Escherichia coli urinary tract infections: Diagnosis and treatment

Manura Nanayakkara By Manura Nanayakkara, 26th Aug 2010 | Follow this author | RSS Feed | Short URL
Posted in Wikinut>Health>General Health>Diseases & Infections

Escherichia coli (E.coli) is a type of bacteria that causes more than 80% of urinary tract infections in adults. It is a mild community acquired infection (Not hospital acquired). It’s common in people, with normal urinary tracts (without catheter or urinary stones).

Escherichia coli urinary tract infections: Diagnosis and treatment

How to Diagnose

Patients with infection in the bladder and urethra usually complain painful urination, increased urinary frequency, and lower abdominal pain. Urine often becomes grossly cloudy and malodorous and is bloody in approximately 30% of patients.

In pyelonephritis (infection in kidney and surrounding areas), symptoms generally develop rapidly over a few hours or a day, and include fever, shaking chills, nausea, vomiting, abdominal pain, and diarrhea with or without symptoms of bladder infection.

Urine tests

For best results patients should take an early morning mid stream urine sample to the lab. Results of these tests may become useless, if the patient has taken antibiotics prior to getting the sample.

Urine full report (UFR) or urinary microscopy

In an E.coli urinary tract infection, UFR will have increased pus cells and red cells. But pus cells are more and they are dead neutrophils. It indicates active infection in urinary tract.

In a symptomatic urinary tract infection, E.coli bacteria can be seen in high power microscopes with specific stains (specific coloring to identify the organism). The detection of bacteria by urinary microscopy thus constitutes firm evidence of infection, but the absence of microscopically detectable bacteria does not rule out a urinary tract infection.

Another test with less sensitivity than urinary microscopy is “dipstick” method. It detects an enzyme called leukocyte elastase. This indicates a high leukocyte activity in infected urinary tract.

Urine culture and antibiotic sensitivity test (ABST): - It allows E.coli to grow in a lab, count the number of colonies present and then testing various antibiotics for sensitivity on them. More than 10^5 bacteria, of a single species, per milliliter, of urine are necessary to diagnose a urinary tract infection, and identify the offending organism.

Ultra sounds scan, and X – Ray with contrast will detect any structural abnormalities or stones in the urinary tract.

Sometimes urinary cystoscopy (endoscopic examination of the bladder and urethra) is needed to detect structural abnormalities.

How to Treat

Milder forms of urinary tract infections with E.coli can be treated with common antibiotics. Many doctors have advocated single-dose treatment for milder E.coli infections. But it is usually necessary to treat, at least for three days to prevent recurrence.

Antibiotic sensitivity changes over time and place. So urine culture and ABST is necessary before treating a complicated infection. Usually antibiotics are given, more than a week in a complicated urinary tract infection.

Examples of common oral antibiotics that are used in urinary tract infections are Cipro, Zinnat, furadentin, tavanic, and bactrim.

Dr. Manura Nanayakkara is a Medical doctor working in Sri Lankan hospital.
All content within this article is provided for information only and should not be treated as a substitute for the medical advice given by a doctor or any other health care professional. Author of this article is not responsible or liable for any diagnosis made by a user based on the content of this article. In addition, this author is not liable or responsible for the contents of any external internet sites listed and does not endorse commercial product or service mentioned or advertised.


Cloudy Urine, Ecoli, Infection, Urine Infection, Uti

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author avatar Manura Nanayakkara
I am a Medical doctor working in Sri lanka. My other writing sites,

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