['To investigate the relationship between ciprofloxacin or imipenem use and antimicrobial resistance in Pseudomonas aeruginosa.', 'A retrospective review of monthly antimicrobial susceptibility reports for ciprofloxacin (1988 to 1995) and imipenem (1987 to 1995) against P aeruginosa and hospital antimicrobial use records at a tertiary care teaching hospital in Winnipeg, Manitoba. Data were entered into a relational database, R:Base 4.5++, collated, transferred to a spreadsheet and subjected to linear regression analysis. The relationship between ciprofloxacin or imipenem use and resistance was assessed using a Pearson correlation.', 'Ciprofloxacin-resistant P aeruginosa increased from 1.0% of all isolates in 1988 to 10.0% in 1995. A significant (P=0.05) correlation was demonstrated between the amount of ciprofloxacin use and prevalence of ciprofloxacin-resistant P aeruginosa (r=0.73, P=0.05). Imipenem-resistant P aeruginosa increased from 1.0% of isolates in 1987 to a maximum of 10.4% in 1991, and subsequently decreased to 5.4% in 1995. Imipenem use and the prevalence of imipenem-resistant P aeruginosa were significantly correlated (r=0.85, P=0.014).'] Do ciprofloxacin or imipenem use correlates with resistance in Pseudomonas aeruginosa?