Nosocomial infections have serious effects on health conditions in humans and animals. The present study aimed to investigate the pathogenesis of Enterobacter cloacae post intraperitoneal inoculation in rabbits to investigate the immunological and possible pathological effects. A total of 42 rabbits were randomly divided into two equal groups (n=21). The first group was inoculated with 3×108 CFU/ml of the virulent isolate of E. cloacae intraperitoneally (IP), while the second group was injected IP with phosphate buffer saline and considered a control negative group. The animals were sacrificed at different time post-infection at 48/72 h, and at day 7 post-bacterial inoculation. The results revealed a significant increase in the concentration of TNF-α, especially in the infected groups. In addition, there were different pathological lesions in different organs of animals, mainly in the infected groups, which represents by vascular congestion and edema with polymorphoneutrophiles infiltration in the lungs, kidneys, and heart. This study is considered the first trial which aimed to observe the pathological changes of E. cloacae in vital organs in rabbits.
Keywords: Histopathology; Immune responses; Pathogenesis; Enterobacter cloacae.