OBJECTIVES: Despite the importance of infections caused by antibiotic-resistant bacteria, which can pose a major threat to medical care, the results of related studies are scarce. We aimed to estimate the clinical and economic burden of patients with antibiotic-resistant bacteremia due to ESBL-producing or carbapenem-resistant K. pneumoniae and E. coli.

METHODS: The data was collected from 10 tertiary hospitals in the Republic of Korea over 11-months period between April, 2021 to March, 2022. We conducted a retrospective cohort study on patients with ESBL-producing or CRE(K. pneumoniae or E. coli) bacteremia and matched controls with susceptible infection group and without infection(control) group. Patients were equally classified into the Resistant, Susceptible, and Control(N)-groups. We estimated clinical and economic burden by comparing the length of stay, mortality, and total medical cost.

RESULTS: After PS matching, mean Length of Stay was longest for the R-group (32.6 days) followed by N-group (23.0 days) and S-group (15.3 days). The 7-day mortality rates for R, S, and N groups were 4.2%, 3.9% and 1.9%, respectively. The 30-day mortality rates were significantly higher in the R-group than in the S group (11.7% vs. 5.0%, p = 0.017). The total cost was highest in the R-group, and lowest in the N-group. Compared to S-group, the R group had KRW 6,527,940 more and compared to N-group, the R-group had KRW 9,506,700 more.

CONCLUSIONS: Patients with antibiotic-resistant bacteria showed higher mortality and more medical expenses compared to the antibiotic-susceptible bacteremia and no-infection. In consideration of the high clinical and economic burden of patients with ESBL-producing and CRE bacteremia, appropriate infection control measures should be prepared to prevent the spread of antibiotic-resistant bacteria and policies to reduce the disease burden of patients with ESBL-producing and CRE bacteremia.