Assessing the impact of antimicrobial resistance.

Abstract

Trends in infectious disease mortality, contributing factors, and resistance patterns of commonly isolated microorganisms are described. Antimicrobial resistance was first reported in 1941 with sulfonamides. The frequency of antimicrobial resistance has increased in hospital and community settings, resulting in therapeutic failures, the use of increasingly costly and toxic antimicrobials, extended hospital stays, and increased morbidity, mortality, and health care costs. Retrospective analysis of infectious disease mortality in the United States reveals that resistance has increased despite the development of new antimicrobials. Factors contributing to antimicrobial resistance include patients' expectations of receiving an antimicrobial prescription after an office visit (even when one is not warranted), low vaccination rates among the elderly, international travel, and continuous exposure to small amounts of antimicrobials in the food supply. Analysis of susceptibility and resistance patterns of more than 10.3 million isolates found that 36%, 30%, and 31% of Escherichia coli isolates were resistant to ampicillin, ampicillin-sulbactam, and piperacillin, respectively. E. coli and Klebsiella pneumoniae exhibited reduced susceptibility to ceftazidime in certain regions of the country. Pseudomonas aeruginosa exhibited resistance to ciprofloxacin, imipenem, gentamicin, and ceftazidime. The occurrence of ciprofloxacin- and levofloxacin-resistant Staphylococcus aureus was similar, while the frequency of erythromycin-resistant S. aureus varied widely nationwide. Nationwide susceptibility to cefotaxime was significantly lower than that to ceftriaxone. Antimicrobial resistance is an increasing problem that contributes to morbidity, mortality, and increased health care costs. Analysis of susceptibility and resistance patterns of specific microorganisms is necessary to gain further insight into the causes of antimicrobial resistance and ways to reduce it.