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

Authors: DITTOE, DANA - University Of Wisconsin; Anderson, Robin; KRUEGER, NATHAN - Blinn College; Harvey, Roger; Poole, Toni; Crippen, Tawni - Tc; CALLAWAY, TODD - University Of Georgia; RICKIE, STEVEN - University Of Wisconsin

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2023
Publication Date: 10/28/2023
Citation: Dittoe, D.K., Anderson, R.C., Krueger, N.A., Harvey, R.B., Poole, T.L., Crippen, T.L., Callaway, T.R., Rickie, S.C. 2023. Survival of Campylobacter jejuni during in vitro culture with mixed bovine ruminal microorganisms in the presence of methanogen inhibitors. Journal of Environmental Science and Health. 58(12):711-717. https://doi.org/10.1080/03601234.2023.2273754.
DOI: https://doi.org/10.1080/03601234.2023.2273754

Interpretive Summary: A bacterium named Campylobacter jejuni is the leading bacterial cause of human foodborne illness in the United States. While highly pathogenic to humans, this bacterium harmlessly inhabits the gastrointestinal tract of chickens, pigs, sheep, and cattle and can be a major source of contamination for meat and milk during processing. Strategies are sought to prevent Campylobacter jejuni from colonizing the animal gut, as it is recognized that this can help reduce the incidence of human food poisoning. In cattle, Campylobacter jejuni is known to colonize in the small and large intestinal tract with greater efficiency than in the animal's pre-gastric rumen compartment, but it is not known why this occurs. The rumen, where ingested feed first arrives, is prone to leakage during processing and this leakage may be a greater risk for carcass contamination. As part of our ongoing effort to develop strategies to rid Campylobacter jejuni from the gut of cattle, we conducted a study to learn more about how Campylobacter jejuni survives in the gut environment. Results from our study revealed that Campylobacter jejuni can successfully compete against gut microbes that use hydrogen as a growth-supporting nutrient. This important new information may ultimately help us learn how to limit the growth of Campylobacter jejuni in the gut of cattle, thereby improving the microbiological safety of meat and milk produced for the American consumer.

Technical Abstract: Foodborne pathogen, Campylobacter infection, is the leading bacterial cause of human foodborne illness in the United States. The objectives of this experiment were to determine if Campylobacter jejuni could survive in the presence of mixed microbial populations from the bovine rumen and the impact on methane production with or without methane inhibitors 2-bromosulfonate (BES) and/or sodium nitrate. C. jejuni was inoculated in rumen fluid without or with 0.02 mL 24 mM BES, 0.2 mL 250 mL sodium nitrate or an equivalent of water to yield tubes containing 0, 0.05 mM 2-BES, 0.5 mM sodium nitrate, or their combination under a 100% carbon dioxide gas phase. In mixed rumen culture incubations, interactions between C. jejuni inoculation and anti-methanogenic treatments were observed on amounts of methane produced (P = 0.0482) and nitrate metabolized. Methane production was highest in those treated with 0.5 mM sodium nitrate but not inoculated with C. jejuni, lowest in the C. jejuni-inoculated populations treated with the combination of 5 mM sodium nitrate and 0.05 mM 2-bromosulfonate (2.34). Metabolized nitrate was lower in the mixed rumen populations inoculated with C. jejuni and treated with the combination of 5 mM sodium nitrate and 0,05 mM 2-bromosulfonate than in the other treated cultures, which ranged from 3.58 to 3.83 umol/mL. It appears that C. jejuni can compete for hydrogen with methanogens but has limited ability to survive under rumen conditions.