Divergent epidemic trajectories of ESBL-producing and carbapenemase-producing Enterobacterales in French hospitals: a nationwide modelling study.

OBJECTIVES

Carbapenemase-producing Enterobacterales (CPE) have emerged as a major public health concern despite remaining less frequent than extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E). Conventional surveillance primarily reports annual incidence but provides limited information on epidemic velocity. We compared the epidemic trajectories of ESBL-E and CPE in French hospitals using nationwide surveillance data.

METHODS

We conducted a nationwide retrospective modelling study using data from the French SPARES surveillance programme (2019-2024). Annual incidence densities (cases per 1,000 patient-days) were analysed using comparative log-linear regression to estimate annual percent change (APC), doubling time and the projected year at which CPE incidence would reach the observed 2024 ESBL-E incidence under unchanged epidemic dynamics. Species distribution and carbapenemase families were also described.

RESULTS

Between 2019 and 2024, ESBL-E incidence remained substantially higher than CPE incidence (0.53-0.70 vs 0.010-0.037 cases per 1,000 patient-days). ESBL-E incidence remained stable over time (APC, 3.1%; P for temporal trend = 0.29), whereas CPE incidence increased significantly faster (APC, 32.8%; P for interaction <0.001), corresponding to estimated doubling times of 23.0 and 2.4 years, respectively. Assuming continuation of current epidemic dynamics, projected CPE incidence would reach the observed 2024 ESBL-E incidence around 2033 (95% CI, 2031-2036). Species distribution differed significantly between ESBL-E and CPE (P<0.001), with Escherichia coli predominating among ESBL-E and Klebsiella pneumoniae among CPE.

CONCLUSIONS

Although CPE incidence remains markedly lower than ESBL-E incidence, its epidemic trajectory is substantially steeper. Comparative modelling of epidemic trajectories complements conventional surveillance and may help anticipate future antimicrobial resistance burden while opportunities for infection prevention and antimicrobial stewardship remain.