Between July 2024 and July 2025, we collected spleen samples from 119 wild rodents captured across various zoogeographical regions of Gwangju City, Republic of Korea, to screen for major zoonotic pathogens, including Anaplasma, Babesia, Bartonella, Borrelia, Coxiella, Ehrlichia, and Rickettsia species. Of these, 13 samples (10.92%) tested positive for Bartonella spp. The positive samples were cultured on blood agar, resulting in eight bacterial isolates. Internal transcribed spacer (ITS) gene sequencing and phylogenetic analysis confirmed all Bartonella-positive samples as B. grahamii. Antibiotic susceptibility testing revealed that all B. grahamii isolates exhibited multidrug resistance (MDR) to ciprofloxacin, nalidixic acid, cefoxitin, streptomycin, and tetracycline, and showed intermediate resistance to ampicillin. In contrast, the isolates were susceptible to ceftazidime, cefotaxime, ceftriaxone, imipenem, gentamicin, amikacin, azithromycin, chloramphenicol, and trimethoprim/sulfamethoxazole. These findings provide essential baseline data on the presence and resistance patterns of B. grahamii in wild rodent populations inhabiting peri-urban environments. The detection of MDR Bartonella strains underscores a potential public health concern, particularly regarding zoonotic spillover via ectoparasites such as ticks. Sustained molecular surveillance and antimicrobial resistance monitoring are warranted to mitigate future zoonotic threats.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    Trapping of rodents
    DNA extraction and PCR amplification of zoonoticpathogens
    Isolation of Bartonella species
    DNA sequencing and phylogenetic analysis
    Antibiotic resistance testing
    Statistical analysis
Results
    Epidemiology of zoonotic pathogens in mice capturedin Gwangju
    Molecular characterization and isolation of B. grahamii
    Antibiotic susceptibility of Bartonella Isolates
DISCUSSION
ACKNOWLEDGEMENTS
COMPETING INTERESTS
REFERENCES

• Hyungju Lim(Jeollanamdo Veterinary Service Laboratory, Gangjin, 59213, Korea)
• Yujin Kim(Division of Infectious Disease Investigation Health and Environment Research Institute of Gwangju, 584 Mujindae-ro, Seo-gu, Gwangju 61954, Korea)
• Sun-Hee Kim(Division of Infectious Disease Investigation Health and Environment Research Institute of Gwangju, 584 Mujindae-ro, Seo-gu, Gwangju 61954, Korea)
• Young-Bin Baek(Department of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)
• Sang-Ik Park(Department of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea) Corresponding author
• Gun Lee(Department of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea, Department of Veterinary Zoonotic Diseases, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)
• Chung-Do Lee(Department of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea, Department of Veterinary Zoonotic Diseases, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)
• Hyoun-Jeong Moon(Department of Veterinary Pathology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea, Department of Veterinary Zoonotic Diseases, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)
• Jun-Gyu Park(Department of Veterinary Zoonotic Diseases, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea) Corresponding author
• Dong-Min Kim(Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Korea)
• You Mi Lee(Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Korea)
• Jun-Bong Lee(Department of Veterinary Public health, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)
• Bock-Gie Jung(Department of Veterinary Microbiology, College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)