Decreased Competiveness of the Foodborne Pathogen Campylobacter jejuni during Co-Culture with the Hyper-Ammonia Producing Anaerobe Clostridium aminophilum

Campylobacter spp. are a leading bacterial cause of human foodborne illness. When co-cultured in anaerobic Bolton broth with the hyper-ammonia producing bacterium, Clostridium aminophilum, ammonia accumulation was greater and final growth of Campylobacter jejuni was reduced (CFU >= 1.4 log(10)/mL) compared to that obtained by pure culture controls. Co-culture with the less active ammonia-producing saccharolytic Prevotella albensis had no effect on final C. jejuni concentrations. When co-cultured similarly except with the addition of 10 mu mol/L monensin, monensin-susceptible Cl. aminophilum was reduced by 2 to 4 log(10) CFU/mL and concentrations of C. jejuni, which is insensitive to monensin, did not differ from its pure culture control. These results suggest that in the absence of added monensin, the hyper ammonia-producing Cl. aminophilum may be able to outcompete asaccharolytic C. jejuni for amino acid substrates and that this competitive ability was eliminated by addition on monensin.