ABSTRACT

Over the past two decades, rates of antimicrobial resistance have

increased rapidly. Of the two million annual nosocomial infections in

the United States, more than 50% are caused by drug-resistant strains

of bacteria (1,2). Drug resistance has a considerable impact on patient

morbidity and mortality, and is a major economic burden for society with

yearly expenditures ranging from US$4 billion to US$30 billion (1-3).