DOI: 10.3390/microorganisms14071428 ISSN: 2076-2607

Genomic Evidence for Mobile-Element-Associated Resistance: Predicted MOBH-Family Relaxase Sharing and Adjacent ICE-Cassette Architectures in the Pseudomonas guariconensis Clade

Fuad Alanazi, Abdulhadi M. Abdulwahed, Abdulrahman Alrezaihi, Mohammed Ali M. Marie, Alanoud T. Aljasham, Raed Farzan

We analysed nine Pseudomonas guariconensis-clade genomes from environmental and clinical sources across four continents to test whether carriage of acquired resistance is associated with the acquisition of mobile elements. FA-1, our tick-derived anchor from Hyalomma dromedarii on Saudi camels, sits at 87.52–87.94% ANI to the other genomes on the longest external branch of the core-genome ML phylogeny. In the current NCBI type-strain ANI taxonomy check, FA-1 is conspecific with the recently described Pseudomonas shiyinii type strain ST4 (98.05% ANI). The recently reported Vietnamese hospital-wastewater isolate KNHN1 groups within the sensu stricto clinical clade alongside USA-Nashville and India at 99.7%/99% (SH-aLRT/UFBoot) support. Across the nine genomes, three distinct carbapenemase architectures emerged: Dao (chromosomal KPC-2 + NDM-1 + AFM-5), Ethiopia (chromosomal NDM-1 × 2 + plasmid VIM-4), and Korea (plasmid VIM-2). Dao and Ethiopia chromosomes share a MOBH-family relaxase signal, extending the MOBH marker to the clinical compartment. MBL-positive genomes carried more mobile elements (Dao 55; Ethiopia 22; Korea 16; 16–55 hits) than MBL-negative comparators (0–8 hits), an unadjusted descriptive observation (n = 3 vs. 6). Ethiopia presented an integron-rich chromosomal and plasmid architecture (six structures), while Dao carried IS-bounded transposon islands on the chromosome. Three of four Dao chromosomal ICE predictions and one Ethiopia ICE prediction lay 27–50 kb from IS-bounded carbapenemase loci; a fourth Dao ICE was standalone and the major Ethiopia NDM-1 + OXA-10 cassette lacked an adjacent complete ICE prediction, indicating descriptive ICE-cassette proximity rather than functionally demonstrated mobility. Together, these findings are consistent with mobile-element acquisition as a plausible route for the emergence of clinical resistance within this clade, with environmental relatives retaining empty insertion sites at the AMR-cassette locus.

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