Genomic analysis reveals two dominant strains of Ornithobacterium rhinotracheale in Austria and Hungary with distinct multidrug resistance profiles

Title (eng)
Genomic analysis reveals two dominant strains of Ornithobacterium rhinotracheale in Austria and Hungary with distinct multidrug resistance profiles
Author
Nicola Palmieri
Author
Claudia Hess
Author
Boglarka Pollak
Author
Tibor Magyar
Author
Krisztina Pinter
Author
Marianna Doman
Author
Ivana Bilic
Author
Michael Hess
Abstract (eng)
Ornithobacterium rhinotracheale (ORT) is an emerging pathogen that poses significant challenges to commercial poultry production due to respiratory and systemic infections, leading to economic losses. Increasing multidrug resistance further complicates effective treatment strategies. Here, we present the first large-scale genomic analysis of ORT isolates from Europe, focusing on 94 newly sequenced isolates from Austria and Hungary. Phylogenetic analysis revealed two dominant clades, O1 and O2, which included isolates from both regions, indicating a lack of geographic segregation. Both clades display high genetic similarity, indicating that each represents a single strain. Notably, Clade O1 appears to be specific to Europe and exhibits higher resistance to several antibiotics compared to Clade O2. Genome-wide association studies and database screening identified resistance genes linked to beta-lactam antibiotics (ccrA/orr) and tylosin (ermF/ermD). Despite the widespread presence of tetX and tetQ, these genes did not consistently predict tetracycline resistance. Furthermore, we identified the insertion sequences IS4351 and IS1380 as key mobile elements mediating the co-localization of tetX and ermF/ermD resistance genes within ORT isolates of Clade O1. These findings enhance our understanding of ORT’s genetic diversity, strain distribution, and resistance mechanisms, providing a basis for improved monitoring, vaccine development, and targeted interventions. The limited genetic variability observed in our data set underscores the challenges of identifying resistance genes and highlights the need for novel approaches to fully elucidate resistance mechanisms.
Keywords (eng)
Ornithobacterium RhinotrachealeMultidrug ResistanceWhole-genome SequencingPhylogeneticsResistance GenesMobile Genetic ElementsGWAS
Type (eng)
journal article
Language
[eng]
Persistent identifier
https://phaidra.vetmeduni.ac.at/o:4911
DOI
10.1128/aem.00569-25
Is in series
Title (eng)
Applied and Environmental Microbiology
Volume
91
Issue
8
ISSN
1098-5336
Issued
2025
Number of pages
21
Publication
American Society for Microbiology
Version type (eng)
version of record (published version)
Date issued
2025
Access rights (eng)
open access
License
CC BY 4.0 International
Rights statement (eng)
© 2025 Palmieri et al.