Hello, There are several risk factors which causes recurrent UTIs like- abnormality of urinary tract, diabetes, incomplete bladder emptying, immune suppression, contraception use. This is caused by same organism or by another organism. So you should first of all go through some investigations like Urine microscopic examination, urine culture & sensitivity to know the exact causative organism and for change of antibiotic, Blood sugar estimation, radionuclide imaging to know any abnormality. Some of preventive measures are- continue the antibiotic until test result obtained, post coital voiding and antibiotic prophylaxis, drink plenty of water each day, maintain local hygiene as much as possible. Consult a physician and then follow the instruction. Take care bye.