The deadly superbug, Clostridioides difficile (C. diff), is putting up a winning fight against hospital-grade disinfectants meant to kill it, reports a pharmacy professor in a study that helps explain why C. diff is so hard to eradicate. The survival of C. diff in hospitals and nursing homes is especially hazardous — within one month of diagnosis, one in 11 people over age 65 died of a health care-associated C. diff infection.