Comparison of clinical outcomes of patients infected with KPC- and NDM-producing Enterobacterales: a retrospective cohort study

Objectives: We aimed to compare clinical outcomes of patients with Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales and those with New Delhi metallo-β-lactamase (NDM)-producing Enterobacterales.

Methods: We performed a retrospective cohort study of all adult patients with KPC- or NDM-producing Enterobacterales isolates in a 2700-bed tertiary referral hospital in Seoul, South Korea, between 2010 and 2019. The primary outcome was 30-day mortality after first isolation of KPC- or NDM-producing Enterobacterales. The secondary outcome was the development of infection within 30 days by the colonizing isolates, among colonized patients. We performed Cox regression analysis for 30-day mortality and competing risk analysis for development of infection.

Results: A total of 859 patients were identified during the study period; 475 (55%) had KPC and 384 (45%) had NDM. Thirty-day mortality was significantly higher in the KPC group than in the NDM group (17% (81/475) vs 9% (33/384); p < 0.001). The KPC group developed infection within 30 days from the initial colonization after first isolation more frequently than the NDM group (8% (27/353) vs. 3% (10/295); p 0.02). Multivariable analysis revealed that independent risk factors for 30-day mortality were solid cancer (adjusted hazard ratio (aHR) 2.51; 95% confidence interval (CI) 1.66-3.79; p < 0.001), solid organ transplant (aHR 0.32; 95% CI 0.17-0.61; p < 0.001), a high APACHE II score (aHR 1.11; 95% CI 1.08-1.13; p < 0.001), KPC-producing Enterobacterales (aHR 1.69; 95% CI 1.02-2.79; p 0.04), previous carbapenem use within 3 months (aHR 1.86; 95% CI 1.26-2.75; p < 0.001) and site of KPC- or NDM-producing Enterobacterales infection at the time of the first culture (p < 0.001).

Discussion: Our study suggests that KPC-producing Enterobacterales is significantly associated with poorer outcomes than NDM-producing Enterobacterales.