Dependence of quantitative composition of oxalate-degrading bacteria in fecal biopsy of rats on the quantity of oxalates in the diet

Changes in the composition of intestinal microbiota, namely the reduction of microorganisms capable of metabolizing oxalates, is one of the main factors in the development of hyperoxaluria. The purpose of this study was to determine the quantity of oxalate-degrading bacteria in fecal biopsy of different species of laboratory animals and to investigate the relationship between the amount of oxalate in the diet and the level of oxalate-degrading bacteria. Methods. The object of the study was the content of oxalate-degrading bacteria in fecal biopsy of experimental animals: nonbreeding rats (n = 12); Wistar rats (n = 12); mice Balb C line (n =12); сhinchilla rabbits (n= 10). The quantity of oxalate-degrading bacteria was determined by culture method on a highly selective Oxalate Medium. Results. Current data shows that the content of oxalate-degrading bacteria in fecal biopsy depends on the species of the animals and the high content of oxalates in the diet. In Wistar line rats, oxalate-degrading bacteria were found in 100 % of the animals, in non-breeding rats – 58 %, in mice Balb C line – 42 %, in сhinchilla rabbits – 7 %. The highest quantity of oxalatedegrading bacteria in grams of fecal biopsy was found in Wistar rats – lg 6,12 ± 0,63 CFU/g, in non-breeding rats – lg 2,97 ± 0,34 CFU/g, in mice lg 2,4 ± 0,41 CFU/g. The least quantity of oxalate-degrading bacteria was detected in rabbits (lg 2,1 ± 0,5 CFU/g). A 14-day administration of Na2C2O4 to non-breeding rats has led to an increase in the quantity of oxalate-degrading bacteria in fecal biopsy. During the first seven days of the high-oxalate diet 57 % animals had increased the quantity of oxalate-degrading bacteria in a gram of feces. After 14 days, the further increase of oxalatedegrading bacteria in a gram of feces was observed in 25 % animals. In general, the quantity of oxalate-degrading bacteria during high-oxalate diet has increased by two orders. Conclusions. Animals with non-detectable level of oxalate-degrading bacteria in feces might be attributed to the potential risk group of hyperoxaluria and the formation of oxalate stones