Nature Microbiology, Published online: 31 August 2026; doi:10.1038/s41564-026-02461-w The journey of Mycobacterium tuberculosis between hosts in aerosol droplets has often been viewed as a passive phase in its life cycle. Recent evidence shows that the inevitable desiccation associated with aerosol transmission triggers a program that imperfectly repairs DNA damage, generating genetic diversity and increased recovery of antibiotic-resistant mutants.