The role of Oxalobacter formigenes colonization in calcium oxalate stone disease

Abstract

About 75% of urinary stones contain oxalate. As Oxalobacter formigenes is a Gram-negative anaerobic bacterium that degrades oxalate in the intestinal tract, we assessed the role of O. formigenes in oxalate metabolism by evaluating its intestinal absorption, plasma concentration, and urinary excretion. Of 37 calcium oxalate stone formers, 26 tested negative for O. formigenes and were compared with the 11 patients who tested positive. Patients provided 24-h urine samples on both a self-selected and a standardized diet. Urinary oxalate excretion did not differ significantly on the self-selected diet, but was significantly lower in O. formigenes-positive than in O. formigenes-negative patients under controlled, standardized conditions. Intestinal oxalate absorption, measured using [(13)C₂]oxalate, was similar in the patients with or without O. formigenes. Plasma oxalate concentrations were significantly higher in noncolonized (5.79 μmol/l) than in colonized stone formers (1.70 μmol/l). Colonization with O. formigenes was significantly inversely associated with the number of stone episodes. Our findings suggest that O. formigenes lowers the intestinal concentration of oxalate available for absorption at constant rates, resulting in decreased urinary oxalate excretion. Thus, dietary factors have an important role in urinary oxalate excretion. The data indicate that O. formigenes colonization may reduce the risk of stone recurrence.

Response of Germfree Mice to Colonization by Oxalobacter formigenes and Altered Schaedler Flora

“…Recent evidence suggests that a lack of colonization with the specialist oxalate-degrading bacterium O. formigenes increases the risk of recurrent calcium oxalate stone disease (1,2). Protection from calcium oxalate stone disease appears to be due to the oxalate degradation that occurs in the gut with low-calcium diets, with a possible additional contribution from intestinal oxalate secretion (13,21,44).…”

“…Recent evidence suggests that a lack of colonization with this oxalate-degrading specialist is a risk factor for idiopathic recurrent calcium oxalate stone disease (1,2). A review of worldwide data indicated that 38% to 77% of a normal population and only 17% of stone formers were colonized with O. formigenes (1).…”

Gut microbiome and chronic prostatitis/chronic pelvic pain syndrome

“…In addition, alterations in the normal stool microbiome have shown correlations with the presence of urologic diseases as with many other areas of the body that are thought to be physically distinct from the gut (73). For example, patients with renal calcium oxalate stones have been shown to have decreased Oxalobacter formigenes in the gut microbiome, a bacterial known to degrade dietary oxalate and thus is thought to at least be partially irresponsible for lower levels of urinary oxalate (74)(75)(76). Unfortunately a mechanistic relationship between the gut microbiome and urologic disease is not always so straightforward to discern.…”

Oxalobacter formigenes Colonization and Oxalate Dynamics in a Mouse Model

“…A review of colonization frequencies conducted worldwide indicated that 38% to 77% of a normal population is colonized with O. formigenes (7). Recent evidence suggests that a lack of colonization with this oxalate-degrading specialist is a risk factor for idiopathic recurrent calcium oxalate kidney stone disease (8,9). Controlled diet studies in healthy human subjects have also indicated that O. formigenes-colonized individuals excrete significantly less oxalate in 24-hour urine collections when they consume diets containing moderate oxalate (250 mg) and low calcium (400 mg) levels (10).…”