IDSA Conference: Iraq bug causing hospital outbreaks linked to soldiers

Iraq bug causing hospital outbreaks linked to soldiers

A. baumanii strain resistant to many drugs

Soldiers who served in Iraq and Afghanistan have acquired a drug-resistant bacteria that is fueling nosocomial outbreaks in military hospitals, an epidemiologist recently reported in San Francisco at the annual meeting of the Infectious Diseases Society of America.

Prior to the Iraq war Acinetobacter baumanii rarely was seen in U.S. military hospitals. Since March 2003, more than 250 patients — mostly soldiers who served in the Middle East — have been identified as infected with the Acinetobacter organism.

"It’s the cause of recent hospital-based outbreaks and it’s very hard to eradicate," said Paul Scott, MD, chief of epidemiology at Walter Reed Army Institution of Research in Washington, DC. "Essentially, it’s being imported into our hospitals."

Potentially vulnerable are elderly, ill, and immunocompromised patients. Infections caused by Acinetobacter have long been a problem in European and Israeli hospitals, but had been rare in U.S. hospitals.

Scott tracked infections in 148 people, most of whom were active-duty soldiers wounded by land mines, mortar fire, or bombs. Five people who died of the infection were nonmilitary elderly and severely ill patients. No military personnel who served in the Middle East have died from the infection. All 148 cases had been treated in one or more of the following health care facilities: Walter Reed Army Medical Center, Washington, DC; Landstuhl Regional Medical Center, Landstuhl, Germany; the U.S. Naval Ship Comfort; or a field hospital in Iraq.

The bacterium led to various illnesses, including infections in wounds, blood, the respiratory tract and the urinary tract. Most of the patients had fever, which typically lasted a week, stayed in the hospital for an average of 39 days, and were prescribed antibiotic therapy for an average of 29 days.

Acinetobacter is commonly found in soil and water and, because the infections occurred mostly in healthy young soldiers who had been wounded, researchers originally believed the victims were exposed to the bacterium when bits of dirt embedded in their wounds. However, Scott’s research suggests Acinetobacter actually is being acquired in the hospital, much like methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). Acinetobacter is not as virulent as MRSA and isn’t known to lead to death in otherwise healthy people.

There also has been a rise in Acinetobacter in nonmilitary settings, including two recent outbreaks in U.S. hospitals. Though the infection was common in the Vietnam War, the pathogen now has become resistant to antibiotics.

"Concern arises when you are down to a minimum number of antibiotics to which Acinetobacter might develop resistance, eventually resulting in no effective agent," said Col. Joel T. Fishbain, MD, co-author of the study and an epidemiologist in the infectious Diseases Service at the Walter Reed Army Medical Center.

In the military outbreak reported at IDSA, only two antibiotics — imipenem and amikacin — were effective against the bacterium more than half of the time. In fewer than 10%, only imipenem was effective. "This is of particular concern, given that the development of newer drugs against these types of organisms has not kept pace with those drugs that are used to treat MRSA and VRE," Fishbain said.