Environmental selection and vertical inheritance shape antibiotic resistance in cryospheric bacteria on the Tibetan Plateau

Antibiotic resistance genes (ARGs) occur even in remote cryospheric regions, yet their environmental selection mechanisms, distribution, and risks remain unclear. Here, 45% of 920 bacterial strains from Tibetan Plateau ice cores, cryoconites, snow, and lakes carry ARGs, with prevalence and diversity varying across habitats, reflecting distinct environmental pressures. Snow-derived ARGs reflect atmospheric deposition, whereas ice cores preserve resistance via genome recycling. Organic- and heavy metal-rich cryoconites promote ARG acquisition and persistence, while lakes reduce ARG abundance through natural attenuation. Strains of the same species exhibit consistent ARG profiles, and only 6.4% of ARGs are associated with mobile genetic elements, indicating that vertical inheritance predominates. Thirty-three high-risk ARG subtypes were identified, including several in potentially pathogenic genera. Tibetan strains carry fewer ARGs than those from human-impacted sites. This large-scale, culture-based resistome survey identifies the Tibetan Plateau as a natural baseline and highlights potential ARG mobilization risks under environmental change. 45% of 920 of cryospheric bacterial strains from Tibetan Plateau carry antibiotic-resistance genes with habitat-specific patterns, with 6.4% linked to mobile genetic elements, suggesting vertical inheritance in low-selection environments, based on analysis of strains from distinct habitats.