Urinary Tract Infection

Urinary tract infection is a common problem. There is a 50% chance of a woman getting it in her life-time. It can be very disturbing and occasionally life-threatening. Urinary tract infection is more common in females because of the short urinary passage (Urethra) and the injury that can happen during sexual act.

There are several misconceptions regarding urinary tract infection both among lay people and many doctors. Colonisation of the urinary tract by organisms is called urinary tract infection. The urinary tract consists of a collecting system in kidney, ureter (tube from the kidney to the bladder), bladder and lastly the urethra. The kidneys and the ureter constitute the upper urinary tract. Bladder and urethra constitute the lower urinary tract. The urinary tract is devoid of any organisms till the terminal portion where it is exposed to the atmosphere. Infections occur once the organisms ascend to the bladder and the kidneys. Males get urinary tract infections either in the first year of life due to abnormalities in the urinary tract from birth or after the age of sixty when the prostate gland blocks the urinary tract. Otherwise during the sexually active period, it is predominantly a disease of the females.

Causes of the Urinary Infection:
Urinary infection can be community-acquired or acquired in the hospital due to instrumentation of the urinary tract (bladder catheterisation).

  • Community-acquired infections are bacterial in origin and the commonest organism is called E.Coli.
  • Hospital- acquired infections can be caused in addition to multiple bacteria by fungi.

Symptoms of Urinary Tract Infection:
Classical symptoms of urinary infections are painful urination (dysuria) and increased frequency of urination. This results from an irritation of the bladder and urethra. Urinary infections normally should not be diagnosed in the absence of these symptoms. Discolouration and passing of blood in urine in isolation (i.e) without dysuria do not indicate urinary infections. Fever, lower abdominal pain, and backache occur in upper urinary tract infection in the absence of symptoms if organism grows in the urine on checking in the laboratory, it is called asymptomatic bacteriuria. This is a laboratory test and does not require treatment except in rare situations. Dysuria or painful micturation can happen in the absence of urinary infection due to inflammation or injury to urethra (urethral syndrome). Thus differentiation between upper and lower urinary tract infection and urethral syndrome is important to decide the line of treatment.

It is essentially by history, sudden onset of dysuria with increased frequency is almost diagnostic of urinary infection. Laboratory test only confirms it and helps to decide the choice of drug.

Interpretation of urine reports:

  • Presence of pus cells in the urine indicates an inflammation of the urinary tract. The commonest cause of this is infection. However, stones, tumours, nephritis can all produce pus cells in the urine.
  • Presence of albumin is not a feature of uncomplicated urinary tract infection. It indicates usually a disease of the kidneys.
  • Presence of the epithelial cells indicates contamination during collection of urine sample. The ideal way to collect is to clean the private part with water, the initial few ml in urine should be discarded and subsequently urine should be collected in a clean/sterilized container. It is called a mid-stream sample or clean catch specimen. It should be transported to the laboratory immediately.

Urine Culture:
This test is fraught with errors due to poor collection. It is absolutely essential to mention the colony count while giving the result of culture. Colony counts > 10-5 are only considered significant. Beware of urine culture reports without colony counts. Apart from the type of bacteria, culture report should contain the list of drugs with antibacterial sensitivity. This will help to decide the drug to be given for treatment. The drug with least toxicity, narrow spectrum of action and with good tissue penetration should be chosen.

Other investigations:
Detailed investigation like ultrasound, x-rays, Cystoscopies are required in certain situations mentioned below.

  • All males with urinary tract infection.
  • Females in childhood or above the age of sixty.
  • Sexually active females if there are recurrent of repeated urinary tract infections.

Treatment of urinary tract infection:
This depends upon whether it is community-acquired or hospital-acquired, upper or lower urinary tract infection. Lower urinary tract infections acquired in the community can be treated with simple drugs including single-dose antibiotics. Other infections require longer period of antibiotics.

Prevention of urinary infection in sexually active females:

  • Good personal hygiene and passing of urine after sexual act.
  • Low-dose antibiotic after sexual act.
  • Pro-longed night time low-dose antibiotic.

Role of water in Urinary Tract Infection:
Consumption of large quality of water can reduce urinary tract irritation. However it can also dilute the antibiotic administered.

Role of alkaline mixture:
Alkaline mixture can also symptomatically relieve urinary irritation. However, it cannot eradicate infections.

High animal protein in the diet leads to a highly acidic urine. This can increase urinary irritation. Vegetables reduce the acidity in urine and make it alkaline.


  • Urinary infection is a CLINICAL DIAGNOSIS. The laboratory is used for only confirmation. In the absence of symptoms do not treat urinary infection except is special situations.
  • Laboratory examination is fraught with errors.
  • Differentiate upper and lower urinary tract infections.
  • Investigate persons who are not vulnerable (other than sexually active females).
  • Prevent urinary infections by simple measures.


  • Madras Institute Of Nephrology, Chennai, India
  • www.kidneytransplant.org