A Guide to UTI Bacteria Types

Most of us have experienced the uncomfortable feeling of having a urinary tract infection, or UTI. While it is very common, especially for women, it’s important to know what having a UTI means and the different types of bacteria that can influence the development of one.

In this guide, we’ll go through each type of UTI bacteria in detail while informing you of all the possible symptoms and causes, as well as the ways you help prevent a UTI in the future.

Table of Contents

What Is a UTI?

An infection of the urinary system is known as a UTI. Your urethra, kidneys, or bladder may become infected with this form of infection.

Since urine is a byproduct of our kidneys, which operate a filtration system, it normally doesn’t contain bacteria. Urine is produced when waste materials and extra water are extracted from your circulation by the kidneys.

Urine typically passes through your urinary system uncontaminated. However, bacteria from the outside of the body can enter the urinary tract and cause issues like infection and inflammation, which is essentially what a UTI is.

What Are The Symptoms?

A UTI causes the urinary tract to become inflamed, therefore it may result in one or more of the following symptoms:

  • Pressure in the lower pelvis
  • Pain in the abdomen, side, or pelvic area
  • Frequent urination with urgency or incontinence
  • Abnormal urine color or strong-smelling urine
  • Painful urination
  • Bloody urine
  • Fever
  • Painful sexual intercourse
  • Fatigue
  • Vomiting
  • Genital pain
  • Chills
  • Confusion

What Causes UTIs?

There are many reasons why you might have contracted a UTI. These possible causes include:

  • Sexual activity – if you are sexually active and/or have a new sexual partner.
  • Menopause – circulating estrogen declines after menopause, which can cause changes in the urinary tract.
  • Catheter – those who can’t urinate on their own may use a catheter, which can accumulate bacteria if not cleaned properly.
  • Suppressed immune system – diabetes, lupus, and HIV are just some examples of autoimmune diseases that impair the body’s defense against bacteria.
  • Blockages – kidney stones or other blockages can trap urine in the bladder.
  • Recent procedure – an exam or surgery involving the urinary tract can leave you vulnerable to bacteria buildup.
  • Birth defects – some people are born with urinary tract defects, meaning they may have difficulty urinating and experience trapped urine.
  • Anatomy – there is a short distance between the urethra and anus for women, making it easier for bacteria to contaminate the urinary tract
  • Birth control – diaphragms as contraception can increase the risk of bacteria developing, as well as spermicidal agents.

UTI Bacteria Types

We must remember that different patients are more or less vulnerable to certain bacteria kinds when looking at UTI bacteria types. Also, the germs that are most likely to be responsible will depend on how you contracted your UTI.

Multiple bacteria can infect the urinary tract simultaneously in some circumstances; this condition is known in medicine as “polymicrobial infection.”

E. Coli

E. coli bacteria are the most frequently found bacteria in the urinary tract of 75%–80% of young, sexually active, non-pregnant women with an uncomplicated UTI. These gram-negative bacteria are prone to developing drug resistance.

E. coli can be identified in human excretions since it is abundant in our lower intestines. Although E. coli are beneficial and even useful in your intestines, they can be very harmful if they migrate elsewhere. Unfortunately, it’s extremely easy for E. coli to move from your anus to your vagina and urethra, where it can then easily cause a UTI.

When an opportunity arises that would not ordinarily exist, such as a host with a compromised immune system or a changed microbiota, the opportunistic bacteria seize it and flourish. Therefore, you’ll be more vulnerable to infection by opportunistic bacteria if your vaginal or intestinal flora is out of balance.


Gram-positive, lactic acid bacteria called enterococci may grow and live in either oxygen-containing environments or in environments with temperatures ranging from 10 to 45 °C and a pH of 4.6 to 9.

With enterococci accounting for between 15 to 30% of catheter-associated UTIs, or CAUTIs, and being the third most common cause of UTIs acquired in hospital settings, a urinary catheter is a significant risk factor.

The incidence of enterococcal UTIs is significantly higher in diabetics due to their weakened immune systems and inadequate bladder emptying. In around 10% of diabetic men, these bacteria can enter the circulation and cause prostate irritation.

Unfortunately, antibiotic-resistant Enterococcal superstrains are on the rise. E. faecalis in particular creates tough biofilms, which are notoriously difficult for antibiotics to penetrate and kill the bacteria.

Group B Streptococcus

The gram-positive chain-forming bacterium Group B Streptococcus (GBS) frequently resides in the female reproductive tract and lower stomach without manifesting any symptoms. Statistics indicate that just 1% to 2% of UTIs are brought on by the bug.

The two primary risk factors for developing a UTI brought on by this bacteria are advanced age and pregnancy. In fact, GBS UTIs in the elderly can be fatal.

A GBS UTI is more likely to occur in those with weakened immune systems, such as those with cancer, diabetes, or pre-existing abnormalities of the urinary tract including chronic kidney disease or kidney stones.

Even while GBS frequently goes unnoticed in pregnant women, its presence in the urine and/or the vagina can pose substantial risks to the mother and the baby. The infection could spread to the child’s bloodstream, which can be fatal if there is a GBS transfer during labor and delivery.

The Centers for Disease Control advises universal screening of all females at 35–37 weeks of pregnancy due to the significant risk of GBS problems in the fetus. Preventive IV antibiotics are suggested during labor and delivery if a woman tests positive for GBS.

Klebsiella Pneumoniae

Klebsiella pneumoniae is known to cause UTI and sepsis in newborns as well as hospital-acquired UTIs in adults. Antibiotic resistance, specifically carbapenem antibiotics, is another prominent trait of this gram-negative bacterium.

Humans are naturally host to the Klebsiella pneumoniae bacteria, but the frequency with which they appear depends on a number of variables. For instance, in some regions of the world as well as in a hospital context, carrier rates of Klebsiella pneumoniae in the population are much higher.

Patients of Asian ethnicity in particular are more likely to have this bacterium colonize their intestines. According to certain research, healthy adult Klebsiella pneumoniae stool carrier rates range from 19% in Japan to 88% in Malaysia.

Proteus Mirabilis

A long-term catheter user is more likely to contract the gram-negative bacteria Proteus mirabilis. Proteus mirabilis-caused catheter-associated urinary tract infections (CAUTI) are especially challenging to treat because they can build biofilms and become drug-resistant.

The urethra’s mucosal layer is susceptible to injury when a catheter is introduced, which compromises the natural barrier and promotes bacterial colonization. Additionally, the catheter tube acts as a highway for bacteria, facilitating its entry into the bladder and the development of biofilm colonies on its surface.

In addition to conventional UTIs, this bacteria may also result in risky, symptomless bacteriuria, particularly in the elderly and individuals with type-2 diabetes, which may result in a potentially fatal urosepsis.

Pseudomonas Aeruginosa

One of the gram-negative bacteria most frequently responsible for catheter-associated UTIs and infections in immunosuppressed individuals is Pseudomonas aeruginosa. Pseudomonas aeruginosa is one of the least studied bacteria, which means hospitals don’t know how to prevent and cure illnesses brought on by these microbes.

UTIs caused by Pseudomonas aeruginosa are unfortunately notoriously difficult to treat. This bacterium not only has a number of pathogenic mechanisms that enable it to propagate and resist antibiotics, but it also builds biofilms on catheter surfaces quickly, further shielding it from antibiotic attacks.

Staphylococcus Saprophyticus

Gram-positive bacteria called Staphylococcus saprophyticus are responsible for 10-15% of UTI cases. Staphylococcus saprophyticus UTIs affect young, sexually active women at a rate of about 40%.

Although Staphylococcus saprophyticus has several highly peculiar traits, it shares many clinical traits with E. coli-caused urinary tract infections. For instance, they are frequently discovered in the urinary tracts of girls and young women in the late summer and early fall. This bacterium causes fewer UTIs in postmenopausal women than in other women, and it is less common in the winter and spring.

Staphylococcus saprophyticus UTI is generally responsive to most antibiotics, including penicillin, and is less likely to result in bacteremia.

Other UTI Types

Polymicrobial UTIs

An infection brought on by multiple bacterial species is referred to as a polymicrobial UTI. Hospitals are a common source of polymicrobial UTIs, which are more frequently linked to urinary catheters.

E. coli is more typical in monomicrobial infections, but Pseudomonas aeruginosa is more frequently linked to polymicrobial infections than to monomicrobial infections.

Rare UTIs

These UTI bacteria types are far less common than the others. They are predominantly new bacteria that are still being studied:

  • Actinobaculum schaalii – a possible gram-positive bacteria that is resistant to common antibiotics for treating UTIs.
  • Aerococcus – gram-positive bacteria that form in clusters, causing bladder, blood, and kidney infection that is life-threatening if left untreated.
  • Corynebacterium urealyticum – a gram-positive bacteria that causes prolonged inflammation of the bladder and kidneys, as well as kidney stones.
  • Gardnerella vaginalis – is common in women with BV and can infect the kidneys and bladder.

How to Prevent UTIs?

While UTIs can happen often, there are a few steps you can take to prevent them from happening to you. 

Practice Good Hygiene

UTIs can frequently be avoided by maintaining proper personal hygiene. For women, this is especially important;  E. coli bacteria can travel from the rectum back into the body more easily in women because their urethras are shorter than those of men.

It’s advised to always wipe after a bowel movement from front to back to prevent this. In order to prevent infections, women should also maintain good hygiene during their menstrual cycle. UTIs can also be avoided by frequently changing pads and tampons, and avoiding the use of feminine deodorant.

Change Your Birth Control

If a woman uses a diaphragm for birth control, she may be more likely to develop a UTI. Consult your healthcare practitioner about alternative birth control methods if you’re using a diaphragm as contraception and experiencing recurrent UTIs.

Use Water-Based Lubricant During Sex

Use a water-based lubricant if you use one during intercourse and have vaginal dryness. Something that won’t irritate your urethra is advised because spermicidal lubricants can increase your risk of getting UTIs.

Change the Clothes You Wear

Avoiding wearing tight-fitting clothing can actually keep you dry and stop bacteria in the urinary tract from forming. You can also change to cotton underwear to avoid excessive moisture building up near your urethra.

Pay Attention to and Change Your Urination Habits

Urination can be very important in removing microorganisms from the body. Every time you empty your bladder, you are expelling the waste that is present in your urine from your body.

If you regularly get UTIs, frequent urination can help lower your risk of infection. This will be aided by drinking enough fluids, but you should also steer clear of foods and beverages that can aggravate your bladder. Alcohol, citrus juices, caffeinated beverages, and spicy foods are a few examples.

Additionally, make an effort to urinate right before and right after sex. This might aid in removing any microorganisms that may have been introduced during sexual activity. Additionally, you can wash your genital area with warm water both before and after sex.

Stay Hydrated

Increasing your daily fluid intake, particularly water can help your urinary system get rid of excess bacteria. It is recommended that you drink six to eight glasses of water per day.

Try Cranberry Juice

Many claim that cranberry juice can assist in the treatment or even prevention of a UTI. Although they are still researching the issue, researchers have not yet discovered a conclusive solution.

Although there is no scientific evidence to support it, it won’t harm to try. Adding a glass of unsweetened cranberry juice to your diet may help.

How Can DrHouse Help You?

DrHouse is a telehealth platform that provides you with quick and easy access to a board-certified online doctor. With our telemedicine service, you can get diagnosed and treated from the comfort of your own home.

Our clinicians are available 24/7 and can provide comprehensive treatment for UTIs. We’ll help diagnose the cause of your symptoms and provide the necessary prescription medications.

If you’re experiencing UTI symptoms, don’t hesitate to get in touch with us today. We’ll help you find the right treatment option that works for you.

Final Thoughts

UTIs are common, but it’s not wise to ignore them outright, especially if they keep coming back, so be sure to visit your medical provider if you’re concerned about a urinary tract infection. Hopefully, this guide has helped you understand more about UTIs and the different bacteria associated with them. 


Content on the DrHouse website is written by our medical content team and reviewed by qualified MDs, PhDs, NPs, and PharmDs. We follow strict content creation guidelines to ensure accurate medical information. However, this content is for informational purposes only and not a substitute for professional medical advice, diagnosis, or treatment. For more information read our medical disclaimer.

Always consult with your physician or other qualified health providers about medical concerns. Never disregard professional medical advice or delay seeking it based on what you read on this website.

If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.



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