A rapid method for detecting and distinguishing metallo-β-lactamase-and serine carbapenemase-producing Enterobacteriales using MALDI-TOF MS

Xiaopeng Jing; Yanyan Hu; Tingting Wu; Xing Zhang; Shaofeng Luo; Wei Wang; Xiaochun Min; Ruiling Sun; Ji Zeng

doi:10.3389/fmicb.2022.1096987

A rapid method for detecting and distinguishing metallo-β-lactamase-and serine carbapenemase-producing Enterobacteriales using MALDI-TOF MS

Front Microbiol. 2023 Jan 13:13:1096987. doi: 10.3389/fmicb.2022.1096987. eCollection 2022.

Authors

Xiaopeng Jing¹, Yanyan Hu², Tingting Wu¹, Xing Zhang¹, Shaofeng Luo¹, Wei Wang¹, Xiaochun Min¹, Ruiling Sun¹, Ji Zeng¹

Affiliations

¹ Department of Clinical Laboratory, Wuhan Fourth Hospital, Wuhan, China.
² Clinical Microbiology Laboratory, School of Medicine, 2nd Affiliated Hospital of Zhejiang University, Zhejiang University, Hangzhou, China.

Abstract

Introduction: Carbapenemase-producing Enterobacteriales (CPE) are a major health threat worldwide, and therefore the development of rapid detection methods is needed. Here, we established a method to distinguish metallo-β-lactamase and serine carbapenemases using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with ethylenediaminetetraacetic acid (EDTA) and phenylboronic acid (PB).

Methods: To assess the specificity and sensitivity of the method, 110 carbapenemase-producing and 72 carbapenemase-negative Enterobacteriales isolates were collected, among which 51 strains produced only metallo-β-lactamase, 55 strains only serine carbapenemases, and four strains both metallo-β-lactamase and serine carbapenemases. In the proposed MALDI-TOF MS method, imipenem (IPM) and the bacterial strains to be tested were mixed, EDTA and/or PB was added, and the mixture was incubated for 4 h. The carbapenemase type was confirmed by the IPM waveform spectrum before and after incubation.

Results: Based on the presence, absence, and recovery of the IPM-cyano-4-hydroxy-cinnamic acid-specific waveform peak near 479 m/z, the detection sensitivity and specificity of the method were 98.2 and 100%, respectively.

Discussion: Although CPE detection by MALDI-TOF MS has been studied previously, our method distinguishes between metallo-β-lactamase and serine carbapenemases, which will be very helpful for the clinical selection of antibiotics.

Keywords: Carbapenemase-producing Enterobacteriaceae; MALDI-TOF MS; Phenylboronic acid; ethylenediaminetetraacetic acid; metallo-β-lactamases; serine carbapenemases.