Urinary infection is defined as infection in the urine. Bacteria do not normally live in the urinary system and urine is sterile though urine is a very good culture medium. However, under normal circumstances bacteria do not get an opportunity to grow as urine is completely flushed out during the process of urination and the mucosal covering of the urinary bladder have local defense mechanisms against bacteria. When the urine stagnates or when the protective mechanisms fail, infection occurs. When the infection is confined to the urinary bladder it is called cystitis. This is the most frequent form of urinary infection. Occasionally, infection can involve the kidney and this condition is called pyelonephritis. This is a serious condition, which is associated with severe loin pain and high-grade fever.
Urinary infections occur much more frequently in women than in men. This increased predilection among women is mainly due to two reasons. In women, opening of the urinary passage is close to the anus. Thus, bacteria from the anus can find its way to the urinary system very easily. The vast majority of urinary infections are caused by a bacterium called Escherichia coli (E. coli), which is one of the most common organisms found in stool. Migration of bacteria from the opening of the urinary passage into the urinary bladder can be facilitated by sexual intercourse also. Use of spermicidal gelly also predisposes to urinary infections.
If adequate toilet facilities are not available, women in particular may be forced to hold the urine in the bladder for a long time. This situation is commonly observed while travelling. Prolonged stasis of urine and stretching of the bladder mucosa may lead to bacterial growth and subsequently urinary infection.
Urinary infection is generally uncommon in men and even one episode of infection should be investigated for the causes. Structural abnormality of the urinary system and uncontrolled diabetes may predispose men to develop urinary infection. Structural abnormalities include obstruction to the passage of urine flow, backflow of urine into the kidney (a condition called vesicoureteric reflux) and kidney stones.
Symptoms
If the infection is confined to the bladder (Cystitis) patient will experience a burning sensation while passing urine and an urge to pass urine frequently. Occasionally urine may become blood stained and patient may feel pain and discomfort in the lower abdomen. Infection of the kidney is a far more serious condition, which is associated with high- grade fever and pain in the loin on the side of the affected kidney.
Diagnosis
Urinary infection is can be diagnosed based on the symptoms alone. Fever is not a usual feature of cystitis. Loin pain or flank pain will suggest infection of the kidney. If a patient is complaining of high grade fever with chills associated with loin pain one can be certain that he has acute pyelonephritis (infection of the kidney). Urine examination under microscope will show white blood cells. Urine culture should be done in case of recurrent infection or persistent infection. Proper urine sample collection is important for culture and what is recommended is the urine midstream sample.
If the sample is not collected by the correct method, report will be erroneous and interpretation will be difficult. Passing urine into the toilet until it is ‘half-done’ and then bringing a sterile container into the stream and collecting a small volume of urine can collect midstream urine. In men, the foreskin of the penis, if present, should be retracted.
Treatment
Acute cystitis in young healthy adult women doe not produces any long-term complications. Thus, the significance of cystitis in the non-pregnant woman, even if untreated, appears to be limited primarily to the discomfort of symptoms caused by the infection. Treatment may play an important role in reducing the likelihood of progression to pyelonephritis.
Several antibiotics are effective in treating urinary infection. Antibiotic treatment should be based on of the antibiotic sensitivity profile of the usual bacteria causing urinary infections in the community. Flouroquinolones (Ciprofloxacin, Ofloxacin etc) is a group of antibiotics that is effective against a variety of bacteria causing urinary infection. For an episode of acute cystitis, seven days course of antibiotic should be sufficient. Infection of the kidney requires intravenous antibiotics and longer duration of treatment.

Recurrent urinary infections -In some patients, urinary infections can be recurrent or persistent.
Children-Recurrent urinary infection in children can occur due to structural abnormalities of the urinary tract. Vesicoureteric reflux is a condition characterized by backflow of urine from the urinary bladder into the ureter and kidney. It is important to identify this condition and take corrective measures as uncorrected reflux may lead to kidney failure in the long run. Other structural abnormalities of urinary tract also may lead to infections.
Adults
->Uncontrolled diabetes- this leads to reduction in the immunity and facilitates the bacteria to grow
->Urinary stones can function as foci of infection which might be difficult to eradicate
->Enlarged prostate gland may sometimes to retention of some quantity of urine in the bladder after an act of urination. Since urine is a very good culture medium bacteria may tend to grow.
->Poor perinea hygiene may lead to infrequent urinary infections in women
->Failure of the foreskin to retract could be a cause in men.
Preventive strategies
A number of strategies have been recommended to prevent recurrent urinary infections.
1. Increase the fluid intake: Liberal fluid intake and frequent passing of urine may reduce the frequency of urinary infection.
2. Maintenance of good perineal hygiene (external genitalia and area around the anus). When anus is washed after defaecation (passing motion) care should be taken not to contaminate the area around urethra.
3. Women with frequent episodes of urinary infections should be encouraged to pass urine before and after sexual intercourse.
4. Not to hold urine without passing for a long time. During travel it is important to stop at regular intervals at places where toilet facilities are available. It is also important to have clean toilets in the places of work, schools and colleges.
5. Correction of the structural abnormalities of the urinary tract such as resection of the prostate, removal of stones and correction reflux should be considered wherever possible.
6. In diabetic patients good blood sugar control is also essential to prevent recurrent urinary infections.
7. Patients with recurrent infection may be put on a regular course of antibiotic. (Prophylaxis). This has been advocated for women who experience two or more symptomatic infections within six months or three or more over 12 months. The choice of antibiotic should be based upon the antibiotic sensitivity patterns of the different bacteria causing the patient’s previous infections and any history of drug allergies. Before any prophylaxis regimen is initiated, eradication of a previous urinary infection must be assured by obtaining a negative urine culture one to two weeks after treatment.