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Urinary Tract Infections (UTIs) and Proteus Mirabilis Bacteria

Linda Crampton is an experienced teacher with a first-class honors degree in biology. She writes about the scientific basis of disease.

Proteus mirabilis and other bacteria live in the large intestine, which consists of the colon and the rectum.

Proteus mirabilis and other bacteria live in the large intestine, which consists of the colon and the rectum.

Proteus mirabilis and UTIs

Proteus mirabilis is a rod-shaped bacterium that lives in the large intestine of many people. It's often harmless and forms a normal part of the gut flora, which is the often useful community of microbes that shares our intestinal tract with us. Unfortunately, under certain conditions the bacterium may escape from the intestine and cause a urinary tract infection.

Bacteria are routinely shed in the feces. The feces leaves the intestine through the anus. In women, bacteria may pass from the anus to the nearby urethral opening, which leads to the urinary bladder. Once the microbes enter the urethra, they may cause a urinary tract infection, or UTI. Men may develop UTIs as well, though the disorder is less common in males than in females.

Proteus infections are commonly associated with the formation of "stones." The bacterium causes solid crystals to form in urine. Crystals join together to make the stones. Small stones may leave the body on their own. Large ones may become trapped in the urinary tract and obstruct urine flow. They may also be very painful.

The urinary system or tract and nearby blood vessels: 2 = kidney, 3 = renal pelvis, 4 = ureter, 5 = urinary bladder, 6 = urethra

The urinary system or tract and nearby blood vessels: 2 = kidney, 3 = renal pelvis, 4 = ureter, 5 = urinary bladder, 6 = urethra

Structure and Function of the Urinary System

We have a kidney, a renal pelvis, and a ureter on each side of our body (at the back of the abdomen). We have only one urinary bladder and urethra, which collect and transport urine from each kidney.



Produces urine by filtering blood and then changing the filtrate's composition by adding and removing substances

Each kidney contains around a million tiny filtering tubes called nephrons.

Renal pelvis

Drains urine from the kidneys

The renal pelvis is also called the pyelum.


Transports urine from the renal pelvis to the urinary bladder


Urinary bladder

Stores urine temporarily and then sends it to the urethra

Stretch receptors in the bladder lining "tell" the brain that the bladder is full.


Transports urine from the urinary bladder to the outside world

In a male, the urethra also transports sperm, though not at the same time as urine.


Someone who is concerned about experiencing a UTI or who suspects that they may have one or that someone that they care for may have one should contact their doctor for advice. The following information is given for general interest.

Causes of UTIs and Possible Prevention Steps

In women, the anus is behind and close to the urethral opening. It's quite easy for bacteria to move from the anus to the urethra, which is one reason why hygiene and careful toilet habits are important. Health experts recommend that women wipe from front to back after defecation to reduce the chance of bacterial entry into the urethra. Bacteria can also enter the urethra from the opening to the reproductive tract, which is located between the anus and the urethral opening.

Women have a far higher incidence of UTIs than men, not only because of the location of their urethral opening but also because their urethra is shorter. A female's urethra is about one and a half inches in length while a male's is about eight inches long. In a female, the bacteria don't have far to travel to reach the urinary bladder and the rest of the urinary tract.

If some bacterial cells do manage to enter the urethra, the flow of urine may be able to flush them away. Urinating when necessary instead of retaining urine is one method used to reduce the chance of a UTI, as is drinking an adequate amount of water. Infections may develop if a large number of bacteria enter the urinary tract. In addition, people with structural abnormalities in the tract that tend to trap fluid are more likely to develop a UTI. In men, an enlarged prostate gland may exert pressure on the urinary tract and prevent adequate fluid flow, increasing the risk of an infection.

These are white blood cells in the urine of someone suffering from a urinary tract infection. The cells are part of the immune system.

These are white blood cells in the urine of someone suffering from a urinary tract infection. The cells are part of the immune system.

Catheters and Urinary Tract Infections

People who have a catheter in the urethra have an increased risk of a UTI. A catheter is a medical device that drains urine from the body. It's a flexible tube that is placed in the urethra, positioned over the urethral opening, or connected to the bladder to drain urine from the body. The urine enters a drainage bag. The catheter may be inserted temporarily or may be left in place (an indwelling catheter).

A catheter may be used in situations where it's difficult for a person to urinate normally. Two of these conditions are urinary incontinence and urinary retention. In urinary incontinence, a person is unable to stop the release of urine from the bladder. In urinary retention, a person finds it difficult to release urine. A catheter is also used when there is spinal cord damage which prevents the normal process of urination or when a person is temporarily incapacitated in hospital.

Catheters are very useful devices. Unfortunately, the surface of a catheter may become coated with a film of bacteria that is hard to remove and becomes a continuous source of infection.

Anyone with symptoms that might indicate the presence of a UTI should visit a doctor. An untreated infection may have serious consequences. These may include kidney damage or failure. They may also include an infection in the bloodstream that causes widespread inflammation in the body, a condition known as sepsis.

Possible Symptoms of a Urinary Tract Infection

A person may have no symptoms of a urinary tract infection. However, there may be unpleasant symptoms, such as one or more of the following:

  • a strong and frequent urge to urinate
  • a burning pain during urination
  • pain or pressure in the lower abdomen
  • cloudy urine
  • blood in the urine
  • strong-smelling urine
  • a low-grade fever

If the infection spreads to the kidneys, a person may experience additional symptoms. These may include a high fever, shaking and chills, back pain, nausea, and vomiting. A doctor must be consulted in order to receive a diagnosis for the symptoms as well as a treatment for the condition.

Information About UTIs in Women

Although I focus on Proteus mirablis in this article, other species of bacteria can cause UTIs. Escherichia coli, or E. coli, is a common cause of an infection known as cystitis in the urinary bladder. It can also infect the lower part of the urinary tract.

Features of Proteus mirabilis Bacteria

Proteus mirabilis is an interesting, single-celled bacterium that exists in two different forms. These forms are known as swimmer cells and swarmer cells. Swimmer cells are rod-shaped and bear eight to ten thin, whip-like extensions called flagella. The flagella move and enable the bacterium to travel through a liquid. Each cell is one or two micrometers in length. A micrometer (µm) is a millionth of a meter or a thousandth of a millimeter.

When the swimmer cells settle on a surface, their structure changes. They become much longer—up to eighty µm in length—and develop many more flagella. The flagella are very thin and may not be visible in photos or videos. The cells are now known as swarmer cells. The swarmer cells form an arrangement called a raft. In the raft, the flagella of neighboring cells become interwoven. The bacteria in the raft coordinate their movements and the raft as a whole moves rapidly over a surface, acting almost like a multicellular creature.

Swarming Proteus mirabilis

Bacteria and Urinary Tract Infections

Proteus UTIs are uncommon in people with normal urinary tracts, although they do occur. Infections caused by specific strains of Escherichia coli are more frequent in this group of people. Proteus mirabilis infections are more common in people with structural abnormalities in their urinary tract that trap urine or in people who have a urinary catheter inserted in their body for a long period of time.

Proteus exhibits interesting behavior that may harm its host.

  • The bacterium contains an endotoxin in its cell wall. The toxin causes an inflammatory response in the host when it's released.
  • Fimbriae on the cell wall of the bacterium help it to adhere to the urinary tract lining and other surfaces. Frimbriae are fine extensions from a cell. They are shorter and thinner than flagella.
  • The bacterium can form stationary films on top of surfaces, including urinary catheters. Bacteria in films (biofilms) are harder to eradicate than free-living bacteria because they secrete a slime that protects their bodies.
  • Proteus can trigger the formation of mineral stones and crusts in the urinary tract of its host.

Facts About UTIs in Men and Women

Proteus mirabilis and Urinary Stones

Many people infected by Proteus mirabilis develop stones in their urinary tract. Proteus releases an enzyme called urease. Urease acts on urea, a waste substance in urine. It converts the urea into ammonia, a basic (alkaline) substance that causes the pH to rise. The increased pH triggers calcium phosphate in urine to become solid and form apatite crystals. It also triggers magnesium ammonium phospate to solidify, forming struvite crystals.

Crystals aggregate to form stones, which may block the flow of urine. Bacteria of multiple species may enter crevices in the stones and become difficult to eradicate with antibiotics. The crystals may also form crusts on the inside and outside of catheters. Crusts inside a catheter can interfere with urine flow.

Stones not only act as a reservoir for bacteria but also increase the chance of an infection spreading up the urinary tract to the urinary bladder. Bacteria may enter the pelvis of the kidneys and even the kidneys themselves, where they form new stones. Cystitis (infection and inflammation of the urinary bladder) and pyelonephritis (infection of the renal pelvis and kidneys) are often reported in people who have stones in the urinary tract.

These are struvite stones from a dog's urinary bladder. The same stones form in humans during a Proteus mirabilis infection

These are struvite stones from a dog's urinary bladder. The same stones form in humans during a Proteus mirabilis infection

Possible Treatments for the Infection

Antibiotics are often used to treat urinary tract infections. Catheters may be removed, at least until the infection has been cured. Once a person is better, a new catheter may be inserted if this is absolutely necessary. Stones that are large enough to cause problems may be broken up by a process called shockwave lithotripsy or by another method. Surgery may be used to remove large stones.

A doctor will be able to offer a patient advice based on the person’s condition and the latest discoveries about urinary tract infections and their treatment. It's possible that significant and helpful discoveries about the disorder will soon be made and that improved prevention methods and treatments will be devised.

In the future, a vaccine may be created to prevent a Proteus mirabilis infection in the urinary tract. Researchers have found that a preliminary version is effective in lab mice, as the last reference below describes. The vaccine enhances the aspects of the mouse immune system that attack the bacteria causing the problems. A vaccine that works in humans would be very helpful, since the infection is common in certain groups of people and is sometimes challenging to treat. The bacterium is an interesting organism to study, but it can cause significant problems.


This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

Questions & Answers

Question: How contagious is E. coli if it shows up in a catheter?

Answer: Hygiene is very important when someone has a catheter in place, especially when the urinary drainage bag is emptied or changed. Hygiene is also important when a patient has a known catheter-associated urinary tract infection with E. coli or another microbe.

A doctor or nurse must be consulted to learn the correct procedures for avoiding bacterial transfer both to and from a patient who has a catheter. The medical professional will be able to tell you about any risks and how to avoid them.

Question: What happens if a urinary tract infection doesn't get better?

Answer: Chronic urinary tract infections are ones that last a long time or reoccur. Despite the word “chronic” in their name, doctors can prescribe treatment methods that may suppress the symptoms. They can also suggest lifestyle changes that may help the condition.

A doctor may suggest a natural medicine if pharmaceutical ones don’t help. He or she should be consulted if you plan to use a natural medicine by yourself to discover any problems with it.

It may take time to find the best solution for a particular UTI or for recurring ones, but the effort is worth it to relieve discomfort.

Question: I recently had a UTI and experienced some major symptoms. I received medical treatment and finally feel better. Does this mean that the bacteria that caused the infection have disappeared?

Answer: Only a doctor can answer this question. He or she may have to order another urine analysis in order to give you an answer, but that decision is up to them. Since you experienced major symptoms that took some time to disappear, I think it’s important that you visit your doctor again.

© 2013 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on September 04, 2018:

Hi, Mo. Cats do experience Proteus mirabilis infections in their urinary tract, though I don’t know whether cats and humans are infected by the same strain of P. mirabilis. I haven’t seen reports of the bacterium in the digestive tract of cats, though it may occur there, as in humans. I’ve also seen no reports that the bacterium can pass to humans via cat feces.

Some diseases are zoonotic, or capable of passing from animals to humans, and cat feces can pass certain infectious agents to humans. None of the lists of these agents that I’ve seen have included Proteus mirabilis, however.

Mo on September 01, 2018:

Hi Linda, thank you for sharing your knowledge. I am a 32 y old male - otherwise healthy - and recently was diagnosed with my first UTI... The lab tests showed that Proteus is the culprit - my doctor was surprised as he said it is very rare for my gender and age...I'm not sure how I caught it....the only change in my environment the past couple of months is that I had to cat-sit for a friend who was that a possible mode of transmission (cleaning litter box than urinating for ex without properly washing hands?)

Linda Crampton (author) from British Columbia, Canada on January 03, 2018:

You should ask your doctor this question, Waseem. He or she is the best person to advise you.

Waseem Rehman on January 03, 2018:

I have a UTI problem and I am athlete . Running and abbs exercise may effect my body during UTI. Should I stop doing exercise untill I recover or carry on my exercises ?

Linda Crampton (author) from British Columbia, Canada on December 18, 2017:

I'm sorry that your husband is having such a difficult time. Some bacteria take a long while to defeat. Perhaps your husband could visit the doctor again to discuss the problem or visit another doctor if necessary. I hope he finds a solution soon.

Tammy on December 18, 2017:

So my husband has been fighting a uti for four months they give him antibiotics and it clears up and then comes right back. The doctor doesn't know why and neither does the urologist. The tests show E. coli every time but I don't know how he is getting it. He is a very clean person and showers daily. He is on a maintaining antibiotic that he takes daily and still keeps getting this infection. I don't know what to do anymore.

Linda Crampton (author) from British Columbia, Canada on November 12, 2015:

Hi, Peg. Thanks for the visit and the comment. UTIs are an interesting topic biologically, but they are very unpleasant to experience!

Peg Cole from North Dallas, Texas on November 12, 2015:

Fascinating information about these common infections. Over the years I've had my share of UTIs and never really understood what caused them. Also, I learned a lot about kidney stones. Had to have one of those removed some years back. This makes so much sense as to why they form.

Joanna Chandler from On Planet Earth on October 06, 2014:

Thank U Alicia ;)

Linda Crampton (author) from British Columbia, Canada on October 06, 2014:

I'm so sorry about your condition and the problems that you're experiencing, LadyFiddler. I hope new treatments are discovered very soon and that they improve your life. Best wishes to you. Thank you for commenting.

Joanna Chandler from On Planet Earth on October 06, 2014:

I some how wished they already had the vaccine. I am suffering with this said condition for about 1 1/2 yrs now it is awful. I have tried so many things, went to so many doctors , did so many tests and spend money like crazy. Yet i am truly suffering i urinate approximately on an average day 30 times sometimes more. I am not exaggerating the least i would go is about 20 times. I always have a toilet on my mind. I cannot hold the urine it burns my abdomen area if i really have to. I cannot go anywhere in peace least i need to use a rest room.

I am trusting God to harken unto me and have mercy and heal me.

Thanks for sharing.

Linda Crampton (author) from British Columbia, Canada on February 26, 2014:

Thank you very much for the comment, Christina. Good luck with your son's UTI's. I hope they don't return!

Christina on February 26, 2014:

Great article!

I have an almost 6 year old who has no history of UTI until 4 months ago when he got his first. Lab confirmed the 3 uti's caused by proteus mirabilis.

Renal ultrasound all perfect so we've been told likely cause is that he is not circumcised and doesn't drink much.

I increased fluid intake, cut back fats etc and fingers crossed no further uti's (early days yet)

Great article, thanks for the detail!

Linda Crampton (author) from British Columbia, Canada on October 06, 2013:

Thanks for the visit, CraftytotheCore. I appreciate your comment!

CraftytotheCore on October 06, 2013:

Very interesting! I never knew there was so much to a UTI. Those are very painful.

Linda Crampton (author) from British Columbia, Canada on March 13, 2013:

Hi, Deb. That's an interesting question. Some people claim that drinking lots of tea increases the risk of kidney stones due to the high level of oxalates that tea contains. I don't know if this has been proven scientifically, though. Thanks for the comment.

Deb Hirt from Stillwater, OK on March 13, 2013:

Great info, Alicia. When I was living elsewhere, a friend that I knew never drank water, always tea. He had stones a lot. Could that have been due to the fact that he never drank water?

Linda Crampton (author) from British Columbia, Canada on March 13, 2013:

Hi, Kathi. Yes, drinking lots of water is very important! Thanks for the visit and the comment.

Kathi Mirto from Fennville on March 13, 2013:

Hello Alicia, Drink lots more water, I have found that makes all the difference! Thanks for sharing very useful information. These are so common among us women and very painful!

Linda Crampton (author) from British Columbia, Canada on March 12, 2013:

Thanks for the comment, b. Malin. I appreciate your visit. Urinary tract infections are common in women. People who never get one are lucky!

b. Malin on March 12, 2013:

My Sister is prone to getting UTI, and yet I've never had one...Luck? As usual Alicia, a very Educational and most Informative read. I Never realized that Men can get them too...who knew? Once again, thanks for another well researched Hub.

Linda Crampton (author) from British Columbia, Canada on March 11, 2013:

Hi, Leah. The stones from the dog do look big. They must have been painful! I'm glad the surgery helped you with your infections. Thanks for the visit!

Leah Lefler from Western New York on March 11, 2013:

Oh, wow - the stones from the dog's bladder are so insanely big. I can't imagine having to pass one! I was prone to frequent bladder and kidney infections as a child (urinary reflux, grade V), but fortunately had surgery to prevent the backward flow of urine into my kidneys. I haven't had a bladder infection since - and fortunately have never had kidney stones!

Linda Crampton (author) from British Columbia, Canada on March 11, 2013:

Thank you for the visit and comment, drbj. I found the swarming video fascinating, but I didn't think of it as art when I first saw it. You're right, though, the scenes do look like abstract art!

drbj and sherry from south Florida on March 11, 2013:

Fascinating examination, Alicia, of urinary tract infections. The swarming proteus mirabilis bacteria in the video almost seem to be creating a series of abstract art images. Did you notice?

Linda Crampton (author) from British Columbia, Canada on March 11, 2013:

Thank you, Bill. I appreciate all your comments!

Bill Holland from Olympia, WA on March 11, 2013:

You continue to educate me and for that I am grateful.