Whole-genome analysis of extensively drug-resistant Enterobacter hormaechei isolated from two hospitalized patients in the United States: A case series of a rare but rising threat

Document Type

Article

Publication Date

12-1-2025

Publication Title

JAC Antimicrob Resist

Abstract

BACKGROUND: New Delhi metallo-beta-lactamases (NDM) confer extensive antibiotic resistance, complicating treatment and leading to poor outcomes. In 2022, two patients at a US academic medical centre in Southeast Michigan were infected with NDM-producing Enterobacter hormaechei.

OBJECTIVE: This study describes two NDM-producing E. hormaechei isolates, recovered in 2022 from hospitalized patients at a large academic medical centre in Southeast Michigan.

METHODS: Identification of E. hormaechei and antibiotic susceptibility patterns were determined using MALDI-TOF mass spectrometry and Vitek2(®) (bioMérieux), respectively, in our clinical microbiology laboratory. Carbapenemase gene detection was performed using Cepheid GeneXpert(®) (Sunnyvale). Sequencing libraries were created using QIAseq FX DNA Library Kit (Qiagen Sciences Inc.) and sequencing was performed on Illumina NextSeq 2000, respectively. EPISEQ(®) CS v1.2.0 and 1928 platforms were used for sequencing analysis.

RESULTS: Two extensively drug-resistant E. hormaechei isolates were recovered from non-urine, non-respiratory sources. Both harboured 25 antimicrobial resistance genes (ARGs), including 13 unique ARGs. Resistance was observed to aminoglycosides [e.g. ant(3')-Ia, aadA2], beta-lactams (bla (ACT-17), bla (ACT-73)), broad-spectrum beta-lactams (bla (NDM-5)), sulphonamides (sul1, sul2), fosfomycin (fosA), glycopeptides (ble) and chlorhexidine (qacE). Isolate 1 carried more ARGs than Isolate 2. Sequence types (ST) for Isolates 1 and 2 were ST93 and ST177, respectively, with ∼88% SNP similarity, indicating non-clonality.

CONCLUSIONS: These findings highlight the clinical significance and genetic diversity of NDM-producing E. hormaechei. Enhanced surveillance, antibiotic stewardship and infection control measures are essential to mitigate the spread of these extensively drug-resistant pathogens.

PubMed ID

41179926

Volume

7

Issue

6

First Page

202

Last Page

202

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