COLUMBIA, Mo. - Improvised explosive devices (IEDs) are often to blame when soldiers are wounded in Iraq and Afghanistan. The makeshift weapons account for a high percentage of musculoskeletal injuries that, in both theaters, frequently lead to difficult-to-treat infections. Military physicians have faced challenges treating such infections, and the U.S. Army has turned to a University of Missouri-Columbia research physician to study the problem and develop medical solutions.
"The bacteria we¡¦re seeing is quite different than what we¡¦re used to dealing with," said Jason Calhoun, J. Vernon Luck Distinguished Professor and chair of the MU School of Medicine¡¦s Department of Orthopaedic Surgery. "Many are resistant to common types of antibiotics."
Calhoun has been awarded a $1.6 million grant from the U.S. Army Institute of Surgical Research to study infections that are multi-drug resistant. He is partnering with Walter Reed Army Medical Center and Brooke Army Medical Center to build a database on veterans with infections and study how those infections could be better treated.
In Iraq and Afghanistan, Calhoun said about 70 percent of all injuries involve extremities. That statistic is higher than in past conflicts due to significant advances in protective body armor, he said. In addition, about half of those with extremity injuries develop significant infections that require additional treatment and surgery, which often leads to amputation, Calhoun said.
During a four-year period, lab tests will be conducted at MU¡¦s medical school to simulate blast wounds and examine four types of infections that have become increasingly common among those injured in action. The bacteria being studied include: Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus.
- identify antibiotics that can effectively treat those bacteria;
- determine when antibiotics should be administered after an injury; and
- determine an effective duration of antibiotic treatment to reduce the growth of resistant strains.
The study will give the Army guidance on how field medics can better administer antibiotics to injured troops. Calhoun said some of the infections occur naturally because of bacteria common to the region, such as soil contamination following the injury. Others result from intentional acts by opposing forces ¡V devices which purposely contain harmful agents like manure and chemicals, he said.
"Every war is different, but this one is different because of the amount of explosive devices that our soldiers are encountering," Calhoun said. "In the last few months, there has been an increase in the tonnage of those devices, and the blast injuries are even worse. Over the past three years, many of our soldiers have had open fractures where the soft tissue is injured and the bone is injured, and there is significant contamination of that tissue. Many of those soldiers go on to develop a severe infection of their extremity. Ultimately this research could mean fewer extremity infections, fewer surgeries and fewer amputations."
He also is optimistic the advances can benefit the U.S. civilian population and lead to improved treatments for injuries occurring in automobile and farm accidents.
Calhoun has led the American Association of Orthopaedic Surgeons (AAOS) infections committee. Last year, he co-chaired an AAOS symposium on the subject of war wounds and co-edited a special AAOS journal issue dedicated to war-wound research.