Hello dear Understand your concern. Yes unprotected anal sex has high risk of UTI. Anal canal contains lots of bacteria, after anal sex there is contact between genital tract and again unprotected vaginal intercourse lead to high chance of urinary tract infection. E. coli, Staphylococcus saprophyticus (10 to 15 percent). Enterococcus, Klebsiella, Enterobacter, and Proteus are main pathogens for UTI Some time infection can be detected if it is in incubation period. If problem persists you should both check for STDs. Following are the risks factor for UTI: Frequent intercourse, use of a diaphragm and/or spermicide, obesity, Urinary incontinence unprotected vaginal intercourse with a partner unprotected anal sex Poor hygiene before and after sex. Following are advice for you. - drinking plenty of fluids and not delaying urinating. - advised to wipe from front to back to prevent bacteria from entering the urethra, and to cleanse their genital area before and after sex - Drink fresh cranberry and orange juice - Avoid anal sex if possible - Use safer sex practice-use condoms and lubricants Treatment are below 1. three day course of trimethoprim/sulfamethoxazole (TMPSMX; Bactrim, Septra) is the current standard therapy, 2. with three days of trimethoprim or a fluoroquinolone (i.e., ofloxacin, norfloxacin [Noroxin], or ciprofloxacin [Cipro]) being equally effective. 3. Fluoroquinolones and nitrofurantoin become better options in your case for TMP-SMX resistance increases. 4.If oral drug is not possible, take ceftazidime parentrally. You should shift to oral therapy with in 72 hr as you able to tolerate oral drugs. Follow up urine culture after 14 days to confirm the eradication of bacteria. Tablet Paracetamol 500 mg thrre times a day if fever is present. Tablet cetrizine 4 mg once daily Hope this advice help you.. Thank you. Get well soon.