Study of the influence of Dr fimbriae on cell adherence to the surface of calcium oxalate and tribasic calcium phosphate crystals in various buffers - test tube test

Recent findings indicate that frequent urinary tract infections (UTIs) can lead to both infection and metabolic stones. However, the exact processes by which UTIs cause metabolic stones are still unclear . Due to the fact that Dr fimbriae are closely associated with uropathogenic strains of E. coli causing chronic urinary tract infections, it is interesting to investigate its impact on the bacteria adherence to the calcium oxalate and tribasic calcium phosphate – model elements of kidney stones. For this experiment, recombinant AAEC191A strains were used. Initially, all strains were suspended in following buffers: PBS pH=7.4, PBS pH=5.7, PBS+40 mM sodium oxalate pH=5.7, PBS+20 mM sodium oxalate pH=5.7, PBS+5 mM sodium oxalate pH=5, 7 and citrate buffer (21.75 mM sodium citrate, 8.25 mM citric acid, 120 mM sodium chloride., and brought to the same OD600. To examine the percentage adherence of cells to selected calcium salts, 5 ml of the aqueous phase was prepared, containing 0,5 ml, 1 ml, or 2 ml of culture suspended in the appropriate buffer, to which 1 ml of 20% suspension of tribasic calcium phosphate (hydroxyapatite) or calcium oxalate monohydrate was added at the end. Then, all samples were mixed for 10 minutes, allowing the bacteria to atach to the crystal suspension, which resulted in a loss of bacteria in the aqueous phase. No calcium salt suspension was added to the control samples; however, they were subjected to the same experimental conditions as the test samples. In the case of samples containing hydroxyapatite or calcium oxalate monohydrate suspension, the transition of bacteria to the suspension phase resulted in a decrease in the optical density, OD600, of the aqueous layer compared to the optical density of the corresponding control sample. The OD600 of each sample was measured in three technical replicates.
The catalog contains a Word document with graphs of the percentage of cell adherence of AAEC191A/pACYC177 and AAEC191A/pCC90 strains to monohydrate calcium oxalate crystals and to tribasic calcium phosphate in various buffers.