An unexpectedly high number of U.S. soldiers injured in the Middle East and Afghanistan are testing positive for a rare, hard-to-treat blood infection in military hospitals, Army doctors reported on Thursday.

A total of 102 soldiers were found to be infected with the bacteria Acinetobacter baumannii. The infections occurred among soldiers at Walter Reed Army Medical Center in Washington, Landstuhl Regional Medical Center in Germany and three other sites between Jan. 1, 2002, and Aug. 31, 2004.

Although it was not known where the soldiers contracted the infections, the Army said the recent surge highlighted a need to improve infection-control in military hospitals.

Eighty-five of the bloodstream infections occurred among soldiers serving in Iraq, the area around Kuwait and Afghanistan, the U.S. Army said in a report published on Thursday by the Centers for Disease Control and Prevention.

Military hospitals typically see about one case per year.

Army investigators said they did not know whether the soldiers contracted the infections on the battlefield, during medical treatment on the front line or following evacuation to Walter Reed, Landstuhl and other military medical locations.

“Although some of the patients identified in this report had evidence of bloodstream infections at the time of admission to military medical facilities, whether the infections were acquired from environmental sources in the field or during treatment at other military medical facilities is unknown,” the Army said.

A. baumannii, which is found in water and soil and resistant to many types of antibiotics, surfaces occasionally in hospitals, often spread among patients in intensive care units.

The infection was also found in soldiers with traumatic injuries to their arms, legs and extremities during the Vietnam War.

Spread of the infection is often halted when health-care workers wash their hands and those of their patients with alcohol swabs, actively monitor those with wounds to the extremities and promptly identify the infected.

Development of better drugs also is needed to help contain future outbreaks of the infection, Army officials said. In some cases, the only effective antibiotic is colistin, an older drug that is rarely prescribed today because of its high toxicity.

Health-care providers in the United States are urged to watch for A. baumannii infections among soldiers who have been recently treated at military hospitals, especially those who were in intensive care units.

SOURCE: Morbidity and Mortality Weekly Report, November 19, 2004.