Gut and faecal microbiota alterations in mice following infection with Arcobacter butzleri strains from a food processing plant.

Arcobacter butzleri is a foodborne pathogen associated with gastrointestinal disorders in humans. Its antibiotic resistance is well documented, and in vitro studies have shown its ability to colonise and invade human cell lines. Murine models are essential for integrating host immune responses and gut microbiota dynamics in infection studies. This study aimed to evaluate the pathogenicity and infectivity of A. butzleri strains using a murine model, focusing on invasion mechanisms and impact on intestinal microbiota. Fifteen Mus musculus C57BL/6J mice were orally infected with 8.5 Log CFU/ml of two strains. Faecal samples were collected before infection and over 14 days, while organs were analysed post-mortem. Infection was assessed using culture-dependent and culture-independent methods to study microbiota alterations. Molecular analyses confirmed the presence of A. butzleri in faecal samples until day 4. Beta-diversity analyses revealed significant differences in colonic microbiota between mice infected with the two strains. The duodenal microbiota was dominated by Paramuribaculum, Duncaniella, Dubosiella, and Muribaculum, whereas Akkermansia, Duncaniella, and Paramuribaculum were most prevalent in colonic and faecal samples. A. butzleri persisted under gastrointestinal conditions, a key feature for foodborne pathogens. Alterations in host microbiota were strongly associated with infection, emphasizing the critical role of microbial dynamics in A. butzleri pathogenesis.