# Rapid Typing of Extended‐Spectrum β‐Lactamase (ESBL)‐ and Metallo‐β‐Lactamase (MBL)‐Producing Enterobacterales Using Fourier Transform Infrared (FT‐IR) Spectroscopy

## TL;DR

This study shows that FT-IR spectroscopy can quickly identify similarities in antibiotic-resistant bacteria, which could help in tracking outbreaks.

## Contribution

The study demonstrates the effectiveness of FT-IR spectroscopy as a rapid typing method for ESBL- and MBL-producing Enterobacterales.

## Key findings

- FT-IR spectroscopy showed high concordance with genotyping methods for Klebsiella pneumoniae and Enterobacter cloacae complex isolates.
- The IR Biotyper detected multiple clusters that aligned with PFGE, MLST, and wgSNP results.
- Some discordant results suggest the need for confirmatory genotyping in outbreak investigations.

## Abstract

This study investigated the usefulness of the IR Biotyper, which types bacterial strains using Fourier transform infrared (FT‐IR) spectroscopy, against extended‐spectrum β‐lactamase (ESBL)‐ and metallo‐β‐lactamase (MBL)‐producing Enterobacterales. Sixty‐six clinical isolates (20 ESBL‐producing Klebsiella pneumoniae, 15 IMP‐producing K. pneumoniae, and 31 IMP‐producing Enterobacter cloacae complex isolates) were analyzed using the IR Biotyper, pulsed‐field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole‐genome single‐nucleotide polymorphism (wgSNP) analyses and the results were compared. Of the 20 ESBL‐producing K. pneumoniae strains analyzed, the IR Biotyper detected three clusters. Of these clusters, two were determined as respective clusters by PFGE and wgSNP analyses, and the strains included in each cluster showed the same STs. The IR Biotyper detected three clusters in the analysis of 15 IMP‐producing K. pneumoniae strains. Of these clusters, strains in the two clusters showed high concordance with PFGE, MLST, and wgSNP analyses. The IR Biotyper identified six clusters among the IMP‐producing E. cloacae complex isolates. These results were fully concordant with those of PFGE, MLST, and wgSNP analyses in the two clusters. The range of adjusted Rand index was 0.734–0.967 between the IR Biotyper and PFGE and 0.658–0.857 between the IR Biotyper and MLST or wgSNP analyses. This study demonstrated the performance of IR Biotyper for the detection of clonal similarities in ESBL‐ and IMP‐producing Enterobacterales and it might be useful for outbreak investigation.

Clinical isolates of Klebsiella pneumoniae and Enterobacter cloacae complex were analyzed using FT‐IR spectroscopy and genotyping methods. High concordance was observed, demonstrating the potential of FT‐IR spectroscopy as a rapid screening tool. Some discordant results highlight the need for confirmatory genotyping in outbreak investigations.