Welcome to HCM,
UTI is sometimes tricky to treat as notorious and resistant organism cause the infection. The most common organisms are E.Coli and it is advisable to get a culture and sensitivity testing and take proper antibiotics for sufficiently long duration to eradicate infection.
Simple measures like taking plenty of fluid and water.
In some cases re infection can occur due to various causes like obstruction to urinary tract
by stricture or stone in the tract,and not ignore personal hygiene and short length of urethra in females.
Please see a good Urologist
and get urine culture and sensitivity and Ultrasonography
and if required a cystoscopy and treatment accordingly.
Rarely atypical infection
may be cause?
If you follow proper treatment you will be cured soon.
Please take care