Use of antibiotics at U.S. hospitals is rising despite concerns about fueling bacterial resistance, with Wyeth's Zosyn and the older drug vancomycin driving the trend, researchers said. Use of antibiotics at a group of U.S. academic medical centers rose 7% from 2002 to 2006, Ronald Polk of Virginia Commonwealth University and colleagues reported in the journal Archives of Internal Medicine. As doctors prescribe more antibiotics, experts are alarmed that drugs that once killed the germs no longer do so, meaning an illness may last longer and be more likely to be fatal.