Genotypic characterization of Escherichia coli isolated from infected chicken in Basrah, Iraq

This study aimed to detect the presence of Escherichia coli in broiler and layer hens in the Basrah province, Iraq using macroscopic and microscopic diagnosis and bacterial isolation that causes infection insome internal organs (liver and heart), and by polymerase chain reaction. Randomly chosen samples were taken from different places within Basrah province for further investigation (poultry fields in Al-Qurnah and Al-Hartha). The bacteriological analysis revealed that the presence of Escherichia coli is responsible for causing fibrinous pericarditis and perihepatitis in birds. The macroscopic examination revealed hemorrhagic lesions and a significant buildup consisting of a white fibrous accumulation in the pericardial sac of the infected birds' hearts. The livers of infected birds exhibited significant deposition of white fibrous exudate on the liver surface, along with hepatomegaly. The afflicted heart displays a microscopic appearance marked by a notable aggregation of inflammatory cells in the pericardial sac and the release of fibrinous exudate. Additionally, there is an accumulation of edematous exudate in the cardiac muscle fibers, accompanied with congestion of blood vessels in the myocardium. The microscopic examination of the infected liver revealed the existence of a significant infiltration of inflammatory cells in the liver capsule, as well as the presence of a thick fibrinous exudate encapsulated on the liver surface and congestion of the central vein. The histological analysis of the affected heart and liver revealed a significant buildup of collagen and fibrin fibers, which exhibit a prominent dark bluish staining. This buildup is widely distinguished in the pericardial and hepatic capsules. The study indicated that fibrinous pericarditis and perihepatitis affected birds, as indicated by the examination of bacterial results. Escherichia coli emits endotoxins that induce vascular damage in the heart and liver, resulting in an elevated presence of fibrin exudate around the affected tissue. The histological analysis supported this conclusion. Keywords: Fibrinous, Pericarditis, Perihepatitis, Pathology, Biological.