasmids | QACs, acridines, ethidium bromide |
| qacCb | Small plasmids (<3 kb) or large conjugative plasmids | Some QACs, ethidium bromide |
| qacDb | Large (50-kb) conjugative, multiresistance plasmids | Some QACs, ethidium bromide |
a
The qacK gene has also been described, but it is likely to be less significant than qacAB in terms of antiseptic or disinfectant tolerance.
b
These genes have identical target sites and show restriction site homology.