GENEVA-The rise of superbugs, stoked by misuse of antibiotics and shoddy hospital hygiene, is enabling long-treatable diseases to once again become killers, the World Health Organization warned on Wednesday. In a hard-hitting study of antimicrobial resistance - when bacteria adapt so that existing drugs no longer beat them - the UN health agency said the issue was a global emergency and urged all players to wake up. Without urgent, coordinated action by many stakeholders, the world is headed for a post-antibiotic era, in which common infections can once again kill.