Healthy Living

E. coli and Urinary Tract Infections

E. Coli and Urinary Tract Infection (UTI): Symptoms, Treatment, Causes & Types

What is a urinary tract infection?

The main function of the urinary system is to get rid of waste, maintain the body’s water balance, and regulate electrolytes. Its function starts with the kidneys, the organ that filter blood to produce urine, which is composed of extra fluid and wastes. Before leaving the body, urine travels through two thin tubes called ureters to reach the bladder, which stores urine. The bladder is emptied when it is time to urinate. Urine flows out of the body through When it is time to urinate, the bladder empties and urine flows out of the body through a tube called urethra.

As you might expect, a urinary tract infection (UTI) is an infection that affects the urinary system, which includes the kidneys, urinary bladder, ureters, and urethra. A urinary tract infection usually happens when some of the bacteria that come from intestines through bowel movements come out of the body and get inside the urethra and into the bladder, wherein it causes an infection. If bacteria continue to spread, they can reach the ureters and climb up to the kidneys, and cause a kidney infection called pyelonephritis, which can be life-threatening. 

The common symptoms of a urinary tract infection are:

  • Painful or burning sensation when passing urine
  • Sudden urge to pass urine
  • Frequently passing small amounts of urine 
  • Pressure or pain in the lower abdomen
  • Hematuria (blood in urine)
  • Cloudy urine
  • Unusual urine odor

What is E. coli?

E. coli is a bacterium that normally lives in the bowels of healthy people and animals. Most E. coli bacteria do not cause any harm. They are even part of the human gastrointestinal tract. However, there are E. coli strains that can cause disease, which can either be diarrhea or any disease outside of the GI tract. 

Escherichia coli or better known as E. coli, is the bacterium responsible for over 80 percent of common UTI cases. Other bacteria can also cause UTI, and they include Pseudomonas aeruginosa, Staphylococcus saprophyticus, and Klebsiella pneumoniae. When E. coli finds its way to the lungs, it can cause respiratory problems. Few cases can lead to pneumonia. 

According to one research, E. coli is the causative agent of around 20-30 percent cases of neonatal meningitis. Neonatal meningitis is a life-threatening bacterial infection that affects the meninges, which surround and envelop the brain and spinal cord. 

E. coli is also widely known for its involvement in intestinal infections and food poisoning outbreaks.

E. coli and Urinary Tract Infections

Every year, there have been around more than 7-8 million cases of UTI alone in the United States as per one of the reports of CDC. Urinary tract infections are more commonly seen in women than men. In fact, women are four times more prone to getting a urinary tract infection than men. Over 50 percent of women get urinary tract infections at least once in their lifetime. 

One of the main reasons is that women have a short urethra, thereby making it possibly easier for E.coli bacteria as well as any other bacteria to easily enter the urinary bladder. In addition, the opening of the urethra in women is near the anus, where bacteria from the bowels are excreted.

Both men and women may develop urinary tract infections if they have the following factors:

  • Kidney stones or any urinary tract obstruction
  • An impaired or weak immune system
  • An indwelling catheter
  • Spinal cord injury or any other form of nerve damage around the bladder, which prevents complete emptying of the bladder and allowing bacteria to grow and multiply
  • Enlarged prostate in men
  • Diaphragm use in women
  • Spermicidal condom use in sexually active women

Types of Urinary Tract Infections and Their Symptoms

1. Acute pyelonephritis (affects the kidneys)

The symptoms of acute pyelonephritis usually show within 48 hours of infection. Its common symptoms are: 

  • High fever ( more than 102 degrees Fahrenheit or 38.9 degrees Celsius)
  • Chills
  • Nausea and vomiting
  • Abdominal pain
  • Pain in the back, groin, or side
  • Fatigue
  • Mental confusion
  • Painful or burning sensation when urinating
  • Cloudy urine
  • Pyuria (pus in urine)
  • Hematuria (blood in urine) 
  • Urinary urgency and frequency
  • Distinct fishy smell in urine

2. Cystitis (affects the bladder)

  • Low-grade fever
  • Persistent urge to pass urine
  • Frequent urination but only in small amounts 
  • Painful or burning sensation when urinating
  • Cloudy urine
  • Hematuria (blood in urine)
  • Pelvic pain or discomfort
  • Lower abdominal (pelvic) pressure
  • Abnormal urine odor (strong-smelling)

3. Urethritis (affects the urethra)

  • Difficult or painful urination (dysuria)
  • Urinary urgency and frequency

Urinary Tract Infections and Antibiotic-Resistant E. coli 

The standard treatment for most urinary tract infections is antibiotics. However, some E. coli strains are resistant to most antibiotic drugs. These strains are called extended-spectrum beta-lactamase (ESBL)-producing E. coli. Researchers found that UTIs caused by E. coli, which are resistant to ciprofloxacin, increased from 3-17 percent in 2000 up to 2010. Moreover, E. coli strains that are resistant to trimethoprim/sulfamethoxazole also increased from 18-24 percent.

UTI Complications 

When lower urinary tract infections are properly treated on time, complications rarely occur. However, when UTIs are left untreated, serious complications may happen.

Complications from a urinary tract infection may include:

  • Recurrent UTIs (women who have more than two UTIs within a year)
  • Kidney damage (permanent)
  • Delivering preterm infants along with low birth weight
  • Urethral stricture (narrowing) in males
  • Sepsis (a life-threatening complication caused by the body’s response to certain infections)


There are multiple tests that can be used to diagnose urinary tract infections:

  • Urine test: The doctor may ask you to collect a urine sample for a urinalysis. The test involves checking the presence and amount of red blood cells (RBCs), white blood cells (WBCs), or bacteria. Before collecting a urine sample, you will be given specific instructions to avoid any contamination. A midstream clean-catch urine is usually the preferred sample for routine urinalysis. 
  • Urine culture: A urine culture may be ordered by your doctor depending on your urine test results. A urine culture involves growing bacteria in the laboratory. This test helps the doctor in identifying what type of bacteria is causing your UTI, and the type of antibiotic that would be most effective for your condition. 
  • Cystoscopy: Doctors may recommend cystoscopy to individuals with recurrent urinary tract infections. This procedure involves the use of a cystoscope to visualize your bladder on the inside. A cystoscope (a thin tube with lens) is inserted into the urethra and through the bladder. 
  • Images of the urinary tract: If the doctor suspects an abnormality in the urinary system, imaging scans such as an ultrasound, CT scan, or MRI may be performed. A contrast dye may also be used to highlight urinary system structures. 


The first line of treatment for UTIs is usually antibiotics. However, antibiotic treatment also depends on your overall health status and the type of bacteria that cause the infection. 

When it comes to simple urinary tract infections, the following antibiotics are usually prescribed:

  • Ceftriaxone
  • Cephalexin (Keflex)
  • Fosfomycin (Monurol)
  • Nitrofurantoin (Macrodantin)
  • Trimethoprim/sulfamethoxazole (Bactrim)

For individuals who have an uncomplicated UTI, doctors may recommend a shorter antibiotic course (1-3 days of antibiotic therapy). However, a short course of antibiotic treatment also depends on your medical history and specific symptoms.

Analgesics or pain relievers may also be prescribed to relieve pain and burning sensations when passing urine. However, such pain usually goes away after taking the appropriate antibiotic for your infection.