Assessing the antimetabolite activity of modified vitamin B12 analogues against Lactobacillus delbrueckii and Listeriamonocytogenes.

Developing novel strategies against foodborne pathogens, like Listeria monocytogenes , is crucial due to their growing resistance to current hurdles and disinfection protocols. Disruption of the cobalamin biosynthesis pathway revealed the importance of vitamin B 12 (B 12) in L. monocytogenes tolerance to cold and copper stress, suggesting that B 12 analogues have potential as hurdles against it on food. In 2021, 10-Br-methyl cobalamin (10-Br-MeCbl) was introduced as an L. monocytogenes antimetabolite. Herein, we re-evaluated 10-Br-MeCbl and tested seven related B 12 analogues against six L. monocytogenes strains and a B 12 auxotrophic Lactobacillus delbrueckii strain. No analogue, including 10-Br-MeCbl, was inhibitory to L. monocytogenes. In contrast, 10-Br-MeCbl, 10-Br-CNCbl, 10-Br-PhCbl, and 10-Br-CNCbl- c -lactam inhibited L. delbrueckii growth (13–27%) at concentrations 50-folds higher than B 12. This inhibitory activity was lost under conditions of B 12 abundance, indicating competitive inhibition. The activity of phenylcobalamin- c -lactam against L. delbrueckii differed compared to a previous study, emphasizing that the antimicrobial activity of B 12 derivatives is not universal and must be examined for each species under the application conditions. Overall, while this study illustrates the potential of B 12 antimetabolites as antimicrobials, it also demonstrates that other classes of B 12 antimetabolites and/or improved strategies are required for tackling pathogens like L. monocytogenes. • Novel strategies are needed to combat foodborne pathogens. • No tested B 12 analogue, including 10-Br-MeCbl, inhibited L. monocytogenes. • Four B 12 analogues inhibited L. delbrueckii at concentrations 50 times that of B 12. • B 12 analogues might act on L. delbrueckii through competitive inhibition. • B 12 analogue inhibitory action is species-based, necessitating specific-validation. [ABSTRACT FROM AUTHOR]