Detection of carbapenemases in Enterobacterales susceptible in vitro to meropenem

Abstract

Introduction

Carbapenemase-producing Enterobacterales (CPE) is a global threat. We evaluate the prevalence of CPE among isolates categorized as meropenem-susceptible, but that meet the European Committee on Antimicrobial Susceptibility Testing (EUCAST) screening cut-off values for carbapenemase detection, and analyze the susceptibility of these isolates to new available drugs.

Methods

We analyzed 257 isolates from patients hospitalized in a tertiary hospital in Brazil, from July 2022 to April 2023. Only isolates that met the screening cut-off values established by EUCAST for detection of carbapenemases were analyzed (i.e. meropenem inhibition zones of 25–27 mm by disk diffusion). The detection of carbapenemases was performed by immnunochromatographic testing and confirmed by high-resolution melting-PCR (HRM-qPCR).

Results

We identified 12 (4.7%) CPE including 7 KPC, 4 NDM, and 1 OXA-48-like. The isolates were susceptible to ceftazidime–avibactam (72.7%), meropenem–vaborbactam (100%), imipenem–relebactam (63.6%) and ceftolozane–tazobactam (36.4%).

Conclusion

We highlight the importance of tracking carbapenemases for epidemiological control and therapeutic guidance.