Gag Therapy for Recurrent Urinary Tract Infection Assessing Comparability to International Nitrofurantoin Gold Standard Study

Inclusion Criteria: 1. Adult female patients (\>18 years) who had at least 3 symptomatic UTI's in the previous year with no adequate curable therapeutic options (e.g. bladder stones) 2. At least one UTI's must be confirmed with a positive culture and antibiogram, further UTI's must be confirmed with a urine sediment with positive nitrite or a positive culture. Exclusion Criteria: 1. Male 2. \< 18 years 3. Pregnant 4. Already on GAG therapy 5. Already on prophylactic antibiotics 6. Started or stopped cranberry/d-mannose therapy or vaginal estrogenic creme in the last two months 7. Had Gentamicin or other antibiotic instillations in the previous 2 months 8. Allergic to \>3 regular used antibiotics in Dutch guidelines (ed. Nitrofurantoin, trimethoprim, Fosfomycin) 9. A urinary fistula 10. Urinary stones 11. Urogenital cancer 12. Bladder Pain Syndrome - Interstitial Cystitis 13. Chronic pelvic pain 14. Had a STD untreated or treated in the previous 2 months 15. A urinary diversion 16. An Indwelling catheter 17. A suprapubic catheter 18. Performing \>1/day self-catheterization 19. A residue after voiding (PVR) of \>200ml 20. Unable (also legal) to give informed consent 21. Recurrent urosepsis 22. Multiresistant bacteria in previous urine cultures 23. Contra-indications and interactions for Nitrofurantoin: severe kidney disfunction (GFR \< 30), lung- or liver problems or neuropathy after previous use of nitrofurantoin, acute porphyria, known G6PD deficiency, use of magnesium trisilicate. 24. Contra-indications and interactions for trimethoprim: severe kidney or liver dysfunction, blood count abnormality, use of vitamin K antagonists, use of folic acid antagonists, use of ace inhibitors 25. Severe lung/respiratory disfunction (reduced lung capacity, lung cancer, fibrosis, COPD) 26. Does not tolerate catheterization