Acinetobacter and Wound Infections

Infection is a complication of battlefield injuries that can lead to significant morbidity and mortality. During the Vietnam War conflict, a 4% incidence of wound infection was reported despite 80% of wounds undergoing debridement/irrigation and 70% receiving antibiotics. Although the incidence of wound infection has not been determined for Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF), it is unclear if it is higher than the 4% incidence noted during the Vietnam conflict.

First noted in April 2003, nosocomial, multidrug-resistant Acinetobacter baumannii infections have spread along the evacuation chain from medical facilities in Iraq, through hospitals in Europe, to the United States. After the onset of ground operations in Iraq, A baumannii-calcoaceticus complex (ABC) was recognized as an important bacterial pathogen infecting the wounds of casualties. The initial report described 102 patients with ABC recovered from their blood cultures; 83% of these patients were from OIF/OEF. These numbers were in excess of historical norms.

Among patients admitted to Brooke Army Medical Center (San Antonio, Texas) from Iraq and Afghanistan, there were approximately 10 wound infections for every one patient with ABC bacteremia. Infections frequently involve burn casualties, as well as bone and soft-tissue infections. Although ABC is often considered a low virulent pathogen, its ability to develop broad-spectrum antimicrobial resistance to all modern antibiotics can lead to poor outcomes, especially in immunosuppressed patients. ABC is also of concern because it is often associated with nosocomial transmission of infection. Although the etiology of ABC has not been clearly elucidated, there is supporting evidence that nosocomial transmission was leading to the spread of the infection.

Although ABC’s role as a pathogen was being determined among casualties of OIF/OEF, more virulent pathogens that had classically been associated with battlefield trauma — such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus — were also being seen. These pathogens are notable for their more destructive properties and greater propensity to result in poor outcomes. Even more troubling, however, is the multidrug-resistant patterns of these pathogens, including methicillin-resistant S aureus (MRSA), extended-spectrum b-lactamase-producing K pneumoniae, and multidrug-resistant P aeruginosa

— Clinton K. Murray, MD, MAJ, MC, US Army