Antimicrobial resistance (AMR) poses a critical threat to global health, driven by the extensive use of antibiotics in both human medicine and livestock production. In the context of the One Health framework, this review investigates the role of the gut microbiome and resistome, which represents the collection of antimicrobial resistance genes (ARGs), within livestock and among occupationally exposed workers. Intensive farming practices often involve routine, subtherapeutic antibiotic use, fostering antibiotic-resistant bacteria (ARB) in the gastrointestinal tract of animals. These ARB and ARGs are excreted into the environment, contributing to resistance spread through mobile genetic elements. From a Planetary Health perspective, this environmental dissemination reflects how human-driven livestock practices can perturb ecosystems, creating global health risks that link animal, human, and environmental well-being. Human exposure, particularly among farm workers and veterinarians, raises significant concerns about zoonotic transmission of pathogens and, potentially, ARB. Novel advances in metagenomic and metatranscriptomic technologies enhanced our understanding of gut microbial communities and their resistomes, revealing overlaps in ARG profiles between animals and livestock workers. These technologies also support the development of novel microbiome-targeted strategies, including prebiotics, probiotics, food supplementation and workplace-improvement strategies, aimed at reducing antimicrobial use and restoring healthy microbiome balance. The review also highlights the importance of integrated surveillance and cross-sectoral collaboration to monitor and control AMR transmission. Understanding the ecological dynamics of the gut resistome in livestock systems is essential for designing effective interventions that safeguard both animal and human health.
Keywords: antimicrobial resistance; gut microbiome; livestock farming; one health; resistome.
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