Effect of a Probiotic Supplement Containing Lactobacillus Acidophilus and Bifidobacterium Animalis Lactis on Urine Oxalate in Calcium Stone Formers with Hyperoxaluria: A Randomized, Placebo-controlled, Double-blind and In-vitro Trial.

PURPOSE: To determine the effect of a probiotic supplement containing native Lactobacillus acidophilus (L. acidophilus) and Bifidobacterium animalis lactis (B. lactis) on 24-hour urine oxalate in recurrent calcium stone formers with hyperoxaluria. Moreover, the in-vitro oxalate degradation capacity and the intestinal colonization of consumed probiotics were evaluated. MATERIALS AND METHODS: The oxalate degrading activity of L. acidophilus and B. lactis were evaluated in-vitro. The presence of oxalyl-CoA decarboxylase (oxc) gene in the probiotic species was assessed. One hundred patients were randomized to receive the probiotic supplement or placebo for four weeks. The 24-hour urine oxalate and the colonization of consumed probiotics were assessed after weeks four and eight. RESULTS: Although the oxc gene was present in both species, only L. acidophilus had a good oxalate degrading activity, in-vitro. Thirty-four patients from the probiotic and thirty patients from the placebo group finished the study. The urine oxalate changes were not significantly different between groups (57.21 ± 11.71 to 49.44 ± 18.14 mg/day for probiotic, and 56.43 ± 9.89 to 50.47 ± 18.04 mg/day for placebo) (P = .776). The probiotic consumption had no significant effect on urine oxalate, both in univariable (P = .771) and multivariable analyses (P = .490). The consumed probiotics were not detected in the stool samples of most participants. CONCLUSION: Our results showed that the consumption of a probiotic supplement containing L. acidophilus and B. lactis did not affect urine oxalate. The results may be due to a lack of bacterial colonization in the intestine.

Association of intestinal oxalate-degrading bacteria with recurrent calcium kidney stone formation and hyperoxaluria: a case-control study.

OBJECTIVES: To investigate potential oxalate-degrading bacteria, including Oxalobacter formigenes, Lactobacillus (Lac) and Bifidobacterium (Bif) genera, and Oxalyl-CoA decarboxylase (oxc) encoding Lac (LX) and Bif (BX) species in participants with recurrent calcium kidney stones, and their correlation with 24-h urine oxalate. PARTICIPANTS AND METHODS: Stool and 24-h urine samples were collected from 58 patients with urolithiasis (29 cases with and 29 without hyperoxaluria) and 29 healthy controls. Absolute quantitation and relative abundance of the bacteria were measured by real-time PCR. The relationship between the investigated bacteria and 24-h urine oxalate were assessed statistically. RESULTS: The count per gram of stool and relative abundance of O. formigenes, Lac, Bif, LX and BX and the number of participants carrying O. formigenes, LX and BX bacteria were not significantly different between the groups; however, the relative abundance of O. formigenes in the kidney stone group was lower than in healthy controls (P = 0.035). More healthy controls were O. formigenes-positive compared with participants in the kidney stone group (P = 0.052). The results of the linear regression model, including all study participants, showed that the presence of O. formigenes could decrease 24-h urine oxalate (ß = -8.4, P = 0.047). Neither Lac and Bif genera nor LX and BX species were correlated with calcium stones or urine oxalate. CONCLUSION: These results emphasize the role of O. formigenes in kidney stone formation and its role in hyperoxaluria, which may be independent of kidney stone disease. Moreover, our results suggest that, although some Lac and Bif strains have oxalate-degrading potential, they may not be among the major oxalate-degrading bacteria of the gut microbiome.