The ability of probiotic strain Escherichia coli O83:K24:H31 to modulate gut homeostasis and immune function after antibiotic-induced dysbiosis

A healthy microbiome and a homeostatic interaction between the microbiome and the host immune system are essential for proper nutrition and overall health. Excessive use of antibiotics (ATB) can disrupt the healthy gut microenvironment, leading to dysbiosis, a condition linked to a wide range of disorders and diseases. Alterations in the composition and function of the microbiota have been associated with a broad spectrum of various pathological conditions In this work, we investigate the effect of ATB administration on microbiota composition and immune modulation, with a particular focus on neutrophil dynamics. We evaluated the capacity of the probiotic strain Escherichia coli O83:K24:H31 (EcO83) to mitigate ATB-induced dysbiosis and restore immune function. As expected, ATB treatment reduced microbiota diversity, which was partially restored by EcO83 supplementation. Furthermore, ATB administration affected the expression of tight junction proteins in the small intestine, an effect reversed by EcO83 treatment. Notably, our data indicates that ATB-induced dysbiosis accelerates neutrophil aging and reduces the release of neutrophils from the bone marrow. EcO83 supplementation counteracts these effects by promoting the influx of newly generated neutrophils into circulation. Overall, our findings confirm that ATB treatment disrupts gut microbiota homeostasis, adversely affecting immune function, including neutrophil turnover. However, probiotic supplementation with EcO83 can at least partially restore microbiome composition and immune homeostasis, highlighting its potential therapeutic application in mitigating ATB-induced dysbiosis.