Prevalence, Species Characterization, and Genetic Diversity of Bartonella Infections in Rodents From Mudflat Wetlands Along the Eastern Coast of Jiangsu Province in China.

Objective: To investigate the infection status, species composition, and genetic diversity of Bartonella in local rodent populations in coastal mudflat wetland habitats in eastern Jiangsu Province of China. Methods: From March to June 2023, rodents were captured in mudflat wetlands of Dongtai and Tinghu Counties, Eastern China. Rodent species were identified, and nucleic acids were extracted from liver and spleen tissues. The mitochondrial cytochrome b (mt-cytb) gene was amplified by PCR, while Bartonella-specific citrate synthase (gltA) and 16S rRNA genes were amplified by semi-nested PCR. Phylogenetic and homology analyses were conducted to identify rodent and Bartonella species. Results: Among 29 captured rodents, 26 were Apodemus agrarius and 3 were Mus musculus. Phylogenetic analysis of the mt-cytb gene divided A. agrarius into 7 lineages, each linked to geographically diverse Bartonella populations. Six A. agrarius rodents tested positive for Bartonella, with a positivity rate of 20.69%. Phylogenetic analyses revealed three Bartonella species: B. fuyuanensis, B. taylorii, and one undetermined species. The infected Bartonella strains clustered into three evolutionary branches based on gltA and 16S rRNA genes. Conclusions: This study provides the first evidence of Bartonella infection among rodent populations in wetland habitats along China's eastern coast. The region harbors diverse rodent species, with a high Bartonella infection rate, and at least three species were identified, including a potential novel species.