I’ve previously mentioned a bacterial pathogen called Acinetobacter baumannii (a bit more information here), and Mike has discussed it rather frequently. A. baumannii is ordinarilly a commensal bacterium–one that may live on the skin of healthy people for many years without ever causing disease. It becomes a problem when one is immunocompromised in some manner, and unable to keep growth of the bacterium in check. Once this happens, it’s difficult to reverse, as the bacterium brings new meaning to the term “antibiotic resistant.” As Mike blogged previously, a genomic analysis revealed that the bacterium has 52 resistance genes–it’s no wonder it shrugs off everything doctors throw at it. And now, it seems that we’re importing additonal cases of A. baumannii infections from Iraq, which are entering the country as soldiers are transported from hospital to hospital along the evacuation chain. More below the fold.
First, it should be noted that Acinetobacter itself isn’t exactly new:
Forerunners of the bug causing the military infections have been making deadly incursions into civilian hospitals for more than a decade. In the early 1990s, 1,400 people were infected or colonized at a single facility in Spain. A few years later, particularly virulent strains of the bacteria spread through three Israeli hospitals, killing half of the infected patients. Death by acinetobacter can take many forms: catastrophic fevers, pneumonia, meningitis, infections of the spine, and sepsis of the blood. Patients who survive face longer hospital stays, more surgery, and severe complications.
What’s novel is the frequency with which this bacterium is infecting (and killing) soldiers and civilians in Iraq (due largely to the evolution of resistance to multiple antibiotics), and the sheer magnitude of its presence in medical facilities there:
The investigators did find acinetobacter in Iraq. It wasn’t in the dirt – except for a few bugs under a dripping air conditioner outside a health care facility in Mosul – or in the fresh wounds, either. But multidrug – resistant Acinetobacter baumannii was thriving in the emergency rooms, ICUs, and operating rooms of the combat support hospitals. As Paul Scott, one of the lead investigators, told a meeting of civilian epidemiologists in Chicago last spring, “This appeared to be a hospital-associated outbreak throughout our entire health care system.”
The wounded soldiers were not smuggling bacteria from the desert into military hospitals after all. Instead, they were picking it up there. The evacuation chain itself had become the primary source of infection. By creating the most heroic and efficient means of saving lives in the history of warfare, the Pentagon had accidentally invented a machine for accelerating bacterial evolution and was airlifting the pathogens halfway around the world. (Emphasis mine)
There is a bit of a bright side here. The absence of the bacterium in the soil means it doesn’t appear to have a natural environmental reservoir there. Therefore, if the hospital contamination can be cleaned up and contained (a very difficult task even in a well-equipped hospital, admittedly, and even more difficult in a temporary combat support hospital that’s short on even basic supplies), transmission could be minimzed or eliminated.
However, that doesn’t mean that we’ll see the last of drug-resistant A. baumannii. The bacterium has also spread in several hospitals in the United States, as noted in the article, and was the cause of a rather large outbreak (236 cases over 2 months’ time) in Arizona as well. And as the author of the Wired story, Steve Silberman, emphasizes, it’s not over:
Acinetobacter is now a difficult part of daily life in many military hospitals, as it is in civilian ICUs and burn wards worldwide. And the rise of many other types of multidrug-resistant bacteria will make things even more difficult in the next few years, because there are few new antibiotics coming down the pipeline.
“The bugs are outpacing us, and these drugs are not the kind that bring in incredible profits,” says Robert Guidos, director of public policy for the Infectious Diseases Society of America. “We’re planning for bioterrorism and pandemic influenza, but what about the hundreds of thousands of people dying each year from nontheoretical situations? We need to think in longer terms.”
One of the most unsettling long-term questions about the military outbreak is how far the bugs of war will proliferate now that thousands of Iraq veterans have entered the VA hospital system. Many of the older vets who are already there – struggling with chronic conditions for decades, in and out of nursing homes – fall into the bacteria’s target demographic.
We’ve watched MRSA (methicillin-resistant Staphylococcus aureus) go from being a nosocomial (hospital-based) worry to becoming a real problem in the community. We can’t say that Acinetobacter would follow the same path. However, we already know that it’s good at co-opting genes from other bacteria (many of its resistance genes came from Pseudomonas, Salmonella, and E. coli), and these resistant strains don’t appear to have a genetic disadvantage compared to susceptible strains (from anything I’ve read, at least). So if it does jump in the community, I’d guess that we’re in trouble.
For more information: