NEW YORK (AP) — One type of superbug bacteria is increasingly spreading among people who inject drugs, according to a new government report. Users of heroin and other injection drugs were 16 times more likely than other people to develop severe illnesses from MRSA, said the report published Thursday. "Drug use has crept up and now accounts for a substantial proportion of these very serious infections," said Dr. William Schaffner of Vanderbilt University, one of the study's authors.