UTI stands for urinary tract infection, an infection that can develop in any part of your urinary system: the kidneys, ureters (the tubes connecting kidneys to the bladder), bladder, or urethra. Most UTIs affect the lower tract, meaning the bladder and urethra. Roughly 50 to 60% of women will have at least one UTI during their lifetime, making it one of the most common infections worldwide.
What Causes a UTI
UTIs happen when bacteria enter the urinary tract and multiply. The overwhelming majority of cases are caused by E. coli, a bacterium that normally lives in the intestines. E. coli is responsible for up to 90% of simple, community-acquired UTIs. Other bacteria can cause them too, but E. coli dominates.
The infection typically starts when bacteria travel from the skin around the genitals or anus into the urethra. From there, they can move upward into the bladder. If left untreated, the bacteria can continue climbing to the kidneys, which is a more serious problem.
Why Women Get UTIs More Often
Women develop UTIs far more frequently than men, largely because of anatomy. The female urethra is much shorter than the male urethra, so bacteria have a shorter distance to travel before reaching the bladder. The urethral opening is also closer to the anus, where E. coli naturally lives.
Beyond anatomy, the biggest risk factors for younger women are sexual intercourse and the use of spermicidal contraceptives. In older women, declining estrogen levels change the balance of protective bacteria in the vaginal area, raising susceptibility. Other risk factors across age groups include urinary tract obstructions (like kidney stones), catheter use, and a weakened immune system. Men can get UTIs too, though it’s less common and often involves the prostate.
Common Symptoms
A bladder infection, the most typical type of UTI, produces a recognizable set of symptoms:
- Pain or burning during urination
- Needing to urinate frequently, sometimes every few minutes
- Feeling like you need to go even when your bladder is empty
- Cloudy or bloody urine
- Pressure or cramping in the lower abdomen or groin
If the infection spreads to the kidneys, symptoms escalate. You may develop fever, chills, flank pain (pain in your side or lower back), nausea, or vomiting. In older adults, a UTI can sometimes cause sudden confusion or changes in mental clarity without the classic urinary symptoms, which makes it easy to miss.
How UTIs Are Diagnosed
Diagnosis usually starts with a urine sample. The lab checks for two key markers: nitrites and white blood cells. Many UTI-causing bacteria convert a natural chemical in urine called nitrates into nitrites, so finding nitrites in your sample is a strong indicator of infection. White blood cells signal that your immune system is fighting something off. When both show up together, a UTI is very likely.
At-home UTI test strips work the same way, checking for nitrites and white blood cells. They can give you a quick read, but a healthcare provider may also order a urine culture. This identifies the specific bacteria involved and which antibiotics will work against it, which is especially useful if you get recurring infections.
Treatment and What to Expect
Antibiotics are the standard treatment for UTIs. For a straightforward bladder infection in women, treatment is typically short: some antibiotics require just a single dose, while others are taken for three to five days. Most people start feeling better within a day or two of starting medication, though finishing the full course matters to clear the infection completely.
Men with UTIs generally need a longer course of antibiotics, at least seven days, because the infection may involve the prostate. Your provider will choose the antibiotic based on local resistance patterns, since some bacteria in certain regions have developed resistance to commonly used drugs.
For mild symptoms, drinking extra water and using over-the-counter pain relief can help with comfort while you wait for the antibiotic to kick in. The burning and urgency are usually the first symptoms to resolve.
What Happens If a UTI Goes Untreated
A bladder infection that isn’t treated can travel upward to the kidneys, causing a kidney infection (pyelonephritis). This is a significantly more serious condition. Symptoms include high fever, chills, severe flank pain, and rapid heart rate. Kidney infections require stronger antibiotics and sometimes hospitalization.
In the worst cases, the infection can enter the bloodstream and progress to sepsis, a life-threatening emergency. This is more likely in people who have obstructions in their urinary tract, weakened immune systems, or who delay treatment for an extended period. Bladder symptoms that persist beyond seven days, or any combination of fever and flank pain, warrant prompt medical attention.
Lowering Your Risk of Recurrence
For people prone to repeat UTIs, one of the simplest and best-supported prevention strategies is drinking more water. A 12-month clinical trial found that women who added an extra 1.5 liters of water (about six extra cups) to their daily intake significantly reduced their rate of recurrent infections. The logic is straightforward: more fluid means more frequent urination, which flushes bacteria out of the bladder before they can multiply.
Other commonly recommended habits include urinating shortly after sexual intercourse, wiping front to back after using the bathroom, and avoiding spermicidal products if you’re prone to infections. None of these carry any risk, and while the evidence is stronger for some than others, they’re practical steps worth incorporating if UTIs are a recurring problem for you.