ATLANTA - More than 1 million cases of chlamydia were reported in the United States last year — the most ever reported for a sexually transmitted disease, federal health officials said Tuesday. ADVERTISEMENT Officials at the Centers for Disease Control and Prevention said they think better and more intensive screening accounts for much of the increase, but added that chlamydia was not the only sexually transmitted disease on the rise. Gonorrhea rates are jumping again after hitting a record low, and an increasing number of cases are caused by a "superbug" version resistant to common antibiotics.