Emergence of multidrug resistance in bacteria and impact on antibiotic expenditure at a major army medical center caring for soldiers wounded in Iraq and Afghanistan.

Since the invasions of Iraq and Afghanistan, the epidemiologic traits of clinical isolates at Walter Reed Army Medical Center have shifted toward drug-resistant strains of microorganisms, particularly among the gram-negative bacteria. Moreover, antibiotic prescribing patterns during this period have changed remarkably and mirror the emergence of these organisms at our institution.