Akkermansia muciniphila reduces diet-induced susceptibility to Listeria monocytogenes infection

A high fat (HF) diet decreases levels of <em>Akkermansia muciniphila</em> in the gut and reduces resistance to the foodborne pathogen <em>Listeria monocytogenes</em>. We demonstrate that short-term gavage with <em>A. muciniphila</em> increases resistance to oral and systemic <em>L. monocytogenes</em> infection in mice fed a HF diet. <em>A. muciniphila</em> normalized diet-induced inflammation in the gut and liver prior to infection and reduced inflammatory cell infiltration in the ileum to levels similar to mice fed a low fat diet. <em>A. muciniphila</em> administration had minimal impact upon the microbiota and microbial metabolites and did not affect individual taxa or impact the Bacteroidetes to Firmicutes ratio. In summary, <em>A. muciniphila</em> increased resistance to <em>L. monocytogenes</em> infection in mice fed a HF diet, through normalising immune/physiological effects that more closely resembled mice fed a LF diet. The findings suggest an interaction between <em>A. muciniphila</em> and the host to reverse the effects of a westernized diet in this model.