Antibiotic utilization: Is there an effect on antimicrobial resistance?

The antimicrobial resistance problem in hospitals continues to worsen. In particular, extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) and vancomycin-resistant enterococci (VRE) are significant causes of morbidity and mortality among critically ill patients. Treating infections caused by these pathogens presents therapeutic dilemmas. The association between broad-spectrum β-lactam overutilization and selection for ESBL-KP has been appreciated for some time; several institutions have reported a decrease in the prevalence of ESBL-KP with a shift in antibiotic utilization from third-generation cephalosporins to other broad-spectrum drugs. Currently, optimal treatment of ESBL-KP includes the carbapenems, but widespread use of these drugs is expensive and may be associated with further selection of antibiotic resistance and/or superinfection with other inherently resistant pathogens. VRE are especially difficult organisms to treat because of their inherent and acquired resistance to most currently available antibiotics. The prevalence of VRE has also been documented to decrease upon a shift in antibiotic use from third-generation cephalosporins to broad-spectrum antibiotics of other classes. Thus, antibiotic utilization measures appear to contribute to the control of the emergence of multidrug-resistant pathogens such as ESBL-KP and VRE.