Genomic and antimicrobial susceptibility characterization of a clinical Pasteurella aerogenes isolate from a human patient.

BACKGROUND

Pasteurella aerogenes is an opportunistic zoonotic pathogen associated with reproductive disorders in animals and sporadic human infections. However, the complete genome, antimicrobial susceptibility profile, and phylogenetic relationships of clinical P. aerogenes isolates, particularly from China, remain poorly understood.

METHODS

We sequenced the complete genome of the clinical P. aerogenes isolate 21PA20240911 from a patient with urinary tract infection in Hainan, China, using a hybrid PacBio and Illumina sequencing approach. Comparative genomic analyses, including genome feature characterization, ANI-based species delineation, virulence gene screening, antimicrobial susceptibility testing, and cgSNP-based phylogenetic analysis, were performed to investigate the strains genomic landscape and evolutionary origin.

RESULTS

The genome of strain 21PA20240911 was 2.3Mbp with a G+C content of 40.84%. ANI analysis confirmed its taxonomic assignment as P. aerogenes (97.61% identity with the reference strain). The strain carried 28 virulence-associated genes. Notably, tviB and wbpD were detected only in our strain and a duck-derived Sichuan isolate. The isolate was resistant only to erythromycin but showed nonsusceptibility to multiple β-lactams and tetracyclines. Resistance-associated determinants included tet (B)/tetR and a putative PBP3/FtsI-like protein variant carrying D350N and S357N substitutions. Phylogenetic analysis tentatively suggests the possibility of zoonotic transmission from local poultry for this strain.

CONCLUSION

This study provides the first complete genome sequence of a clinical P. aerogenes isolate from China, offering a genomic foundation for understanding its pathogenicity and antimicrobial resistance. From a One Health perspective, enhanced surveillance in both clinical and veterinary settings is warranted.