Introduction. Oxalobacter formigenes, as a gram-negative anaerobic bacterium, metabolizes oxalate in the intestine by the enzymes oxalyl-CoA decarboxylase (OXC) and formyl-CoA transferase (FRC). Therefore, not only the presence of the bacterium but also microbial load may affect intestinal absorption and urinary exertion. We evaluated the relationship between Oxalobacter formigenes load and the formation of calcium oxalate urolithiasis using quantitative molecular methods. Methods. By clinical manifestation and stone analysis, we selected the urine and stool specimens of 73 patients with calcium oxalate urolithiasis. First, the gene regions of the two genes FRC and OXC in Oxalobacter formigenes were selected utilizing bioinformatics and specific primers designed for these regions. Following DNA extraction from stool specimens by specific primers of each gene, PCR was carried out and positive samples were sequenced. Then, qPCR was applied to determine the effective load of Oxalobacter. Also, biochemical tests were performed to measure the excretion rate of oxalate in urine specimens. Results. In addition to oxalobacter identification by PCR, the load of bacteria was quantitatively assessed using qPCR by specific primers for both FRC and OXC gene regions. A significant negative relationship had found between the formation of calcium oxalate urolithiasis and the presence of Oxalobacter formigenes in patients with kidney stone disease. The mean excretion of oxalate and citrate in urolithiasis cases were 22. 93 and 552. 106 mg/24h, respectively. Conclusion. The presence of Oxalobacter formigenes can highly inhibit the generation of calcium oxalate urolithiasis. Furthermore, molecular techniques are more effective than other methods such as culture for the isolation of this bacterium.

The gut microbiota (GM) is currently considered as a pathogenic factor in a number of diseases. It is known that some gastrointestinal diseases cause a high risk of developing urolithiasis. The study gives modern data demonstrating the influence of the GM, in particular Oxalobacter formigenes, on the formation of oxalate kidney stones. The relationship between the presence of inflammatory bowel diseases and the use of antimicrobial drugs with oxalate homeostasis was demonstrated, methods for correcting the GM in patients with urolithiasis, including the use of probiotics and diet therapy, were analyzed. The studies presented in the article demonstrate that the correction of the GM can be considered as a therapeutic goal and be an actual component of the complex treatment and metaphylaxis of nephrolithiasis.

Background: Urinary stones are a major problem world, and their incidence has increased signifi cantly in recent years. Objectives: This study aimed to develop a simple and rapid molecular method based on PCR and qPCR assays to detect Oxalobacter formigenes (which causes oxalate degradation in intestines) in fecal samples of healthy volunteers and patients with calcium oxalate nephrolithiasis, and determine the amount of urinary oxalate in the two groups. Methods: This study was performed on urine and fecal samples of 73 patients with kidney stones and 52 healthy individuals. After DNA extraction, PCR and qPCR assays were performed on two gene regions of O. formigenes, OXC, and FRC. Also, urine oxalate was measured in the study population using biochemical methods. Results: We found that the presence of O. formigenes could reduce the risk of kidney stones and calcium oxalate stones. In fact, both FRC and OXC genes were involved in the diagnosis of O. formigenes; however, the results based on the FRC gene showed higher effi ciency. In addition, the presence or absence of stones did not aff ect the amount of urinary excretion of oxalate, rather it is aff ected by diet. Conclusions: Molecular identifi cation of O. formigenes by PCR and qPCR assays allows rapid, specifi c, and reproducible detection in fecal samples, which also allows immediate processing of these samples in clinical conditions.

Background and Objectives: The majority of all kidney stone cases are oxalate urolithiasis with a high risk of recurrence. Beside its widespread occurrence, kidney stones are characterized by severe complications and high treatment costs. Probiotics and herbal medications could be forthcoming therapeutic interventions in the management of oxalate kidney stones. Materials and Methods: The PubMed/MEDLINE database was searched for keywords “Oxalobacter formigenes” AND “Oxalate” OR “oxalate degradation” AND “Lactobacillus” OR “Bifidobacterium” OR “recombinant Lactobacillus” OR “Bacillus subtilis”, and “urolithiasis” AND “herbal extract”. The search returned 253 results, 38 of which were included in the review. Results: Most of the oxalate-degrading probiotics belong to the Oxalobacter formigenes, Lactobacillus, Bifidobacterium, and Bacillus genus with a minimum dosage of 107 CFU in the form of capsules, sachets, and lyophilized powder. Oxalate concentration in media was 5-50mM with an incubation time ranging from 24h to 14 days. The majority of the studies suggested that probiotic supplementation might be useful for reducing urinary excretion of oxalate and urea and alleviation of stone formation. Different herbal extracts were used on murine models of nephrolithiasis (induced by 0.5-3% ethylene glycol) with reduction of renal inflammation and urinary parameters, and calcium oxalate crystals. Conclusion: Several strains of probiotics and herbal extracts confer protective effects against kidney stone/nephrolithiasis, indicating their promising nature for being considered as elements of preventive / adjuvant therapeutic strategies.

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