Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Volume 32, Number 8—August 2026
Emerging Infection Networks Letter
Detection of blaOXA-23–Positive Proteus mirabilis Isolate, United States, 2024
Figure

Figure. Genomic comparisons of blaOXA-23–positive Proteus mirabilis detected in Massachusetts, USA, in 2024 to clinical isolates identified in previous studies. A) Genomic context of blaOXA-23 regions of P. mirabilis isolate detected in Massachusetts (2024DK-00154) and P. mirabilis clinical isolates previously identified in Switzerland (Pm1 and Pm5) and France (VAC). BLASTn (https://blast.ncbi.nlm.nih.gov) was used to identify the best match to the National Center for Biotechnology Information nucleotide database (https://www.ncbi.nlm.nih.gov/nucleotide) of the blaOXA-23-containing region. Genomic region comparison was generated using Easyfig (https://mjsull.github.io/Easyfig). Pink indicates antimicrobial resistance genes; blue indicates insertion sequences and transposon genes; yellow indicates other genes. Grey shading represents percent nucleotide sequence identity as indicated by the key. B) Phylogenetic tree based on core-genome alignment of blaOXA-23–positive P. mirabilis isolate detected in Massachusetts (2024DK-00154, in bold; GenBank accession no. CP194042) and blaOXA-23–positive P. mirabilis clinical isolates previously identified in other countries (GenBank accession nos. GCA_004347585.1a, GCA_004570075.1, GCA_004570775.1, GCA_004570785.1, GCA_008041895.1, GCA_009684595.1, GCA_009684635.1, GCA_030335585.1, GCA_030335605.1, GCA_030336025.1, GCA_039728795.1, GCA_042929925.1; genome assembly sizes min: 3.91 Mb; max: 4.11 Mb; average: 4.00 Mb). Core-genome alignment and construction of a maximum-likelihood tree were performed using Parsnp (https://github.com/marbl/parsnp). Tree was visualized using iTOL (https://itol.embl.de) and rooted at the midpoint. Country and source of isolate collection are specified. Filled blue circles represent sequence type (ST) 142 isolates; empty circles represent non-ST142 isolates. Year of isolate collection is provided when known. Blue box indicates ST142 isolate cluster. Scale bar indicates number of substitutions per nucleotide. Unk, unknown.