Effect of elevated imipenem/cilastatin minimum inhibitory concentrations on patient outcomes in Gram-negative bloodstream infections

• Published in: Journal of global antimicrobial resistance. 2018-06, Vol.13, p.261-263
• Main Authors: McLaughlin, Milena M., Miglis, Cristina, Skoglund, Erik, Wagner, Jamie, Advincula, Maria R., Scheetz, Marc H.
• Format: Article
• Language: English
• Subjects: Bloodstream infection; Carbapenem; Gram-negative; MIC; Minimum inhibitory concentration; Mortality
• ISSN: 2213-7165; 2213-7173
• DOI: 10.1016/j.jgar.2018.02.003

•Patients receiving directed therapy were less likely to die, despite elevated carbapenem MICs.•No relationship shown between receipt of carbapenem and mortality in patients with carbapenem-resistant Gram-negative BSI.•Cefepime or piperacillin/tazobactam first directed therapy was associated with survival. Carbapenem minimum inhibitory concentration (MICs) are known to predict outcomes for patients with Gram-negative bacteraemia. However, limited data exist on how MICs influence such outcomes when organisms are classified as carbapenem-resistant. The purpose of this study was to evaluate the effect of increasing imipenem/cilastatin MICs on mortality in patients with Gram-negative bloodstream infection (BSI). Patients with an imipenem/cilastatin-resistant (MIC>4mg/L) monomicrobial Gram-negative BSI were eligible for inclusion in the study and were assessed for baseline characteristics, organ function, microbiological data, timing and type of therapeutic treatment, and in-hospital mortality. A total of 62 patients with imipenem/cilastatin-resistant bacterial isolates (MIC>4mg/L) were retrospectively studied. Time to event analyses found no difference between patients who received carbapenem therapy and those who did not (P=0.10). After adjustment, patients receiving directed therapy were less likely to die (adjusted hazard ratio=0.35, 95% confidence interval 0.15–0.83; P