Background and Aim: The present study aimed to investigate the pathogenic ability of Cronobacter sakazakii in neonatal mice through the evaluation of its effect on liver tissue and the associated histopathological changes . Methods: Isolates of C. sakazakii were obtained from the Microbiology and Molecular Laboratory, College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad, and were confirmed by 16S rRNA sequencing from samples of infant formula, spinal fluid, and blood. Forty-five neonatal mice aged between 10 and 16 days were obtained from the Iraqi Center for Cancer and Medical Genetics. The animals were divided into three experimental groups, the first group as a control and given only distilled water, the second and third group 10³ cells/ml , 10⁵ cells/ml administered of C. sakazakii (AIC) . Liver tissues were collected from the animals, processed for histopathological examination, sectioned, stained. Results: The results showed liver tissue was found represented by types of necrosis, including focal necrosis, hydropic and ballooning degeneration, swelling of liver cells vacuolated degeneration, congestion in blood vessels, extensive and diffuse hemorrhage , absent of normal structure of the liver cords, as well as The presence of many inflammatory cells in the liver is a sign of chronic inflammation . Conclusion: The study shows C. sakazakii causes severe liver damage in neonatal mice, linked to virulence factors OmpA and OmpX that aid adhesion and invasion. Though rare, infections are fatal in preterm infants. This model advances research on mechanisms, progression, and treatment.
