BACKGROUND Carbapenem-resistant Enterobacterales (CRE) poses a significant public health threat. In Korea, the current surveillance systems do not distinguish between colonisation and infection. This study evaluated the clinical and socioeconomic burden of CRE infections in Korea.

METHODS This retrospective study was conducted at 15 medical institutions. All patients with CRE-positive clinical specimens in 2022 were classified as either 'CRE-infected' or 'colonised'. Clinical data and medical costs were collected for the 'CRE-infected' cohort. A predictive logistic regression model based on sex, age, presence of bacteraemia, and bacterial species was developed to estimate the nationwide incidence of CRE infections. For cases of CRE bacteraemia, the clinical information of the matched control groups (no-infection, 3rd-generation-cephalosporin [3GC]-susceptible infection, and 3GC-resistant infection) was collected.

FINDINGS Among the 4848 reported CRE cases, 1087 (22.4%) were classified as infections, including 586 bacteraemia cases. The most common infection sites were intra-abdominal (34.0%) and pulmonary (31.3%). Carbapenemase-producing Enterobacterales accounted for 74.2% of cases, with Klebsiella pneumoniae carbapenemase (84.4%) being the most prevalent. The 30-day and 90-day mortality rates were 29.3% and 40.8%, respectively. The predictive model estimated 7117 CRE infections nationwide, including 1897 cases of bacteraemia. The economic burden of CRE infections in 2022 was estimated to be $517,738,296, with excess costs ranging from $108,382,302 to $401,186,712, compared with carbapenem-susceptible infections and cases without infection.

CONCLUSIONS This study highlights the substantial clinical and socioeconomic burden of CRE infections in Korea. Given the continued increase in reported CRE cases even after 2022, urgent measures are required to address this growing public health challenge.