Urinary Tract Infection (UTI) Causes, Symptoms, Treatment (Medication)

What is a UTI?

UTI is the acronym for urinary tract infection. This refers to an infection of the urethra, bladder, ureter and/or kidney. Most UTI’s are due to bacteria but other microbes may also be responsible although this is rare. The action of the causative microbe results in inflammation of the organ or part of the organ that it has infected leading to a host of symptoms like :

  • pain/burning when urinating (dysuria)
  • frequent urination
  • urging
  • incontinence
  • discharge (foul odor)
  • blood in the urine (hematuria)
  • cloudy urine
  • fever
  • pelvic pain, tenderness

Different terms are used to indicate inflammation due to an infection of certain parts of the urinary tract.

  • Urerthritis ~ urethra
  • Cystitis ~ bladder
  • Ureteritis ~ ureter
  • Pyelonephritis ~ kidney

In men, the prostate gland may also be infected and this is referred to as prostatitis.

It should be noted that these terms may be used for other causes of inflammation. For example : interstitial cystitis is the inflammation of the bladder due to non-infectious causes. Apart from the symptoms of a UTI, a urinalysis will confirm the presence of microorganisms and a culture will help assist with identifying the causative organism.

What Causes UTI’s (Urinary Tract Infections)?

Bacteria colonize the distal part of the urethra even in a healthy person. This does not cause a UTI unless some contributing factor like obstruction or reduced output of urine, trauma to the urinary tract and changes in the composition of urine allows for bacterial spread.

Bacteria cause most urinary tract infections and enter through the urethra. The bacteria multiply in the bladder and can infect the ureters and eventually the kidneys. Bacterial infections that start in the kidneys are more serious as it means that the causative microorganism has reached the kidney through the bloodstream and there is a greater risk of septicemia.

The most common bacterial causes of a UTI include :

  • Escherichia coli (E.coli is the most common cause)
  • Staphylococcus saprophyticus
  • Proteus mirabilis

Fungal infections are more likely to affect the bladder and kidney and often reach the kidney through the bloodstream.  It does sometimes start in the lower urinary tract (urethra and bladder) as a result of the insertion of a catheter when treating other urinary tract conditions.

The most common fungal cause of a UTI is due to the Candida species (spp)  although other species (example : Cryptococcus spp, Aspergillus spp) may also be responsible. Fungal urinary tract infections like renal candidiasis is rare in a healthy person and most cases are seen in immunocompromised patients (HIV/AIDS, uncontrolled diabetes, cancer, chemotherapy).

Other Infections of the Urinary Tract

Many sexually transmitted diseases may cause a UTI including Neiserria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and herpes simplex virus. Schistosomiasis (Schistosoma haematobium) or bilharzia  is an infection with a flatworm (fluke) which lodges in the bladder and causes significant damage to the lining of the bladder.

Signs and Symptoms

Most urinary tract infections are due to bacteria. Although there are various different types of bacteria that can cause urinary tract infections, it is the bacteria from the bowels especially Escherichia coli (E.coli) that are mainly responsible for UTIs. Overall UTIs are more common in women than men largely due to the shorter urethra. This means that the bacteria, or other microorganism can quickly travel up the urethra to lodge in the bladder leading to cystitis. However, in the senior years the risk of UTIs are the same between men and women. UTIs are marked by :

  • Burning pain in the urethra during urination (dysuria)
  • Pain in the middle of the pelvis above the genitalia
  • Frequent urination
  • Urging to urinate
  • Blood in the urine – microscopic or grossly visible
  • Urine has an unpleasant odor.
  • Cloudy urine

However, a large number of urinary tract infections particularly in the elderly are asymptomatic.

UTI Treatment in Women

The approach to treatment changes for complicated and uncomplicated urinary tract infections in women. Most cases are ascending UTIs meaning that it infects the urethra and cystitis and then spreads upwards to the ureter and kidney. In a complicated UTI, the infection has passed the bladder and involves the kidney (pyelonephritis). Phenazopyridine is used for pain, discomfort and spasm of the bladder.

Uncomplicated UTI

First-line treatment used in acute cases includes :

  • Trimethoprim-sulfamethoxazole
  • Nitrofurantoin monohydrate/macrocrystals
  • Fosfomycin

Fosfomycin is not suitable as a first line therapy for pregnant women.

Second-line therapy involves :

  • Ciprofloxacin
  • Levofloxacin
  • Ofloxacin

Complicated UTI

Complicated UTIs can be treated with oral antibiotics if tolerate or intravenous antibiotics may be necessary. Oral antibiotics include :

  • Ciprofloxacin
  • Levofloxacin

Intravenous (IV) antibiotics is necessary for patients who cannot tolerate oral therapy or infection with resistant bacteria.

  • Ciprofloxacin
  • Levofloxacin
  • Ampicillin
  • Piperacillin-tazobactam
  • Doripenem
  • Imipenem-cilastatin
  • Meropenem

Pregnant Women

First line therapy in pregnant women includes the use of :

  • Nitrofurantoin monohydrate/macrocrystals
  • Amoxicillin
  • Amoxicillin-clavulanate
  • Cephalexin
  • Cefuroxime

Fosfomycin is second line treatment in pregnancy.

UTI Treatment of Men

Urinary tract infections in men are always considered as a complicated infection. Phenazopyridine is used for pain relief and bladder spasms.

  • Ciprofloxacin
  • Levofloxacin
  • Ofloxacin
  • Norfloxacin
  • Trimethoprim
  • Trimethoprim-sulfamethoxazole
  • Ampicillin
  • Amoxicillin
  • Gentamicin
  • Ceftriaxone
  • Ceftazidime
  • Tobramycin
  • Erythromycin
  • Vancomycin
  • Doxycycline
  • Ertapenem
  • Aztreonam
  • Nitrofurantoin
  • Rifampin

UTI’s may complicate into infections of other organs :

UTI Treatment in Children

The types of antibiotics used in treating bacterial UTIs in children differs depending on the age of the child.


The following antibiotics are administered intravenously in babies under 8 weeks of age.

  • Ceftriaxone
  • Cefotaxime
  • Ampicillin
  • Gentamicin


The following antibiotics are administered orally in babies between 8 weeks to 2 years.

  • Sulfisoxazole
  • Sulfamethoxazole and trimethoprim
  • Amoxicillin and clavulanic acid
  • Cephalexin
  • Cefixime
  • Cefpodoxime
  • Nitrofurantoin – for lower UTIs


The following antibiotics can also be used in children older than 2 years.

  • Sulfisoxazole
  • Sulfamethoxazole and trimethoprim
  • Amoxicillin and clavulanic acid
  • Cephalexin
  • Cefixime
  • Cefpodoxime
  • Nitrofurantoin – for lower UTIs.

Other measures for relief of symptoms in children like urinary pain includes :

  • Increase fluid intake
  • Acetaminophen (paracetamol) and other NSAIDs
  • Phenazopyridine hydrochloride – short term use for severe and persistent symptoms.

UTI Remedies

There are several simple lifestyle measures that can be implemented to help relieve the symptoms or reduce the frequency of recurrent infections. These remedies cannot replace the use of medication like antibiotics.

  • Drink extra water to help flush out the bacteria.
  • Avoid substances like caffeine, alcohol and citrus juices because this can irritate the bladder.
  • Cranberries have been shown to be helpful in disrupting the attachment of bacteria to the inner lining of the bladder and urethra.
  • Sitting for short periods between 20 to 30 minutes in a warm water tub can be helpful in easing some of the symptoms in children.
  • A heat pad set to a warm, but not hot, setting can be applied to the abdomen to ease some of the UTI symptoms in adults.


  1. Pediatric UTIs. Medscape Reference
  2. UTI Treatment in Males. Medscape Reference
  3. Cystitis in Females. Medscape Reference

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