Bacterial communication in the gut: interbacterial and bacteria-host crosstalk

The human gut harbors a complex ecosystem in which bacteria engage in interbacterial and bacteria-host communication through diverse molecular languages to orchestrate collective behaviors and host interactions. This review explores the principal mechanisms and mediators of bacterial communication in the gut, with a focus on three central processes: horizontal gene transfer, which facilitates genomic plasticity; bacterial extracellular vesicle-mediated cargo delivery; and quorum sensing, which enables transcriptional regulation in response to population density. These systems support the exchange of nucleic acids, signaling molecules, and functional proteins, thereby promoting both cooperative and competitive interactions among bacteria and host cells. We further discuss how these communication pathways collectively influence bacterial evolution, community stability, and host health, playing roles in both maintaining homeostasis and contributing to disease. Elucidating these interactions provides valuable insights into microbiome-associated disorders and opens avenues for novel therapies aimed at modulating bacterial crosstalk in the gut.