Multi-hospital analysis of antimicrobial usage and resistance trends.

We report a pilot study comparing antimicrobial usage and antimicrobial resistance trends for prominent nosocomial pathogens between 1994-1996. A convenience sample of ten hospitals participated in this retrospective review. We found a large variation in antimicrobial use and resistance trends and that many hospitals did not have data readily available to evaluate drug usage and resistance rates. A significant strong positive correlation was observed between the usage of ceftazidime and the prevalence of ceftazidime resistant Pseudomonas aeruginosa (r = 0.8, p = 0.005) and of ceftazidime resistant Enterobacter species (r = 0.8, p = 0.02). The presence of antibiotic control policies correlated with lower rates of some resistant strains and less antibiotic use. Our findings can be a useful starting point for hospitals that want to systematically measure antimicrobial use and resistance. Hospital laboratories, pharmacies, and infection control departments must work together to develop databases that will facilitate such measurements.