A bacteria or virus can be what causes urethritis. A common bacterium that causes urinary tract infections, E. coli, can also lead to urethritis. E. coli is usually found in the colon and can easily spread to the urethra in women, causing urethritis.
Sexually transmitted microorganisms, Chlamydia trachomatis and Neisseria gonorrhea, can cause urethritis in both men and women. In men, the urethritis can include the testicles and the epididymis. In sexually transmitted diseases, both partners must be treated.
Treatment of urethritis depends on the cause. For E. coli infections, antibiotics such as trimethoprim, sulfamethoxazole, amoxicillin, ampicillin and ofloxacin are used. For bacterial sexually transmitted diseases, the most common treatment options include tetracycline, doxycycline or trimethoprim/sulfamethoxazole medications, according to the National Kidney and Urologic Diseases Information Clearinghouse.