Antibiotic-resistant bacteria, known as ‘superbugs,’ pose a major public health threat. Some officials have even warned of a post-antibiotic — and sicker — era. To better understand the problem, researchers have been piecing together its contributing factors. Now, scientists report for the first time a link between antimicrobial substances such as triclosan in indoor dust and levels of antibiotic-resistance genes, which can transfer from one bacterial cell to another.