Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 13 1 2025 02 16 28 32 Mona Hamedi Department of immunopathology, Faculty of veterinary medicine, Islamic Azad University, Science and research branch, Tehran, iran Hossein Esmaeili Department of microbiology and immunology, Faculty of veterinary medicine, university of Tehran, Tehran, Iran. Iradj Ashrafi Tamai Department of microbiology and immunology, Faculty of veterinary medicine, university of Tehran, Tehran, Iran. Mohammad Reza Moradbakhsh Student of veterinary medicine, Faculty of veterinary medicine, Islamic Azad University, Science and Research branch, Tehran, Iran. Mohammad Davoudi Student of veterinary medicine, Faculty of veterinary medicine, Islamic Azad University, Science and Research branch, Tehran, Iran. 2024 11 14 2024 11 17 Background:   Truperella pyogenes (T. pyogenes) is a gram-positive bacterium which can lead to visceral abscesses in cattle. The abscesses may be found in internal organs such as spleen, kidney, liver, lungs and skin. The aim of this study is to focus on spleen abscesses due to T. pyogenes. Methods:   The whole spleen was sent to the laboratory and the causative agent was evaluated using isolation methods and biochemical tests based on the colonies. Results:   The appearance of isolated colonies and the results of biochemical tests confirmed the presence of T. pyogenes in the spleen lesions. Conclusion:   The current results identified T. pyogenes as the only isolated bacterium in a case of visceral abscess. This study emphasizes the necessity of implementing effective planes such as improving sanitation, reducing stressful conditions, feeding cattle by balanced diet, avoiding sudden changes in grain intake, and controlling other diseases to prevent the chronic economical losses of visceral infection with T. pyogenes. https://jmb.tums.ac.ir/index.php/jmb/article/view/546