Prior antimicrobial exposure and the risk for bloodstream infection with fluconazole-non-susceptible Candida strains.

Candida species are a common cause of bloodstream infection among hospitalized patients. Increasingly these infections are caused by strains resistant to commonly used antifungal agents. The aim of this study was to assess the association between exposure to specific antimicrobial agents and subsequent bloodstream infection with fluconazole-non-susceptible and fluconazole-susceptible Candida strains. A retrospective case-case-control study was performed. From 2002 to 2006, 50 consecutive patients with hospital-acquired bloodstream infection caused by Candida strains not fully susceptible to fluconazole were identified (case group 1). For comparison, 54 patients with fluconazole-susceptible candidaemia (case group 2) and a control group of 104 patients without candidaemia were studied. Models were adjusted for demographic and clinical risk factors. The risk for candidaemia associated with exposure to specific antimicrobial agents was assessed. Piperacillin/tazobactam (odds ratio (OR) 6.8, 95% confidence interval (CI) 1.4-32.2) and ciprofloxacin (OR 8.0, 95% CI 1.5-42.5), but not fluconazole, were significant risk factors for bloodstream infection with fluconazole-non-susceptible Candida. Only ciprofloxacin (OR 7.8, 95% CI 1.2-50.7) was associated with bloodstream infection with fluconazole-susceptible Candida. Despite adjustment for prior exposure to fluconazole, exposure to specific antibacterial agents was associated with hospital-acquired bloodstream infection with fluconazole-non-susceptible Candida.