Correlation between antimicrobial resistance in Escherichia coli infections in hospitalized patients and rates of inpatient prescriptions for selected antimicrobial agents, Department of Defense hospitals, 2010-2014.

During the past decade, increasing prevalence of antimicrobial resistance in Escherichia coli has complicated treatment of infections. Several studies have shown significant correlations between levels of susceptibility and levels of prescription use for preferred antimicrobials; however, most of these studies were conducted outside the U.S. and are outdated. This analysis aimed to identify inpatient E. coli infection trends and correlations between prescriptions and antimicrobial resistance observed among hospitalized Department of Defense beneficiaries during 2010-2014. A descending trend was observed for E. coli infection incidence during 2010-2013, with an upward trend noted for the last year of the study. Despite quarterly fluctuations, descending trends were noted among prescription rates and stable trends were observed for resistance rates throughout the study period. A statistically significant moderate and positive correlation (r=0.53; p=0.01) was noted between levels of ciprofloxacin prescriptions and ciprofloxacin resistance for E. coli isolates. Stewardship programs are encouraged to monitor this relationship.