Urinary tract infection (UTI)

What do you mean by urinary tract infection (UTI)?

Urinary tract infection (UTI) is the infection of any part of the urinary system which may include kidneys, ureters, urinary bladder or urethra. Amongst these, the infection of the urinary bladder, the structure where the urine gets collected before releasing out is the commonest type of UTI. This is especially common in females where it is said to develop in about 50% women at least once in their lifetime.

The infection of the kidneys, called pyelonephritis is rare but is a much more serious problem.

The UTI is usually caused by bacteria that typically enters through the urethra and starts multiplying in the urinary bladder. The commonest bacteria to cause UTI is E.coli which is found in the gut, which gets its access due to close proximity of the anus to the urethra, especially in women.

UTI is not mere presence of bacteria or microorganism in the urine. Many a times bacteria can be seen in urine in a person with no symptoms which doesn’t indicate urinary tract infection. When the person develop symptoms or inflammation of urinary tract along with the presence of microrganism in the urine, it is said to be urinary tract infection.

How common is urinary tract infection (UTI)?

Urinary tract infection (UTI) is one of the most common bacterial infections in females, seen developing in about 50% of women at least once in a lifetime. It is less common in males developing in about 8% men. Amongst females about 27% women are found to develop recurrent UTI within 6 months.

What causes UTI ?

The UTI is caused by micro-organisms that usually enters from urethra and ascends upwards into bladder and sometimes to kidneys. Rarely, the UTI develops from infection in the blood which is more often seen in immunocompromised people. The microorganisms that causes UTI are as follows:

Bacteria: comprises most of the cases of UTI. The E.coli is the commonest bacteria to cause UTI accounting for 85% cases. Other bacterias that causes UTI are Proteus, Klebsiella, Enterococcus faecalis etc.

Fungus: is a less common cause, accounting for about 7% of cases. In recent decades, it has shown increase in number of cases with risk factors given below. The commonest fungus to cause UTI is Candida albicans accounting for 50% to 70% cases. Other fungi to cause UTI can be Cryptococcus neoformans, Aspergillus species and others.

Virus: UTI is rarely caused by a virus. If it is seen, it is more often seen in immunocompromised people such as organ transplant recipients. It is usually caused by BK virus,cytomegalovirus or adenovirus.

What are the types of urinary tract infections (UTI)?

The UTI is typically classified into two types on the basis of symptoms and prognosis

1. Lower UTI (cystitis) involving bladder and urethra

2. Upper UTI (pyelonephritis) involving kidneys

The lower UTI is much more common than upper UTI. The upper UTI usually occurs when the lower urinary tract infection ascends upwards to involve the kidneys. Most of the time the infection remains restricted to the lower urinary tract. Less often it ascend upwards or spreads from blood to the kidneys.

What are the complications of urinary tract infection (UTI)?

The urinary tract infection may lead to the following conditions:

• Recurrent UTI: where a woman develops more than 1 episode of UTI within six-months period or more than 3 episodes within a year.

• Stricture in the urethra: urethra in men may develop narrowing due to recurrent urethritis leading to obstruction in the passage of urine.

• Kidney damage: due to untreated acute or chronic kidney infection (pyelonephritis).

• Premature birth: UTI in pregnant women may increase the risk of delivering premature babies.

• Sepsis: UTI, especially in susceptible individuals may lead to sepsis. Sepsis is a life-threatening condition where the body shows overwhelming response to the infection which in turn damages multiple organs of the body.