Activity of probiotics from food origin for oxalate degradation.

Kidney stones composed of oxalate are a significant health problem. It has been suggested that modification of the intestinal microbiota to reduce the amount of oxalate in the digestive system could be an effective treatment. There have been several studies into the use of lactic acid bacteria for the degradation of intestinal oxalates. We isolated 88 lactic acid bacteria strains from a range of dairy products, and screened for their ability to degrade oxalate. Using the oxalate-degrading Enzymatic Activity Index and the viable cell counts, five strains of Lactobacillus fermentum and two strains of Lactobacillus gastricus were identified as having strong oxalate degradation abilities, and were further investigated. All seven strains were able to tolerate acid (pH 4 and 3), bile salts (0.3%), phenol (0.3%), and to produce exopolysaccharides. They were resistant to a wide range of antibiotics. Among these strains, Lactobacillus fermentum NRAMJ5 and Lactobacillus gastricus NRAMJ2 were, therefore, good candidates as probiotics for managing hyperoxaluria.