OXALATE-DEGRADING ACTIVITY OF FECAL BIOPTAT OF RATS AFTER CEFTRIAXONE TREATMENT
Akulenko I, Skovorodka M, Suslov G, Serhiychuk T, Tolstanova G
Taras Shevchenko National University of Kyiv,
ESC Institute of biology and medicine
It was found that during urolithiasis 70-80% of excreted stones were calcium oxalate, and the level of oxaluria depended in a certain way on the composition and functional activity of intestinal microbiota, in particular on their ability to degrade oxalates. The antibiotics decreased the quantity of oxalate-degrading bacteria (ODB), but there are no approaches to evaluate the total oxalate-degrading activity (ODA) of fecal microbiota (without isolation of pure culture).
The aim of the present study was to determine the quantity of ODB of fecal microbiota and to assess the dynamic changes in the ODA of fecal microbiota after ceftriaxone treatment in rats. The object of the study was a fecal microbiota of male Wistar rats (200-300 g, n = 6). Ceftriaxone (300 mg/kg, CJSC “Darnitsa”, Ukraine) was injected intramuscularly for 7 days. Feces were collected before antibiotic treatment and on the 1st, 14th and 56th days after antibiotic withdrawal. The quantity of ODB was determined by culture method on a highly selective Oxalate Medium (cultivated anaerobically at 37°C for 48 hours). The redoximetric titration (with KMnO4) was adopted to evaluate the total ODA of fecal microbiota. The results were expressed in % of degraded oxalate per 0.01 g of feces.
On the 1st day after ceftriaxone withdrawal, we observed both the increase of the quantity of ODB from lg 8.02±0.25 CFU/g to lg 9.47±0.17 CFU/g (p<0.05) and the fecal microbiota ODA from 9.50±1.78% to 11.67±2.99%. On the 14th day, there was a significant decrease of the ODB number (by more than 2 orders from lg 8.02±0.25 CFU/g to lg 5.72±0.48 CFU/g, p<0.05), that was accompanied with diminishing of the fecal ODA from 9.50±1.78% to 6.3±1.46%. On the 56th day, the ODB quantity left almost unchanged in comparison with the 14th day of experiment (lg 5.28±0.45 CFU/g, p<0.05), however, the fecal ODA decreased to 4.67±1.87% (p<0.05).
Ceftriaxone treatment reduced the total oxalate-degrading activity of fecal microbiota independently on the quantity of oxalate-degrading bacteria. The redoximetric titration (with KMnO4) had shown to be a reliable method for evaluation of the total oxalate-degrading activity of the fecal microbiota without the need for isolation of pure culture.