ARS | Publication request: Decreased competiveness of the foodborne pathogen, Campylobacter jejuni, co-culture with the hyper-ammonia anaerobe, Clostridium aminophilum

Submitted to: Folia Microbiologica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2010
Publication Date: July 14, 2010
Citation: Anderson, R.C., Flythe, M.D., Krueger, N.A., Callaway, T.R., Edrington, T.S., Harvey, R.B., Nisbet, D.J. 2010. Decreased competitiveness of the foodborne pathogen, Campylobacter jejuni, co-culture with the hyper-ammonia anaerobe, Clostridium aminophilum. Folia Microbiologica. 55:309-311.

Interpretive Summary: Campylobacter jejuni is an important pathogenic bacterium that can reside within the gastrointestinal tract of food-producing animals such as cattle, swine, and chickens. Unlike most other bacteria that inhabit the gut, Campylobacter jejuni is not able to metabolize sugar-containing compounds to obtain energy for growth. Rather, Campylobacter jejuni obtains energy by degrading amino acid-type compounds that are produced in the gut during the digestion of protein. We report here results from an experiment conducted to test if another non-pathogenic amino acid-using bacterium, Clostridium aminophilum, could outcompete Campylobacter by being better at utilizing amino acids as energy sources. We found that when cultured together, the non-pathogenic bacterium, Clostridium aminophilum, was indeed able to outcompete Campylobacter jejuni, reducing growth of the latter pathogenic bacterium more than 10-fold compared to growth achieved when it was grown by itself. These results may ultimately help farmers and ranchers eliminate Campylobacter jejuni from the gut of farm animals and thereby produce microbiologically safer meat and milk products for the American consumer.

Technical Abstract: 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 (P < 0.05) and final growth of Campylobacter jejuni was reduced (P < 0.05) > 1.4 log10/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 Camp. jejuni concentrations. When co-cultured similarly, except with the addition of 0.01 mM monensin, monensin-susceptible Cl. aminophilum was reduced (P < 0.05) by 2 to 4 log10 CFU/mL, and concentrations of Camp. 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 Camp. jejuni for amino acid substrates and that this competitive ability was eliminated by addition on monensin.