Clinical and economic impact of multidrug resistance in nosocomial Acinetobacter baumannii bacteremia

OBJECTIVE. To investigate the impact of antimicrobial resistance on clinical and economic outcomes among hospitalized patients with multidrug-resistant (MDR) Acinetobacter baumannii bacteremia. DESIGN. A retrospective, matched-cohort study. SETTING. A tertiary care university teaching hospital METHODS. A matched case-control (1:1) study was conducted to compare the differences in clinical and economic outcomes of patients with MDR A. baumannii bacteremia and patients with non-MDR A. baumannii bacteremia. Case patients were matched to control patients on the basis of sex, age, severity of underlying and acute illness, and length of hospital stay before onset of bacteremia. RESULTS. Forty-six (95.8%) of 48 cases with MDR A. baumannii bacteremia were eligible for the study and matched with appropriate controls. The sepsis-related mortality rate was 34.8% among cases and 13.0% among controls, for an attributable mortality rate of 21.8% (adjusted odds ratio, 4.1 [95% confidence interval, 1.1-15.7]; P = .036). After the onset of bacteremia, cases and controls had a significantly different length of hospital stay (54.2 vs 34.1 days; P = .006), hospitalization cost (US$9,349 vs US$4,865; P = .001), and antibiotic therapy cost (US$2,257 vs US$1,610; P = .014). Thus, bacteremia due to MDR A. baumannii resulted in 13.4 days of additional hospitalization and US$3,758 of additional costs, compared with bacteremia due to non-MDR A. baumannii. CONCLUSIONS. Patients with MDR A. baumannii bacteremia had a higher mortality rate and incurred greater medical costs than patients with non-MDR A. baumannii bacteremia.