What is a 'superbug' and why do people catch it?

It shouldn't happen — someone goes into the hospital to get better and instead comes out with a potentially deadly "superbug" infection. The latest big case involves the UCLA health system, which is warning 160 or more patients that they may have been given a procedure using equipment contaminated with bacteria called carbapenem-resistant Enterobacteriaceae or CRE. Seven patients were infected and two of them, already seriously ill, died. Here are some questions and answers about CRE. CRE refers to a family of drug-resistant bacteria. They've evolved so that most antibiotics cannot kill them, making them into what are known as superbugs.