A mysterious adversary preys on the war's wounded

The young Army medic would not stop bleeding.

He had been put on a powerful regimen of antibiotics by doctors aboard the hospital ship Comfort in the Persian Gulf. But something was wrong.

He was in shock and bleeding from small pricks where nurses had placed intravenous lines. Red, swollen tissue from an active bacterial infection was expanding around his abdominal wound. His immune system was in overdrive.

How odd, thought Dr. Kyle Petersen, an infectious disease specialist. He knew of one injured Iraqi man with similar symptoms and a few days later encountered an Iraqi teenager with gunshot wounds in the same condition.

Within a few days, blood tests confirmed that the medic and the two wounded Iraqis were all infected with an unusual bacterium, Acinetobacter baumannii.

This particular strain had a deadly twist. It was resistant to a dozen antibiotics. The medic survived, but by the time Petersen connected the dots, the two Iraqi patients were dead.

It was April 2003, early in the Iraq war -- and 4 1/2 years later, scientists are still struggling to understand the medical mystery.

The three cases aboard the Comfort were the first of a stubborn outbreak that has spread to at least five other American military hospitals, including Walter Reed Army Medical Center in Washington and the Army's Landstuhl Regional Medical Center in Germany.

Hundreds of patients -- the military says it has not tabulated how many -- have been infected with the bacterium in their bloodstream, cerebrospinal fluid, bones or lungs. Many of them were troops wounded in Iraq or Afghanistan; others have been civilians infected after stays in military hospitals.

At least 27 people have died in military hospitals with Acinetobacter infections since 2003, although doctors are uncertain how many of the deaths were caused by the bacteria.

The rise in infections has been dramatic. In 2001 and 2002, Acinetobacter infections made up about 2% of admissions at the specialized burn unit at Brooke Army Medical Center in Texas. In 2003, the rate jumped to 6%, and then to 12% by 2005. Other military hospitals have reported similar increases.

In the early days of the war, there were so many infections in an intensive care unit on the Comfort that a nurse posted a sign: "Acinetobacter Alley." In two months, the bacterium was found in 44 of the 211 patients wounded in battle.

It was getting out of control. Petersen pleaded for help on an infectious disease mailing list.