A gene that strips away one of the last reliable classes of antibiotics is no longer a rarity imported from overseas. It is showing up in more American hospitals, and new wastewater data suggest it is also circulating in some communities outside of them. Why a Gene Spreads Differently Than a BacteriumMost hospital outbreak investigations look for one organism moving between patients. It is a gene that makes bacteria resistant to carbapenems, a class of last-resort antibiotics, and often to other antibiotics as well. An outbreak can involve several different bacteria sharing the same resistance gene, which standard hospital surveillance is not designed to detect.