Urinary Tract Infection


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One burning question: What is a urinary tract infection?

If you've had a urinary tract infection (UTI), you know the feeling. That urge to pee that suddenly arrives, the desperate run to the bathroom, to then pee just a couple of drops.

Ouch, it burns!

How do you get a UTI? A UTI occurs when unfriendly bacteria that usually live in the vagina or the gut make their way into the urethra and/or the bladder, grow, and cause inflammation [1].

80-90% of UTIs are caused by Escherichia coli. But other bacteria can also be involved:

  • Klebsiella pneumoniae
  • Staphylococcus saprophyticus
  • Enterococcus faecalis
  • Streptococcus agalactiae (Group B Strep)
  • Proteus mirabilis
  • Pseudomonas aeruginosa
  • Staphylococcus aureus [2]

Women are more likely than men to develop UTIs because their urethra is shorter. But there are also some things that may increase the risk of suffering these infections:

  • Having sex
  • Frequent pelvic exams
  • Using spermicides
  • Having a diaphragm
  • Pregnancy

Bacterial vaginosis [1], [3]–[5]

Consider yourself lucky if you've never had a UTI

UTI is one of the most common infections in women. About 50% of adult women will have at least one UTI in their life. And after the first episode, 27% will have a recurrent UTI within 6 months [6].

Pregnancy increases your risk of UTI due to hormonal and anatomical changes. About 2-15% pregnant women have asymptomatic presence of high numbers of bacteria in their urinary tract [7]. And about 1-2% develop an actual UTI [8].

Signs and symptoms of UTI

Unless you are one of those lucky women that have never experienced a UTI, you probably know the symptoms well:

  • Urge to pee
  • Difficulty starting urination
  • Pain or burning sensation when peeing
  • Peeing more often than normal
  • Lower abdomen discomfort, pelvic pressure
  • Blood in the urine

Other more severe symptoms may indicate the infection has reached the kidneys:

  • Fever
  • Chills
  • Nausea and vomiting
  • Back pain or pain in the flanks [1].

For some women, symptoms may start atypically and may be hard to relate these to a UTI. For example, you may have back pain for days without any other symptoms. If you suspect you may have a UTI or have had one in the past and you’re currently experiencing back or abdominal pain for several days, go see your provider. Taking your symptoms into account and performing a urine analysis will provide the correct diagnosis.

UTI-causing bacteria may originate from the vagina or the gut

Have you ever heard somebody say that urine is sterile? Well, turns out it’s not. Scientists have found that there is a microbiome in healthy urinary tracts. To no surprise, one of the most abundant bacteria in the urinary tract of healthy women are Lactobacillus species, the same that populate healthy vaginal microbiomes [9].

Scientists have identified various urotypes, that is, different types of urinary tract microbiomes. Some of the bacteria that can dominate these urotypes are Prevotella, Sneathia, Gardnerella, Atopobium, Lactobacillus, Shigella, Escherichia, Enterococcus, Streptococcus, and Citrobacter [10].

So then comes the obvious question, do bacteria in the urinary tract of women originate from the vagina? Scientists think the origin may be the vagina and/or the gut.

Let’s see first why some think UTI-causing bacteria come from the vagina:

  • One study found that the vaginal and bladder microbiome were very similar, but different from the gut microbiome [11].
  • Women with a history of recurrent or chronic UTI more commonly have E. coli in their vagina when compared to healthy women [12], [13]. Scientists think that this vaginal E. coli may contribute to recurrent UTI because in animal models with acute and chronic UTI, E. coli can invade and stay inside vaginal cells [14].
  • The vaginal microbiome of women with a history of UTI has low numbers of Lactobacillus [15]. And women with bacterial vaginosis are at increased risk of UTI [3]–[5].

But as we mentioned above, UTI-causing bacteria may also come from the gut:

  • One study found that 64% of bacterial species detected in the urine came from the gut, while only 32% came from the vagina [16].
  • Patients with UTI have high numbers of E. coli in their gut [17], [18].
  • High numbers of E. coli in the gut are associated with future development of UTI [19].

Besides, several beneficial gut bacteria have been found to be decreased in women with UTI, including Faecalibacterium, Akkermansia, Blautia, and Eubacterium hallii [20], [21].

Our Tiny Health gut test measures the levels of all these bacteria and tells you whether they are present below or above normal levels. Having low levels of protective bacteria and high levels of UTI-causing bacteria in your gut is one factor that may increase your risk of developing an UTI. 

It’s also worth testing your vaginal microbiome to check for high levels of UTI-associated bacteria such as E. coli.

An untreated UTI can lead to complications

When treated promptly, UTI rarely leads to complications. Untreated UTIs, on the other hand, can lead to serious consequences, such as:

  • Recurrent or chronic UTI
  • Permanent kidney damage, if the infection reaches the kidneys
  • Blood infection

During pregnancy, having a UTI may also increase the risk of other complications for both mom and baby. But not all studies agree on this:

  • Preterm birth. Some studies found that having a UTI during pregnancy increases the risk of preterm birth [22], [23]. But other studies found just a slight increase in the risk, which wasn’t clinically relevant [24], [25]. Another study didn’t find any association between UTI and preterm birth [26].
  • Preeclampsia. Two studies found an association between UTI and preeclampsia [24], [25], while another one didn’t [22]. 
  • Endometritis or mastitis. One study found that UTI during pregnancy increases the risk of the mom of suffering endometriosis or mastitis during the postpartum period [22].

Due to all these possible complications, the U.S. Preventive Services Task Force recommends that all pregnant women are screened for the asymptomatic presence of bacteria in urine at 12-16 weeks gestation or at the first prenatal visit. This is because a low percentage of women with high numbers of bacteria in the urine will progress to kidney infection if not treated [27].

Treatments for UTI

Sometimes a UTI will resolve on its own after a few days. But if symptoms persist and become more severe, antibiotics may be needed.

But what is the best antibiotic for a UTI?

Usually, providers will choose an antibiotic based on the resistance rate in the area you live in and will consider previous treatments if you have experienced a UTI in the past.

However, it’s possible that UTI-causing bacteria are resistant to antibiotics [28].

Therefore, if antibiotics are needed, consider asking for an antibiotic susceptibility test. Knowing exactly which antibiotic is the right one for you will increase the chances of a successful treatment.

However, an antibiotic susceptibility test takes 1-2 days for the results to be ready. Going to your provider early on can give them enough time to do this. But if the infection is in an advanced state, it might be better to just start on antibiotics to prevent complications. The test can still be done after you begin the treatment, and if needed treatment can be changed based on the test results.

Another advantage of the test is having different antibiotic choices, which can help your provider choose one that has a lower impact on your microbiome. If using a narrow-spectrum antibiotic is possible, it will get rid of the UTI-causing bacteria while causing less damage to the good guys (unlike a broad spectrum antibiotic, which will kill much more bacteria).

Common antibiotics used to treat UTI are:

  • Amoxicillin
  • Ampicillin
  • Nitrofurantoin
  • Trimethoprim-sulfamethoxazole
  • Cefaclor
  • Cefalexin

Nitrofurantoin and trimethoprim-sulfamethoxazole are not recommended during the first trimester of pregnancy and near delivery if an alternative treatment is available [29]. These may be used anyways if you are allergic to other alternatives, because the benefits outweigh the risks.

Things you can do to prevent UTI or get rid of it faster

Want to stay away from UTIs? here are some things that may help you prevent them:

  • Pee after sex. This will help to naturally clean the area surrounding the urethra.
  • Drink plenty of water. Drinking lots of liquids, especially water will help you urinate more often and get rid of any bacteria that try to camp in your urethra or bladder.
  • Take good care of your vagina. Check out our 10 Tips for Vaginal Health that will help you keep a healthy vaginal microbiome.
  • Eat more berries. Adding cranberries, berry juices, or cranberry extract supplements to your diet may help reduce the risk of UTI and contribute to faster healing [30]–[32].
  • Check your vitamin D levels. Some studies found that vitamin D deficiency may increase the risk of suffering a UTI [33], [34].
  • Consider taking a D-mannose supplement. Studies have shown that D-mannose is effective in reducing UTI symptoms and recurrence, and it can be as effective as antibiotics [35], [36]. If you’re pregnant, ask your provider before taking D-mannose.
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