Isolation and Immunopathological Evaluation of Chromobacterium violaceum from Diarrheic Chickens

<ns7:p> Background <ns7:italic>Chromobacterium violaceum</ns7:italic> is a rare but potentially pathogenic bacterium that can infect humans and animals. Limited information is available about its occurrence in poultry. This study aimed to isolate and identify <ns7:italic>C. violaceum</ns7:italic> from diarrheic chickens and to evaluate its immunological impact in a mouse model. Methods Fifty chicken diarrhea fecal samples were cultured and typed by biochemical tests, Vitek 2 Compact System, and 16S rRNA gene PCR sequencing. Killed bacterial antigens were prepared and administered to mice to measure immune responses (IgG and IL-6 levels by ELISA). The <ns7:italic>Aloe vera</ns7:italic> extract (100 mg/ml) was co-administered with the antigen to evaluate its immunomodulatory effect. A histopathological study of the liver, kidney, spleen, and intestine following experimental infection was conducted to detect tissue alterations. Results <ns7:italic>C. violaceum</ns7:italic> was cultured and diagnosed using molecular methods. Pathological changes in the liver, kidney, and intestine, such as necrosis and inflammatory cell infiltration, were significantly observed in infected mice. Immunological analysis revealed antibody response alterations and organ lesion scoring compared to controls. Conclusions This is the initial report on isolating and identifying <ns7:italic>C. violaceum</ns7:italic> from Iraqi poultry. The findings highlight its pathogenicity, zoonotic potential, and impact on signaling surveillance and preventive control in poultry production. </ns7:p>