Intravacuolar persistence in neutrophils facilitates <i>Listeria monocytogenes</i> spread to co-cultured cells

<i>Listeria monocytogenes</i> (<i>Lm</i>) is a significant foodborne pathogen responsible for high hospitalization rates in humans, especially vulnerable groups such as the elderly, pregnant women, and immunocompromised individuals. In animals like ruminants, <i>Lm</i> infection leads to severe disease manifestations, notably brainstem encephalitis. This study uncovers a novel mechanism by which bovine neutrophils (PMNs) harbor <i>Lm</i> in a viable but non-culturable (VBNC) state, enabling the bacteria to hide in the host. PMNs, traditionally viewed as bacteria killers, may serve as Trojan horses, allowing <i>Lm</i> to persist and spread within the host. This discovery has broad implications for understanding <i>Lm</i>'s persistence, its role in recurrent infections, and the development of new therapeutic strategies targeting VBNC forms of <i>Lm</i> to improve treatment outcomes and disease control.