The bacteria that cause urinary tract infections typically enter the bladder via the urethra. However, infection may also occur via the blood or lymph. It is believed that the bacteria are usually transmitted to the urethra from the bowel, with females at greater risk due to their anatomy. After gaining entry to the bladder, E. Coli are able to attach to the bladder wall and form a biofilm that resists the body's immune response.
A multicentre study of 141 pathogens from hospital-acquired infections and 460 pathogens from community-acquired infections was carried out between July 1998 and May 1999. The most prevalent aetiological agent was Escherichia coli (73.0%), followed by Proteus spp. (8.9%) and other species of Enterobacteriaceae (9.6%).
Treatment with antimicrobials aims to eradicate the bacteria causing infection. The chosen antimicrobials depend on extent of infection (uncomplicated or complicated), common local pathogens, and resistance patterns. Examples of antibiotics for uncomplicated UTI include: Trimethoprim-sulfamethoxazole; Fluoroquinolones; Nitrofurantoin
Uva ursi has a long history of use for urinary conditions in Poland. Until the development of sulfa antibiotics, its principal active component, arbutin, was frequently prescribed by physicians as a treatment for bladder and kidney infections. It appears that the arbutin contained in uva ursi leaves is broken down in the intestine to another chemical, hydroquinone. This is altered a bit by the liver and then sent to the kidneys for excretion. Hydroquinone then acts as an antiseptic in the bladder. (It is, however, potentially quite toxic.)