Presentation Authors: Jennifer Bjazevic*, Kaitlin F. Al, Jaswanth Gorla, Hassan Razvi, Jeremy P. Burton, LONDON, Canada
Introduction: Exposure to both urinary bacteria and antibiotics may impact the formation of calcium-based stone disease. Prior epidemiological studies have shown a strong association between the development of stone disease and a history of culture-proven urinary tract infections treated with antibiotics. We aimed to further evaluate the potential effect of a non-urease producing bacteria isolate from a urinary tract infection, and treatment with the antibiotic ciprofloxacin, on the formation of calcium oxalate stones utilizing a Drosophila melanogaster (DM) fly model.
Methods: DM flies were treated with a combination of a non-urease producing strain of Escherichia coli UTI89 and 0.1% sodium oxalate food for the duration of the 14-day assay (n=30 per group). Treatment with ciprofloxacin occurred on day 5-7 of the assay at a sub-minimum inhibitory concentration of 0.2 Î¼g/mL. DM control groups without the addition of UTI89 or ciprofloxacin were included for comparison. Inoculation with UTI89 was confirmed by culturing pulverized flies on lysogeny broth agar plates on days 1-5. Stone burden was assessed with a survival curve analysis and measured pixel intensity of dissected Malpighian tubules under birefringent microscopy.
Results: UTI89 was cultured at a minimum concentration of 3x103 colony forming units/fly for up to three days post exposure in treated flies. There was a trend towards decreased survival in oxalate food treated flies for days 15-35; however, UTI89 treatment did not affect fly survival. Preliminary results suggest that at day 7 exposure to UTI89 increased calcium oxalate crystal production in Malpighian tubules (p=0.001), and treatment with ciprofloxacin attenuated this effect (p=0.012, Figure 1). Similar trends were observed at day 14; however, these results did not reach statistical significance (Figure 1).
Conclusions: Our findings further suggest that exposure to both a non-urease producing E. coli and ciprofloxacin may impact calcium oxalate stone formation in a DM urolithiasis model. Further investigation is required in order to confirm these results and delineate the potential mechanisms by which urinary pathogens and antibiotics may affect calcium-based stone formation.
Source of Funding: AUA Urology Care Foundation Research Scholar Award