Survival of Campylobacter jejuni during in vitro culture with mixed bovine ruminal microorganisms in the presence of methanogen inhibitors

Abstract

Foodborne pathogen Campylobacter jejuni has been associated with ruminants. The objectives of this experiment were to determine C. jejuni survivability in mixed in vitro rumen microbial populations and the impact on methane production with or without methane inhibitors 2-bromosulfonate (BES) and/or sodium nitrate. When inoculated into rumen microbial populations without or with 0.5 mM BES, 5.0 mM nitrate or their combination, C. jejuni viability decreased from 4.7 ± 0.1 log₁₀ colony forming units (CFU)/mL after 24 h. Loss of C. jejuni viability was greater (P < 0.05) when incubated under 100% CO₂ compared to 50% H₂:50% CO₂, decreasing 1.46 versus 1.15 log units, respectively. C. jejuni viability was also decreased (P < 0.05) by more than 0.43 log units by the anti-methanogen treatments. Rumen microbial populations produced less methane (P = 0.05) when incubated with than without C. jejuni regardless of whether under 100% CO₂ or 50% H₂:50% CO₂. For either gas phase, nitrate was decreased (13.2 versus 37.9%) by the anti-methanogen treatments versus controls although not always significant. C. jejuni-inoculated populations metabolized 16.4% more (P < 0.05) nitrate under H₂:CO₂ versus 100% CO₂. Apparently, C. jejuni can compete for H₂ with methanogens but has limited survivability under rumen conditions.

Keywords:

• Campylobacter jejuni
• methane
• in vitro rumen incubations
• sodium nitrate
• 2-bromosulfonate

Data availability

The data that support the findings of this study are available from the corresponding author [SCR], upon reasonable request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.