The Binding of Triclosan to SmeT, the Repressor of the Multidrug Efflux Pump SmeDEF, Induces Antibiotic Resistance in Stenotrophomonas maltophilia
Figure 8
Effect of triclosan on the susceptibility to antibiotics of S. maltophilia.
Panel A: In the basal state, SmeT (orange circles) is bound to its cognate operator DNA repressing the transcription of smeDEF. The fact that damage is caused by ciprofloxacin (yellow stars) inside the bacteria is represented by crinkly arrows. Panel B: The entrance of triclosan (black spots) causes bacterial damage and, simultaneously, the binding of the biocide to SmeT releases the protein from its operator allowing high-level transcription of smeDEF. Once the pump is expressed, its substrates - triclosan and ciprofloxacin - are pumped out of the bacteria. However the toxic effect of triclosan prevents the cells reaching the level of resistance observed in a mutant defective in SmeT (see text for more details).