Studies suggest that the gut microbiome may play a role in calcium stone formation, and may therefore present a novel treatment approach. A low level of Oxalobacter formigenes has been identified as a risk factor for calcium oxalate stone formation.

O. formigenes breaks down oxalates in the gut, and if O. formigenes levels are low, oxalate levels can accumulate in the kidneys and potentially form calcium oxalate stones. The presence of O. formigenes is associated with a 70% reduction in the risk of recurrent kidney stones .

-Diminished O. formigenes colonization in the gut of urinary stone forming subjects was associated with reduced bone mineral density.

-Males carry O. formigenes at significantly lower abundance than females. This correlates with the higher kidney stone incidence in males compared to females.

Treatment options:

• A low oxalate diet: A diet low in oxalate is suggested to reduce urinary oxalate formation. Foods high in oxalate include: spinach, nuts/nut butters, beets, potatoes, rhubarb. Research suggests that dietary oxalate consumption must be reduced to 80 - 100 mg/day in order to be effective.
• Avoid calcium in supplement form: Calcium supplementation has been found to increase kidney stone risk. However, normal calcium intake through dietary sources did not, as this can help bind oxalates in the digestive tract.
• Recommend a low-fat diet: A low-fat diet is suggested to help limit the effects of bile acids on oxalate absorption in the colon.
• Avoid antibiotics to which O. formigenes is known to be sensitive, including: Azithromycin, Ciprofloxacin, Clarithromycin, Clindamycin, Doxycycline, , Gentamicin, Levofloxacin, Metronidazole, Tetracycline.
• Check bone density: Diminished O. formigenes colonization in the gut of urinary stone forming subjects was associated with reduced bone mineral density.

- Our research team was not able to find negative outcomes of increased Oxalobacter formigenes levels in the gut at this point. Most of the existing studies and research papers are addressing the positive effects of Oxalobacter formigenes in the gut, namely their ability to be able to reduce the incidence of kidney stones. Further investigation and research is needed to be able to interpret levels above the normal reference ranges.

- An increased level of Oxalobacter formigenes may be due to high levels of probiotics intake that are commonly found in yogurt and kefir as well as probiotic formulations.