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

Abstract

Campylobacter jejuni 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 Campylobacter. In addition to a role in multidrug resistance (MDR), the Campylobacter CmeABC resistance-nodulation-division (RND)-type efflux pump may be involved in virulence. As a vehicle for pathogenic microorganisms, the protozoan Acanthamoeba is a good model for investigations of bacterial survival in the environment and the molecular mechanisms of pathogenicity. The interaction between C. jejuni 81-176 and Acanthamoeba polyphaga 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 C. jejuni in A. polyphaga but is dispensable for biofilm formation and motility.IMPORTANCE 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 Campylobacter jejuni was able to survive and to multiply inside Acanthamoeba polyphaga; since these microorganisms can coexist in the same environment (e.g., on poultry farms), the latter may increase the risk of infection with Campylobacter. 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 C. jejuni, the CmeABC MDR efflux pump could be considered a good target for the development of antibacterial drugs against this pathogen.

Adhesion of Campylobacter jejuni Is Increased in Association with Foodborne Bacteria

“…The adhesion of C. jejuni was similar to that previously observed [27], although Campylobacter biofilms, biomass, and ultrastructure differ between strains [29]. In the present study, the adhesion of C. jejuni to polystyrene was higher than seen for adhesion to the Caco-2 cells and A. castellanii.…”

“…Prolonged incubations (24-96 h) resulted in more than 80% of the C. jejuni inside these intracellular vacuoles. Vieira et al described the contribution of a Campylobacter efflux pump to bacterial survival within amoebae [29]. In the present study with A. castellanii, <0.01% of the viable C. jejuni cells were internalized after 2 h of incubation with A. castellanii.…”

Dual Role of Mechanisms Involved in Resistance to Predation by Protozoa and Virulence to Humans

“…Efflux systems are also involved in antibiotic resistance. For example, the C. jejuni RND-type efflux pump, CmeABC which is associated with multidrug resistance, may also be involved in virulence as well as survival in A. polyphaga ( Vieira et al, 2017 ). These data highlight the role of these “virulence factors” in persistence and survival in the environment and likely evolved to protect bacteria from predation rather than for protection against antibiotics, given the long history of co-evolution of protozoa and bacteria.…”

In Vitro Effect of the Common Culinary Herb Winter Savory (Satureja montana) against the Infamous Food Pathogen Campylobacter jejuni

“…C. jejuni resistance nodulation division (RND) efflux pumps CmeABC and CmeDEF, and the major facilitator superfamily (MFS) efflux pump CmeGH are great contributors to these resistances. These efflux pumps and their overexpression cause resistance against antibiotics, such as erythromycin and ciprofloxacin, heavy metals, and bile acids, although, even without overexpression they can confer other resistance determinants for greater antibiotic and stress resistance in C. jejuni [6][7][8][9]. The inhibition of the major efflux pumps can thus lead to increased C. jejuni susceptibility to antimicrobials [6].…”