CmeABC Multidrug Efflux Pump Contributes to Antibiotic Resistance and Promotes Campylobacter jejuni Survival and Multiplication in Acanthamoeba polyphaga.

is a foodborne pathogen that is recognized as the leading cause of human bacterial gastroenteritis. The widespread use of antibiotics in medicine and in animal husbandry has led to an increased incidence of antibiotic resistance in In addition to a role in multidrug resistance (MDR), the CmeABC resistance-nodulation-division (RND)-type efflux pump may be involved in virulence. As a vehicle for pathogenic microorganisms, the protozoan is a good model for investigations of bacterial survival in the environment and the molecular mechanisms of pathogenicity. The interaction between 81-176 and was investigated in this study by using a modified gentamicin protection assay. In addition, a possible role for the CmeABC MDR pump in this interaction was explored. Here we report that this MDR pump is beneficial for the intracellular survival and multiplication of in but is dispensable for biofilm formation and motility. The endosymbiotic relationship between amoebae and microbial pathogens may contribute to persistence and spreading of the latter in the environment, which has significant implications for human health. In this study, we found that was able to survive and to multiply inside ; since these microorganisms can coexist in the same environment (e.g., on poultry farms), the latter may increase the risk of infection with Our data suggest that, in addition to its role in antibiotic resistance, the CmeABC MDR efflux pump plays a role in bacterial survival within amoebae. Furthermore, we demonstrated synergistic effects of the CmeABC MDR efflux pump and TetO on bacterial resistance to tetracycline. Due to its role in both the antibiotic resistance and the virulence of , the CmeABC MDR efflux pump could be considered a good target for the development of antibacterial drugs against this pathogen.