Military doctors are fighting to contain an outbreak of a potentially deadly drug-resistant bacteria that apparently originated in the Iraqi soil. So far at least 280 people, mostly soldiers returning from the battlefield, have been infected, a number of whom contracted the illness while in U.S. military hospitals.
Most of the victims are relatively young troops who were injured by the land mines, mortars and suicide bombs that have permeated the Iraq conflict. No active-duty soldiers have died from the infections, but five extremely sick patients who were in the same hospitals as the injured soldiers have died after being infected with the bacteria, Acinetobacter baumannii.
"This is a very large outbreak," says Arjun Srinivasan, a lieutenant commander in the U.S. public health service and a medical epidemiologist at the Centers for Disease Control.
Acinetobacter was the second most prevalent infection for soldiers in Vietnam, but the military did not expect to see it as part of Operation Iraqi Freedom. Researchers are still working to understand where it came from and how patients were infected.
Doctors worry not only about soldiers who are already infected but also those who are carrying Acinetobacter on their skin even though they themselves are not infected. Lt. Cmdr. Kyle Petersen, an infectious disease specialist at National Naval Medical Center (NNMC) in Bethesda, Md.,says his hospital treated 396 patients who had been wounded in Iraq between May 2003 and February 2005. About 10% were infected and another 20% were found to have Acinetobacter bacteria on their skin but were not infected. The rate of appearance of the bacteria has "been flat-out steady," says Petersen.
The same has been true at Army hospitals that include Walter Reed Medical Center in Washington, D.C., Tripler Medical Center inHawaii and Brooke Army Medical Center in San Antonio, where there has been a total of about 240 cases of patients infected, while another 500 have carried the bacteria, according to Col. Bruno Petrucelli, director of epidemiology and disease surveillance for the U.S. Army Center for Health Promotion and Preventive Medicine.
Petrucelli says the five patients who died were at Army hospitals — most of them at Walter Reed. They were already suffering from serious health problems before they contracted the bacteria. "These were the sickest of the sick," says Petrucelli. The infections are split evenly among wound infections, respiratory infections and a mix of bloodstream and other infections.
Preventing the bacteria's spread has required doctors to take extreme care, putting all patients who are returning from the theater of war into isolation. "It's one of those pathogens that once it gets into a population and a chain of care, it can set up shop. Trying to contain the spread of this infection to other people is very difficult," says Andrew Shorr, a doctor who recently left Walter Reed for Washington Hospital Center. "What has happened over the past 18 months is every patient who shows up, we assume they're positive until they are demonstrated negative."
One of those infected in Iraq was Marine Cpl. Sean Locker. On July 10, he was attacked by a suicide bomber in a car while guarding a convoy. Shrapnel hit him in his nose, his right index finger and his right eye, blinding him. His left lung collapsed. But the worst damage was done to his left arm. It was amputated, and Locker says he knew it would be as soon as he looked down at it. "I tried to stay level-headed," he says.
Locker, 25, was flown to an army base in Landstuhl, Germany, and then to NNMC in Bethesda. There, doctors found that what was left of his arm after the amputation had been infected with Acinetobacter. For Locker, the prognosis was good, as two years of hard experience treating patients who had returned from war had taught doctors how to deal with the infection — and to prevent it from spreading to sicker patients. Using imipenem, one of three intravenous antibiotics effective against Acinetobacter, doctors are treating Locker's infection. He hopes to go home soon and buy a new truck.
But other patients have been less fortunate, as they have suffered from infections of the bone, the bloodstream or of internal organs, which have complicated their care. Lt. Cmdr. Petersen says that NNMC's annual bill for the kind of antibiotics Locker received has increased tenfold to $200,000.
Besides imipenem, which carries a risk of seizure, two other drugs have worked. Another is amikacin, which does not work for bone infections and has not been effective against some strains of the bacteria. A third is colistin, an antibiotic doctors had stopped using because of its toxic effects on the kidneys.
"It is a scary thing about any drug-resistant bacteria, when you grow it for the very first time out of a patient and you've only got three antibiotics, one so old that we had to bring it back from the archives," says Col. Joel Fishbain, chairman of the infection-control committee at Walter Reed.
The methods used by the military in dealing with Acinetobacter represent a model for preventing drug-resistant infections, which kill some 100,000 patients per year in the U.S.
Patients arriving are swabbed in the armpit and the groin. Until the cultures show they are negative, the soldiers are kept in isolation. Doctors and nurses make sure to wear gloves and gowns when coming into contact with them. At NNMC, the cost of gowns and gloves to help prevent infection has jumped 80% to $12,000, according to Petersen. Soldiers and their family members are not confined to the room, however — the main point is to keep doctors and nurses from spreading bacteria from one patient to another.
At NNMC, an added step has been taken by making sure infected and contaminated patients are kept in clusters of rooms separate from those who don't test positive for Acinetobacter.
A patient such as Locker might not even think much about Acinetobacter if the infection can be treated quickly and doesn't cause other problems. But some others feel they weren't given enough information about the bug — perhaps because military researchers themselves were still putting together answers.
Merlin Clark, a civilian contractor who was in Iraq doing humanitarian de-mining, was also infected with Acinetobacter and treated at Walter Reed, according to his wife, Marcie Hascall Clark. "My biggest problem," she says, "isn't so much that my husband had it, but why didn't they tell me about it?"