Virulent C. difficile outbreaks worry experts.(News)

LOS ANGELES -- Discussion about the spread of a highly toxic new strain of Clostridium difficile dominated a recent meeting of infectious disease specialists and hospital epidemiologists, who cautioned that widespread reports of the aggressive nosocomial infection might be just the tip of the iceberg.

"We're at the beginning of an era of a more virulent strain in North America, leading to graver illness and sequelae, including colectomy and even death," said Leonard Mermel, D.O., professor of medicine at Brown University in Providence, R.I., at the annual meeting of the Society for Healthcare Epidemiology of America.

"This should cause pause for practicing physicians," Dr. Mermel, SHEA president.

Sharply increased rates of C. difficile infection have been reported nationwide since 2000, with the new epidemic strain currently isolated to nine states: Connecticut, Florida, Georgia, Illinois, Maine, New Jersey, Ohio, Oregon, and Pennsylvania. It has also been reported in Canada.

Any patient who has been prescribed antibiotics is potentially at risk for C. difficile infection, long recognized as an unintended consequence of disrupting the normal flora within the colon.

Historically, clindamycin has been recognized as a culprit; the condition was once referred to as "clindamycin-induced colitis," said L. Clifford McDonald, M.D., who is a medical epidemiologist in the Division of Healthcare Quality Promotion of the Centers for Disease Control and Prevention.

But other antibiotics have been implicated, as well. "Right now we're concerned about fluoroquinolones, since a number of recent outbreaks have involved fluoroquinolone use," Dr. McDonald said in an interview following the annual meeting of the Society for Healthcare Epidemiology of America.