Introduction: The renal stone is a global health problem and nowadays, it has a high prevalence around the world.  Hyperoxaluria is one of the most important factors for calcium oxalate stone formation that is characterized with high level of oxalate excretion in urine. It is estimated that about 80% of renal stones have an oxalate origin, and one way for preventing renal stones in human body is its degradation by gastrointestinal bacterial such as oxalobacter formigenes, lactobacillus and bifidobacter. There are many reports using probiotics to preven renal stones. Up to now, no bacterium that is proficient in body oxalate degradation as probiotic has been recommended, In this survey for the first, time we evaluating the effects of specific oxalotroph bacteria Ammoniphilus oxalaticus DIM in reductionof the hyperoxaluria risk.

Materials & methods: We induced exogenous hyperixaluria by adding ammonium oxalate 3%in rat diet. 12 male Wistar rat were randomly divided into three groups. Rats in the control group received the usual diet during the study. Negative controls were added to the diet of ammonium oxalate and ammonium oxalate in addition to the positive control bacteria levels were 2×1o⁹ cfu. Measurement of urinary biochemical factors on (-5, 0, 5, 10, 15, and 20) rats were transferred to metabolic cages and 24-hour urine samples were collected. The volume and acidity of the urine were measured and urinary oxalate levels were calculated by the kit. The results were analyzed by Post hoc multiple comparison test.

Findings: Biochemical results showed the significantly reducing rate of urinary oxalate excretion at the positive control group in 3, 5 and 6th stages of sampeling. We didn’t observe any clinical symptoms between the examined rats.

Discussion & Conclusions: Regarding positive effect of Ammoniphilus oxalaticus  DIM in reducing the rate of urine oxalate excretion and risk of hyperoxaluria, it  would  be a good candidate for prevention of kidney stones with calcium oxalate kidney stone and it is hoped that in case of positive pathological studies, these bacteria could be used to reduce the risk of disease in humans