ARS | Publication request: Effect of H2 on culture of Campylobacter jejuni within mixed populations of ruminal bacteria

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2010
Publication Date: June 23, 2010
Citation: Anderson, R.C., Krueger, N.A., Callaway, T.R., Harvey, R.B., Nisbet, D.J. 2010. Effect of H2 on culture of Campylobacter jejuni within mixed populations of ruminal bacteria [abstract]. Rowett-INRA. p. 80.

Technical Abstract: Campylobacter jejuni is a leading bacterial cause of human foodborne illness. Campylobacter readily colonize the gut of food animals as evidenced by prevalence rates often exceeding 80%. Physiologically, C. jejuni conserve energy via amino acid catabolism and anaerobic respiration. Hydrogen is reported to be stimulatory to the growth of C. jejuni during pure culture with microaerobic O2 concentrations, but we questioned whether H2 would be stimulatory during culture within mixed populations of gut bacteria where availability of reducing substrates and electron acceptors may be limited. When inoculated and cultured 24 h in freshly collected ruminal fluid, initially under 100% CO2 and with 0.7 g l-1 added casamino acids, mean specific growth rates of C. jejuni were unaffected by treatment with 0.06 mM 2-bromoethane sulfunoic acid (BES)(0.16 versus 0.13 for cultures treated with or without BES, respectively; SEM=0.02). The BES was added to inhibit H2 consumption by methanogens, and as expected, promoted higher H2 (P<0.05) and lower CH4 (P<0.05) accumulation than in the non-BES-supplemented cultures (5.7% versus 1.2% H2, and 4.8% versus 20.1% CH4, respectively; SEM=0.78 and 0.82). When cultured similarly except with unnaturally high H2 (50% H2 in CO2), growth rates of C. jejuni were greater (P<0.05) than rates obtained during culture under 100% CO2 (0.36 versus 0.15, respectively; SEM=0.02). Rates again were unaffected by BES. We conclude that with the limited availability of electron acceptors in the gut, it is unlikely that H2 concentrations would be high enough to markedly affect growth of C. jejuni.