Urinary tract infections (UTIs) are the most common type of infection in women, occurring in up to 40% of women in the United States throughout their lifetime. Uncomplicated UTIs are localized to the bladder and can be called cystitis, referring to inflammation of the bladder in reaction to the infection (for this reason, it is also commonly referred to as a “bladder infection”). Complicated UTIs involve infection that spreads past the bladder to the kidneys or other urinary structures and will manifest with more serious symptoms like fever, back pain, and vomiting most commonly, and more commonly occur in people with diabetes, pregnancy, immunosuppression, old age, or abnormalities of the urinary tract. The most common bacteria involved in uncomplicated UTIs is Escherichia coli, followed by Klebsiella.[1]
What is a UTI?
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•Last Updated: May 16, 2025
Urinary tract infections (UTIs) are the most common type of infection in women and affect up to 40% of them in their lifetime; UTI can be classified as uncomplicated (localized to the bladder, known as cystitis), or complicated (involving the kidneys and other structures). The most common bacteria that causes uncomplicated UTIs is Escherichia coli; more severe symptoms occur in complicated cases, particularly in people with certain risk factors.