Corresponds to the presence of bacteria in any part of the urinary system (kidneys, ureters and bladder). Depending on the location, the infection is given different names. In the case of the kidney it is called pyelonephritis, the bladder cystitis and the urethra is called urethritis.

They are one of the most common infections. In general, microorganisms reach the urinary system from the outside, through the urethra or, more rarely, from the blood and settling in the kidneys. Bacteria that reach the urinary tract, as a rule, are quickly removed before causing infection by the elimination of urine and the body’s defenses. When this does not happen, the symptoms of infection become evident.

They are more common in women, given the closer proximity of the female urethra to the anus and the vagina and the fact that it is a much shorter urethra than the male, which allows microorganisms to reach the bladder more easily.

Children, particularly males up to one year old, also have a high prevalence of infection at the renal level, due to the presence of urethral vesic reflux.


The main symptoms that urinary infection causes are:

  • Burning or painful urination
  • Occurrence of frequent and small urination
  • Urgent and frequent urge to urinate
  • Foul-smelling urine
  • Changes in its color
  • Difficulty starting urination
  • Elimination of blood in the urine
  • Pain in the lower abdomen
  • Fever
  • Chills
  • Backache
  • Nausea
  • Vomiting

Most have no significant severity. Except for those involving the kidneys and requiring special care. Kidney damage from a urinary infection can cause kidney scarring, high blood pressure or even kidney failure.


The most common causes of urinary tract infection are:

  • Pregnancy
  • Diabetes
  • Urinary obstruction
  • Inadequate hygiene habits
  • Insertion of foreign objects
  • Menstrual period
  • Neurological diseases
  • Sexually transmitted diseases

The presence of abnormalities in the urinary tract also tends to increase your risk. The same goes for institutionalized patients or those submitted to algalization.

The responsible microorganisms vary depending on where the infection is acquired. When it occurs in an outpatient, the most common agent is Escherichia coli (about 80% of cases) and some staphylococci. In hospitalized or institutionalized patients, these bacteria may also be responsible, but others appear more aggressive and, therefore, more complex treatment. These patients also have urinary infections caused by fungi.


Often, with a first episode of urinary infection in a woman, treatment is immediately instituted without resorting to a laboratory diagnosis.

In cases of recurrent infections, in children or in hospitalized patients, it is important to assess which microorganism is responsible and try to identify which situations may be the basis of the infection.

Thus, in addition to medical evaluation, laboratory diagnosis is important in allowing the sample to be evaluated, its physical and chemical composition, the presence of microorganisms and, if they are present, their susceptibility to different antibiotics. This aspect is relevant to be able to select the most appropriate antibiotic for each case.

In order for this diagnosis to be effective, it is essential that the urine collection be carried out according to very strict rules, which are different in men, women, children and patients with pain.

In the case of recurrent urinary tract infections, more in-depth assessments may be necessary, using ultrasound, tomography or magnetic resonance imaging, among other diagnostic techniques.


In addition to treatment with the most appropriate antibiotic, it is important to take some extra precautions:

  • Increase fluid intake
  • General care of intimate hygiene
  • Correct any anatomical changes that may be responsible for infections
  • Do not delay urination (this resistance increases the risk of infection because it allows urine to stay longer inside the bladder)

The treatment of urinary infection with antibiotics should only be started after the bacterium has been identified by the laboratory. However, in daily clinical practice, the procedure is different and, almost always, the patient starts therapy with an antibiotic even without knowing the results of the tests. 

In the case of urinary tract infection during pregnancy, the selection of the antibiotic must be properly considered, since some are contraindicated during pregnancy.

In men, they are often associated with kidney stones or an enlarged prostate, which means that both research and treatment must be guided in a different way.


There are several measures that can reduce the risk of urinary infections:

  • Drink lots of water and urinate frequently
  • Avoid liquids like alcohol and caffeine that can irritate the bladder
  • Urinating right after intercourse
  • Wipe from front to back after urinating and evacuating to avoid contamination from the rectum
  • Keep the genital area clean
  • Prefer showers over baths
  • Avoid using oils
  • Sanitary pads or menstrual cups are preferable to tampons
  • Avoid using diaphragms or spermicides as contraceptive methods
  • Avoid using perfumed products in the genital area
  • Wear cotton underwear and loose clothing to keep the area around the urethra dry