Elizabethkingia bruuniana strain Mich-4: molecular identification, genome analysis, resistome characterization, and virulence profiling
Year: 2026
Type: article
Abstract: Introduction Elizabethkingia bruuniana is an emerging opportunistic pathogen associated with severe human infections, yet its genomic diversity, antimicrobial resistance mechanisms, and virulence-associated traits remain poorly understood. Methods Here, we performed phenotypic characterization and comparative genomic analyses of E. bruuniana strain Mich-4, isolated from the upper respiratory tract of a patient in Michigan. Results MALDI-TOF MS misidentified the isolate as E. meningoseptica , whereas genome-based analyses using GTDB-Tk, average nucleotide identity (ANI), digital DNA–DNA hybridization (dDDH), and phylogenomics classified it as E. bruuniana . Comparative analysis of 12 E. bruuniana genomes revealed an open pan-genome comprising 6,301 gene clusters, including 3,062 core genes. Analysis based on Heaps’ law indicated substantial genomic plasticity. Further analysis of 47 representative Elizabethkingia genomes identified lineage-specific patterns of antimicrobial resistance and virulence-associated genes. Antimicrobial susceptibility testing showed that Mich-4 exhibited multidrug resistance but remained susceptible to trimethoprim-sulfamethoxazole and ciprofloxacin. Genomic analysis identified conserved intrinsic β-lactamase genes ( blaB , blaGOB , and blaCME ) together with determinants associated with aminoglycoside and chloramphenicol resistance, consistent with the observed β-lactam-resistant phenotype. Comparative analyses also demonstrated widespread conservation of genes involved in oxidative stress resistance, adhesion, capsule formation, lipopolysaccharide biosynthesis, metabolic adaptation, and urease production. A type VI secretion system subtype III (T6SSiii) and conserved ICEEa-like type B conjugative transfer loci were identified in most E. bruuniana genomes. Conclusion Collectively, this study provides a comparative genomic framework for understanding the evolution, antimicrobial resistance, and virulence-associated traits of E. bruuniana , while improving species identification and expanding genomic resources for future epidemiological and functional studies.
Institutions: Northern Illinois University, Michigan State University
Language: English
Subfield: Microbiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7225797021