Back in June, there was an unnerving report from the Centers for Disease Control and Prevention that NDM-1, the “Indian supergene” that renders common hospital-acquired infections practically untreatable, had been found in the military hospital at Bagram Air Base in Afghanistan. The gene was being carried by a gut bacterium, Providencia stuartii, that was causing septicemia in an Afghan national who had been taken in by the military hospital. The particular strain of NDM-1 could be treated only by a single drug, aztreonam; it was resistant to everything else. Unsurprisingly, the victim died.

Though it wasn’t explicitly stated, the subtext of the CDC’s brief bulletin was clear: By extending compassion to the local resident (who was badly burned and had been treated at a hospital in Kabul), the military staff had brought into their hospital a highly resistant organism that could endanger their troops. It made me wonder, at the time, how often this happened, and what the consequences might be.

A study performed at Bagram, and published this month in Infection Control and Hospital Epidemiology, supplies an answer, and it’s a troubling one.

A team of Air Force physicians and researchers analyzed every positive bacterial culture performed at the Bagram hospital over a 12-month period, from September 2007 to August 2008. (Note: This is before the first report of NDM-1.) That is a small hospital — 26 inpatient beds and 17 intensive-care beds — but over that year, it had high traffic: 765 US personnel, and an additional 1,071 Afghans. The paper notes: “Care of host-nation troops and noncombatants injured by combat operations is a high priority in deployed US military medical facilities. Care is also provided to other civilians, many of whom are children, as space and resources permit.”

Out of all those patients, there were 266 patients whose injections yielded 411 bacterial isolates. Just over half of the isolates, 211, were multi-drug resistant, that is, resistant to at least three classes of antibiotics.

Here is the troubling part: In both raw numbers and percentages, Afghan nationals being cared for in the Bagram hospital accounted for a far larger amount of highly resistant bacteria than US forces did. Nineteen percent of the 73 bacterial isolates recovered from US forces were multi-drug resistant; 60 percent of the 319 bacterial isolates recovered from Afghan nationals were.

Cutting the data another way, 241 of the bacterial isolates from Afghan patients were the Gram-negatives — E. coli, Acinetobacter and Klebsiella — that cause common and formidable hospital-acquired infections; 168, or 70 percent, of those were multi-drug resistant, and 58, or 24 percent, were ESBL (extended-spectrum beta-lactamase) producers, meaning they could only be treated by one remaining class of drugs. (In contrast, of the 14 US forces who had multi-drug resistant infections, 10 had MRSA, and four had Gram-negative infections, three of which were ESBL.) Of note, 58 percent of the resistant bacteria recovered from the Afghan patients was found within 48 hours of their admission to the hospital, meaning that they acquired the infection on the outside, before they were admitted.

In addition to surveying patients, the researchers checked surfaces and equipment in the hospital for contamination with resistant bacteria. Out of 100 cultures, they found 18 multi-drug resistant Gram-negatives, including three in an operating room.

It is worth thinking about what comes through this hospital. The paper says: “traumatic injuries, including blast injuries (which includes injuries from improvised explosive devices), gunshot wounds, motor vehicle accidents, other types of trauma, and burns; and nontrauma diagnoses, including skin and soft tissue infection, urinary tract infection, and other medical conditions (primarily pneumonia and sepsis).” In other words, profoundly traumatic, messy, contaminated wounds — perfect breeding grounds for hospital-acquired infections.

The authors are clearly troubled by the possibility that the hearts-and-minds mission to extend US-level care to local people may inadvertently be putting US troops in danger, by inviting a potential infection source into the hospital. That risk is amplified by the fact that many of the Afghan patients are likely to stay in the hospital longer than the US ones do. They acknowledge that they have little defense against the possibility of infection spreading, expect for becoming and staying excellent at infection-control procedures. But even health-care workers in highly equipped, well-staffed US hospitals struggle to be excellent at those tasks; imagine how much more difficult that must be in a war zone.

They say:

Transfer of Afghan patients to non-US facilities is often delayed because of limited local health care infrastructure. Inpatient stays for seriously ill or injured patients can extend for weeks or months at these deployed hospitals, increasing the risk of cross-contamination among patients, including injured US personnel, who typically are admitted for only 12–72 hours…

Stabilization of US troops for rapid evacuation back to the United States and providing care for local nationals with complex and sometimes long-term needs are 2 distinctly different missions. Mixing the care of these, especially in a setting in which the local populace has a high baseline rate of MDR-GNR incidence, makes the practice of good infection control essential… Continued study of the epidemiology of MDR bacteria in deployed hospitals is essential to controlling these emerging pathogens and protecting our wounded personnel.

Cite: Sutter DE et al. High Incidence of Multidrug-Resistant Gram-Negative Bacteria Recovered from Afghan Patients at a Deployed US Military Hospital. Infection Control and Hospital Epidemiology, 2011;32(9):854-860. DOI: 10.1086/661284

See Also:

Acinetobacter: PHIL, CDC