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. EHEC 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, as well as to determine the therapeutic effect of an approved drug (Trimethoprim-Sulfamethoxazole) in the treatment of bacteria and compare it with an antibiotic (Ciprofloxacin) whose effectiveness is tested in vitro.

Methods:
Identification of the bacteria being studied and their classification is verified by isolating the bacteria using culture media and biochemical diagnosis using the Vitek device. An antibiotic sensitivity test was carried out for 10 antibiotics, calculation and determination of the bacterial count infectious dose, and the half-lethal dose (LD-50) were carried out by using the Reed–Muench method. Glass slides of kidney tissue were prepared using the sectioning method.

Results:
Bacteria were sensitive to most antibiotics used except Amoxicillin/clavulanic acid and ampicillin, to which they showed resistance. 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, while histological examination revealed acute atrophy in several renal glomeruli, fragmentation in others, and dilatation of the capsular or urinary space, narrowing in some urinary tubules cavities, disintegration of the epithelium, inflammatory cellular infiltration, congestion, and hemorrhage in comparison to the other groups.

Conclusion:
Trimethoprim-Sulfamethoxazole and Ciprofloxacin were active in stopping diarrhea, and, regaining some activity in the mice, but tissue lesions were still evident in the mice group treated with Trimethoprim-Sulfamethoxazole and the other group 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 was observed, although the mice still experienced various types of tissue damage.

Key words: E. coli O157: H7 pathogenesis, Kidney, Antibiotic, Drug, Histological effect of E. coli O157: H7