Abstract
Background: Enterohemorrhagic E. coli (EHEC) is known to be the main cause of bloody diarrhea and hemolytic uremic syndrome, therefore it is the main cause of acute renal failure resulting from food contamination, or undercooked food, it is one of the most common disease-producing strains in developing countries. The majority of cases of hemorrhagic intestinal diarrhea in humans are caused by the O157:H7 serotype
Aim: This study aimed to understand the pathophysiology of E. coli O157: H7 and how an experimental infection with this bacterium affects the histological structure of the kidneys in male mice at 8–12 weeks of age, as well as it attempts to determine the therapeutic effect of an approved drug (Trimethoprim-Sulfamethoxazole) in the treatment of bacteria and compare it with an antibiotic (Ciprofloxacin) which its effectiveness is tested in vitro.
Methods: The identification of the bacteria being studied and its classification is verified by isolating the bacteria using culture media and biochemical diagnosis by using Vitek device, antibiotic sensitivity test was carried out towards 10 antibiotics, calculation and determination of the bacterial count infectious dose and the half-lethal dose (LD-50) carried out by using Reed-Muench method, Glass slides of kidney tissue were prepared using the sectioning method
Results: bacteria were sensitive to Amikacin, Azithromycin, Ciprofloxacin, Metronidazole, Tetracycline, Gentamicin, Trimethoprim_Sulfamethoxazole, and Ceftriaxone. However, the bacteria demonstrated resistance to Amoxicillin/clavulanic acid and Ampicillin. Ciprofloxacin exhibited the highest level of sensitivity among the antibiotics tested, with Trimethoprim-Sulfamethoxazole placed second. Animals that have been intentionally infected with these bacteria exhibit various levels of clinical symptoms, including lethargy, withdrawal, loss of appetite, increased respiratory and heartbeat rates, and varying degrees of diarrhea. Other manifestations of paralysis may arise, as well as the incidence of several mortality in mice. The histological examination revealed acute atrophy in several renal glomeruli, fragmentation in others, and dilatation of the capsular or urinary space surrounding them. Additionally, there was narrowing of the cavities in some urinary tubules and disintegration of the epithelium that lines the parietal layer of Bowman's capsule. inflammatory cellular infiltration, Congestion, and hemorrhage were also observed In comparison to the other groups.
Conclusions: Trimethoprim-Sulfamethoxazole and Ciprofloxacin were active in stopping diarrhea, and regaining some activity of the mice, but the tissue lesions were still evident in the mice group that treated with Trimethoprim-Sulfamethoxazole and the other treated with the antibiotic Ciprofloxacin. the LD-50 dose group exhibited more severe levels of these symptoms. Regarding the groups that received the two antibiotics, their ability to stop diarrhea in mice was observed, although the mice still experienced various tissue damage including necrosis, degeneration, cellular infiltration, hyperplasia, congestion, and hemorrhage.

Key words: E. coli O157: H7 pathogenesis, antibiotic, drug, histological effect of E. coli O157: H7.