The role of Oxalobacter formigenes in calcium oxalate stone disease

Abstract

Calcium oxalate is the major component of about 75% of all urinary stones. Hyperoxaluria is a primary risk factor for calcium oxalate stone formation. The bioavailability of ingested oxalate and the extent of intestinal absorption of dietary oxalate are considered to be important factors in hyperoxaluria. Oxalobacter formigenes is a Gram-negative anaerobic bacterium that colonizes the intestinal tract. It is unique in that it requires oxalate both as an energy and carbon source. The only known factor which reduces colonization with O. formigenes is the treatment with antibiotics to which the bacterium has been reported to be sensitive. A deficiency of oxalate degradation by O. formigenes may increase urinary oxalate excretion, attributed to decreased intestinal oxalate degradation, leaving more oxalate available for absorption at a constant intestinal absorption rate. A lack of colonization with O. formigenes increases the risk of recurrent calcium oxalate stone formation. While evidence is emerging that orally administered O. formigenes can reduce urinary and plasma oxalate, the possible treatment with a probiotic still remains a challenge.