Comparative Transcriptome Analysis of Bartonella Species from Diverse Hosts Reveals Evolutionary Insights — Global, 2023–2025

What is already known about this topic? Transcriptomic approaches have been used in phylogenetic studies of eukaryotes, yet their application to prokaryotic organisms remains limited. To date, research on species differentiation and phylogenetic relationships within Bartonella spp. has relied primarily on genomic data, and the taxonomic relationships among species in this genus remain poorly resolved. What is added by this report? The transcriptome of Bartonella spp. varies based on species and host origins and exhibits systematic differences. Transcriptome-based phylogenetic analysis reveals that strains cluster by species and host origin. This pattern indicates that differentiation by species and genetic evolution of Bartonella is predominantly shaped by the host origin. What are the implications for public health practice? Our study confirms that transcriptomics is an effective tool for determining differentiation and evolutionary relationships among Bartonella spp. and demonstrates its potential applicability to studies of other prokaryotic species.