Bacteria usually come from the intestine (enterobacteria) with Escherichia coli being the bacteria responsible for most infections. However, a pre-treatment urine culture is always advisable so an antibiotic targeted at the bacteria responsible can be prescribed, preventing complications and antibiotic resistance.

• Being female: A woman’s urethra is shorter, the distance travelled by bacteria to the bladder is therefore also less.
• Menopause: Low oestrogen causes changes in the urinary tract making women more susceptible to infection.
• Urinary tract obstructionKidney stones or an enlarged prostate increase the risk by trapping urine in the bladder.
• Conditions that affect the immune system such as diabetes or pregnancy.
• Using a urinary catheter.

Diagnosis is made on description of symptoms and a urine test.
 
In the Emergency Department we usually perform urinalysis using a urine test strip (Combur-Test) which gives us an immediate result.
 
The most useful values provided by this test are whether leucocytes (inflammatory cells), erythrocytes (blood) or nitrites are present. The first two are very nonspecific values that can also be positive in other conditions. However, a positive result for nitrites is highly specific for the diagnosis of a urine infection, indicating that bacteria capable of converting nitrates (normally present in urine) into nitrites have been identified.
 
A negative nitrite result does not rule out urine infection because there are bacteria that do not have the ability to convert nitrates to nitrites.
 
In all cases urine culture and antibiotic sensitivity are recommended to enable identification of the bacteria causing the infection and the antibiotics to which they are sensitive.

Treatment is given with the antibiotic indicated according to the antibiotic sensitivity.
 
Useful preventative measures are to keep well hydrated with fluids and consume cranberries, making it difficult for bacteria to adhere to the genitourinary tract, and to pass urine after having sex.

An early diagnosis and establishment of the correct antibiotic treatment are important, a delay in the start of treatment can trigger a kidney infection (pyelonephritis), which can result in permanent kidney damage or a generalized infection (sepsis) that may compromise the patient’s life.