The molecular mechanisms of quinolone resistance in Salmonella: a review

Salmonella is an important foodborne pathogen, and its quinolone resistance poses a considerable threat to public health. This review comprehensively analyzes various quinolone resistance mechanisms of Salmonella, including mutations in genes encoding drug targets, export of quinolones by efflux pump systems, decrease in Salmonella cell permeability, and the formation of special physiological states. The gyrA and parC are two important genes encoding the drug targets of quinolones, and their genetic mutations result in the drug targets being unable to be recognized by quinolones. Many efflux pumps, such as AcrAB, MdtABC, MdsABC, EmrAB, etc., transport quinolones out of Salmonella cells. A reduction in the expression of some porins decreases quinolone permeability, further aggravating drug resistance. In addition, special physiological states of Salmonella, such as a low metabolic state, biofilms, and quorum sensing, significantly increase quinolone resistance of Salmonella. The development of quinolone resistance in Salmonella is a complex process involving the synergistic effects of multiple mechanisms.