Winning the Battle

While DoD was accused of being slow to respond, the problem with Acinetobacter was “a moving target” at the beginning, Hospenthal said. Not only was there no standardized testing for that and other resistant bacteria, there wasn’t even an ICD-9 code. That, plus the bureaucracy, made tracking lab results extremely difficult. On top of that, he said he was getting “1,000 press questions asking, ‘How many people had been infected.’ Those were impossible questions.”

Over time, many of the problems were solved, and military medicine began to win the battle.

One obvious advantage is that U.S. troops are no longer being wounded in Iraq, where the problems with Acinetobacter were most serious. Long before the stand-down, however, “I like to think the focus on infection control helped control much of the problem,” Hospenthal said.

Key to that was arming physicians with more epidemiological information so that the initial antibiotics they administered were narrow, instead of broad-spectrum, leading to less antimicrobial resistance. In addition, the presence of infection-control officers was increased, infection-control procedures were monitored more closely, and more-effective isolation of patients was employed.

A standardized program of testing patients for multiple-drug-resistant bacteria was put in place in 2008. “If [patients] are colonized, we put them in contact isolation,” Hospenthal said. He noted that, while nosocomial pneumonia is a serious problem with pathogens such as Acinetobacter, skin, soft tissue and bone infections are more prevalent as wounded troops return to U.S. treatment facilities.

Infections in those sites are especially hard to identify, however. “The guidelines say, ‘Don’t culture wounds unless you think they are infected.’ No wound is completely pure, innocent and without bacteria. You’re really just keeping bacterial counts down for long enough for the patient to recover,” he added. 

In August, an update to the “Guidelines for the Prevention of Infections Associated With Combat-Related Injuries” was published in the Journal of Trauma, with Hospenthal as lead author. Among the most-important recommendations for burns and open wounds are the use of high-dose cefazolin with or without metronidazole for most post-injury indications, directions on when to re-dose antimicrobial agents, how to best employ negative pressure wound therapy and indications for oxygen supplementation in flight.

The update continues to emphasize fundamentals in preventing wound infections, including “post-injury antimicrobials, early wound cleansing (irrigation) and surgical debridement, delayed closure and bony stabilization, with emphasis on maintenance of infection-control measures.”  While the guideline updates address the optimal time to close a wound, military infection-control specialists are looking for better guidance on that topic, including capitalizing on growing knowledge about microbiomes.

Despite the strides being made with prevention, serious treatment issues persist.

In announcing the availability of a new online tool showing regions of the country where antibiotic resistance is especially severe, the Robert Wood Johnson Foundation pointed out last year that U.S. hospitals have seen rapid growth in resistance to the use of carbapenems to treat the Acinetobacter baumannii bacteria, with resistance increasing from less than 5% in 2000 to nearly 40% in 2009, an eightfold increase.

The world is running out of effective antibiotics, Hospenthal added, pointing out, “There is not big money to be made developing new antibiotics for hospitals to keep on restriction for last-ditch treatment.” He noted that drugs for chronic illnesses tend to have better financial profiles for pharmaceutical companies than those for acute conditions.

Furthermore, although Acinetobacter appears to be on the decline in wounded troops, other pathogens are waiting in the wings.

“Infections are often associated with multidrug-resistant bacteria, including gram-negative rods and methicillin-resistant Staphylococcus aureus,” says the introduction to the guideline updates. “We have noted a shift in predominant pathogens from MDR Acinetobacter baummannii-calcoaceticus complex to increasing numbers of extended-spectrum β-lactamase-producing bacteria such as Escherichia coli and Klebsiella pneumoniae and MDR Pseudomonas aeruginosa. These isolates are typically acquired from the healthcare system and mandate increased diligence on appropriate infection-control practices in and out of the combat zone.”

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