Virulence-associated Genome Sequences of Pasteurella canis and Unique Toxin Gene Prevalence of P. canis and Pasteurella multocida Isolated from Humans and Companion Animals

BACKGROUND: Comparative analysis of virulence factors (VFs) between Pasteurella canis and Pasteurella multocida are lacking, although both cause zoonotic infections. We determined the virulence-associated genome sequence characteristics of P. canis and assessed the toxin gene prevalence unique to P. canis among clinical isolates of P. canis and P. multocida. METHODS: We selected 10 P. canis and 16 P. multocida whole-genome sequences (WGSs) from the National Center for Biotechnology database. The VFanalyzer tool was used to estimate P. canis-characteristic VFs. Amino acid sequences of VFs were compared with multiple-aligned sequences. The genome structure containing P. canis-characteristic and adjacent loci was compared to the corresponding P. multocida genome structure. After designing primer sequences and assessing their accuracy, we examined the gene prevalence of the P. canis-characteristic VFs using PCR among clinical isolates of P. multocida and P. canis. RESULTS: Using VFanalyzer, we found virulence-associated cytolethal distending toxin (cdt)A–cdtB–cdtC loci common to all P. canis WGSs that were not found in P. multocida WGSs. Similarities in the multiple alignments of CdtA–CdtB–CdtC amino acid sequences were found among the 10 P. canis WGSs. Shared or similar loci around cdtA–cdtB–cdtC were identified between the P. canis and P. multocida genome structures. The PCR-based cdtA–cdtB–cdtC prevalence differed for P. canis and P. multocida clinical isolates. CONCLUSIONS: P. canis-specific cdtA–cdtB–cdtC prevalence was identified among clinical isolates. These three loci may be unique toxin genes and promising targets for the rapid identification of P. canis in clinical settings.