Bladder Infection: 13 Critical Signs & Safe Treatment

A bladder infection is a bacterial infection of the bladder, also called cystitis. Common symptoms include burning when you urinate, frequent bathroom trips, sudden urgency, and pressure or pain low in the abdomen. Most cases are treatable, but fever, vomiting, chills, or pain in your back or side can signal a kidney infection.

This article is for general information and education. It does not replace medical advice, diagnosis, or treatment.

A bladder infection is common, but not every burning or urgent trip to the bathroom is cystitis.

Kidney stones, vaginal infections, sexually transmitted infections, prostatitis, menopause related tissue changes, and bladder pain syndrome can feel similar. Getting the cause right matters because treatment is different.

For a wider overview, read our Urinary Tract Infection guide or visit the Kidney Health and Disease Hub.

What Is a Bladder Infection?

A bladder infection is an infection inside the bladder.

Doctors often call it cystitis.

It is the most common type of urinary tract infection, or UTI.

The urinary system includes:

• The kidneys
• The ureters
• The bladder
• The urethra

Your kidneys make urine. The ureters move urine to your bladder, where it is stored until you urinate through the urethra.

Most bladder infections happen when bacteria enter the urethra and travel upward into the bladder.

Escherichia coli, usually called E. coli, causes many infections because it normally lives in the bowel.

Bladder Infection vs UTI: Are They the Same?

Not exactly.

A bladder infection is one type of UTI.

The term UTI can describe infection in different parts of the urinary tract.

Our Bladder Infection vs UTI guide explains the difference in more detail.

13 Important Bladder Infection Symptoms

1. Burning When You Urinate

Burning urination is one of the best known signs of cystitis.

It may feel like stinging, heat, or sharp irritation while urine passes.

Burning alone is not enough to prove a bladder infection because vaginal irritation, urethritis, and some sexually transmitted infections can cause the same feeling.

2. Frequent Urination

You may need the bathroom far more often than usual.

This can happen even when your bladder holds only a small amount of urine.

3. Sudden Urinary Urgency

Urinary urgency means a strong need to urinate comes suddenly and feels hard to delay.

The bladder lining becomes irritated, so it may send a strong signal even when the bladder is not full.

4. Passing Small Amounts of Urine

You may rush to the bathroom and then pass only a little urine.

This often happens together with frequency and urgency.

5. Lower Abdominal Pain

Lower abdominal pain from a bladder infection is often felt just above the pubic bone.

You may describe it as:

• Pressure
• Heaviness
• Aching
• Cramping
• Tenderness

6. Bladder Pressure

Some people feel that the bladder stays full even after they urinate.

This sensation can come from inflammation.

If you truly cannot empty your bladder, especially if you are in pain, seek medical help.

7. Cloudy Urine

Urine may look cloudy during infection.

This can happen because of white blood cells, bacteria, blood, or other material.

Cloudy urine by itself does not prove infection.

8. Blood in the Urine

A bladder infection can cause visible or microscopic blood.

Your urine may look pink, red, or brown.

Kidney stones and other urinary conditions can also cause blood, so persistent bleeding needs further assessment.

9. Strong Smelling Urine

Urine odor may change during a bladder infection.

Still, smell alone is a poor test for infection.

Food, supplements, medicines, and dehydration can all change urine odor.

10. Pelvic Discomfort

Some people feel pressure or aching in the middle of the pelvis.

Repeated pelvic pain with negative urine cultures should prompt a search for another cause.

11. Feeling Tired or Unwell

A bladder infection can make you feel tired or uncomfortable.

Feeling severely ill is less typical of infection confined to the bladder and deserves quicker assessment.

12. Fever or Chills

Fever is an important warning sign.

A significant fever or shaking chills can mean the infection has moved beyond the bladder.

13. Back or Side Pain, Nausea, or Vomiting

These are not ordinary cystitis symptoms.

Pain under the ribs in your back or side, especially with nausea, vomiting, fever, or chills, raises concern for a kidney infection.

Bladder Infection vs Kidney Infection

This difference matters because kidney infection can become serious much faster.

What Causes a Bladder Infection?

Bacteria are the most common cause.

The bacteria usually enter through the urethra and multiply in the bladder.

E. coli from the bowel is a frequent cause.

Female Anatomy

Women develop bladder infections more often because the urethra is shorter and located closer to the anus.

This gives bacteria a shorter route to the bladder.

Sexual Activity

Sex can move bacteria toward the urethral opening.

A UTI is not automatically a sexually transmitted infection.

Spermicides and Diaphragms

Some contraceptive methods can increase infection risk in people who get repeated UTIs.

Pregnancy

Pregnancy changes the urinary tract and makes prompt diagnosis more important.

Menopause

Lower estrogen changes the tissues and bacterial environment around the vagina and urethra.

This can raise the risk of recurrent infection.

Incomplete Bladder Emptying

Urine that remains in the bladder can make infection more likely.

Possible causes include:

• Enlarged prostate
• Urinary blockage
• Nerve problems
• Bladder muscle problems
• Some medicines

Kidney or Bladder Stones

Stones can interfere with urine flow and may contribute to repeated infection.

See our Kidney Stones Symptoms guide.

Urinary Catheters

Catheters create another route for bacteria to enter the urinary tract.

Diabetes

Diabetes can raise the risk of urinary infection.

Our Type 2 Diabetes guide explains the wider health picture.

Does Dehydration Cause Bladder Infection?

Dehydration does not create bacteria by itself.

Still, drinking enough fluid supports normal urine flow and may help reduce infection risk in some people.

There is no universal rule that everyone must drink eight or ten glasses.

Your fluid needs depend on body size, weather, activity, pregnancy, kidney function, heart health, and other factors.

If a healthcare professional has given you a fluid limit, follow that advice.

Does Holding Urine Cause Bladder Infection?

Holding your urine once does not automatically cause infection.

Regular bladder emptying is still healthy.

The bigger risk is chronic incomplete emptying, when a meaningful amount of urine remains in the bladder after you urinate.

Do Tight Clothes Cause Bladder Infection?

Tight clothes are not a major established cause of bacterial cystitis.

Loose and comfortable clothing may reduce skin irritation and moisture, but anatomy, bladder emptying, pregnancy, menopause, stones, catheters, diabetes, and previous UTIs are stronger risk factors.

Is Bladder Infection Caused by Poor Hygiene?

No.

People who get UTIs are not necessarily unclean.

Harsh soaps, douching, and aggressive washing can irritate genital tissue without preventing infection.

For girls and women, wiping from front to back is a sensible habit because it can reduce movement of bowel bacteria toward the urethra.

What Can Be Mistaken for a Bladder Infection?

How Is a Bladder Infection Diagnosed?

A healthcare professional may use your symptoms, health history, physical exam, and urine tests.

Urinalysis

Urinalysis can check for:

• White blood cells
• Blood
• Nitrites
• Other urine changes

A positive result can support the diagnosis, but a dipstick is not perfect.

Urine Culture

A urine culture can identify bacteria and help show which antibiotics are likely to work.

The result usually takes longer than a basic urinalysis.

Blood Tests

Blood tests may be needed when a more serious infection is possible.

They can also help assess kidney function.

Imaging or Cystoscopy

These tests are not needed for every simple bladder infection.

They may be considered when infections repeatedly return or when a stone, blockage, structural problem, or other condition is suspected.

Visit our Medical Tests and Screenings Hub for more test guides.

When Does Urine Culture Matter More?

Culture is particularly useful when:

• You are pregnant
• You are male
• The symptoms are unusual
• You have recurrent infections
• A kidney infection is possible
• The first treatment does not work
• You recently used antibiotics
• Antibiotic resistance is a concern
• You have a catheter

Can a Home UTI Test Confirm Bladder Infection?

No.

A home urine strip can detect findings such as nitrites or leukocyte activity.

It cannot tell you:

• Exactly which bacteria are present
• Which antibiotic will work
• Whether the kidneys are infected
• Whether the prostate is involved
• Whether an STI is causing the symptoms

Do not delay medical care because one home strip is negative.

How Is a Bladder Infection Treated?

Bladder infection treatment depends on whether bacteria are causing the symptoms and on your individual risk factors.

When bacterial cystitis needs antibiotic treatment, the antibiotic should be chosen for the patient and infection rather than copied from someone else's prescription.

Factors include:

• Pregnancy
• Sex
• Kidney function
• Medicine allergies
• Previous urine culture results
• Recent antibiotic use
• Local resistance patterns
• Possible kidney or prostate involvement

Antibiotics

UTI antibiotics kill or stop the growth of bacteria.

Use the medicine exactly as prescribed.

Do not share antibiotics, and do not use leftover tablets from another infection.

Why Culture Results Can Change Treatment

Bacteria are not equally sensitive to every antibiotic.

If a culture shows resistance, the healthcare professional may change treatment.

Using a narrower antibiotic when possible also helps reduce unnecessary antibiotic exposure.

Do All Bladder Infections Need Immediate Antibiotics?

The answer depends on the person.

NICE guidance allows some nonpregnant women with mild lower UTI to receive either immediate antibiotics or a backup prescription, depending on symptoms and risk.

Pregnant people and men with lower UTI are managed differently and are generally offered immediate antibiotic treatment in NICE guidance.

Children also need age appropriate medical assessment.

Do not use this distinction to self diagnose whether you can safely wait.

How Fast Should Bladder Infection Symptoms Improve?

Many people begin to improve after effective treatment starts.

You should be reassessed if:

• Symptoms worsen quickly
• A fever develops
• You develop back or side pain
• You begin vomiting
• You become much more unwell
• Symptoms have not started improving after about 48 hours of antibiotics

These changes can mean resistant bacteria, the wrong diagnosis, or infection beyond the bladder.

How Can You Ease Bladder Infection Pain?

Drink Enough Fluid

Drink enough water to avoid dehydration unless you have been told to limit fluid.

Water may make concentrated urine less irritating.

It does not replace antibiotic treatment when antibiotics are needed.

Use Suitable Pain Relief

Paracetamol, also called acetaminophen, may help pain or fever when safe for you.

Ibuprofen may be another option for some people.

Ask a pharmacist or clinician if you have kidney disease, stomach ulcers, take blood thinning medicine, are pregnant, or have another condition that changes pain medicine safety.

Use Gentle Heat

A heating pad over the lower abdomen may ease bladder discomfort.

Keep it comfortably warm rather than very hot.

Phenazopyridine

Where available, phenazopyridine may reduce urinary burning, urgency, frequency, and pain.

It is not an antibiotic.

It does not cure the infection.

It can turn urine orange or red orange.

Ask a healthcare professional whether it is safe for you, especially if you have kidney disease.

Can Water Flush Out a Bladder Infection?

Water supports hydration and normal urine flow.

It may also reduce the sting caused by very concentrated urine.

But water does not reliably clear bacteria from an active bladder infection.

Think of hydration as support, not a cure.

Does Cranberry Juice Cure a Bladder Infection?

No.

Research has focused mainly on whether cranberry can reduce future UTIs in people who get recurrent infections.

Cranberry juice, capsules, or extracts do not treat an infection that is already active.

Does D Mannose Treat Bladder Infection?

No good evidence supports D mannose as a treatment for an active bladder infection.

It has also been studied for recurrence prevention, but current urology guidance does not support promising that D mannose alone will prevent future UTIs.

Does Vitamin C Treat Cystitis?

No reliable evidence shows that vitamin C cures a bacterial bladder infection.

Fruit belongs in a healthy diet, but high dose vitamin C should not replace medical treatment.

Do Probiotics Cure Bladder Infection?

No.

Probiotics are being studied for possible prevention roles, but they do not replace antibiotics for an active bacterial infection that needs treatment.

Should You Drink Baking Soda for a Bladder Infection?

No.

Baking soda does not kill UTI bacteria.

Large doses can also alter sodium and acid balance in the body.

This can be especially risky for people with kidney disease, heart disease, high blood pressure, or certain medicines.

Can Food Treat a Bladder Infection?

No specific food has been proven to cure cystitis.

NIDDK states that diet is not considered a treatment for bladder infection.

During recovery, choose food and drinks that feel comfortable and support normal hydration.

If coffee, alcohol, energy drinks, or acidic beverages make burning or urgency worse, it is reasonable to reduce them temporarily.

Bladder Infection in Women

Women develop bladder infections more often because of urinary anatomy.

Risk may also rise with:

• Sexual activity
• Spermicide use
• Pregnancy
• Menopause
• A previous UTI

Read our detailed UTI Symptoms in Women guide.

Bladder Infection in Men

Men can get bladder infections too.

Male urinary symptoms need careful assessment because other conditions can overlap.

These include:

• Prostatitis
• Enlarged prostate
• Urinary retention
• Kidney stones
• Urethritis

Our UTI Symptoms in Men guide explains these differences.

Bladder Infection During Pregnancy

Possible bladder infection during pregnancy should be assessed promptly.

Pregnancy itself can make you urinate more often, so frequency alone can be confusing.

Burning, bladder pain, blood in urine, fever, or back pain deserve attention.

ACOG recommends urine culture when a pregnant patient has symptoms of acute cystitis.

Confirmed cystitis during pregnancy is treated with an appropriate antibiotic.

Kidney infection during pregnancy can cause serious complications, so do not wait several days for symptoms to clear on their own.

Bladder Infection After Menopause

UTIs often become more common after menopause.

Lower estrogen can change:

• Vaginal tissue
• Urethral tissue
• The vaginal microbiome

Some people also develop dryness, burning, painful sex, and recurrent urinary symptoms.

This is often called genitourinary syndrome of menopause.

Vaginal Estrogen

Current American Urological Association guidance recommends vaginal estrogen for appropriate perimenopausal and postmenopausal women with recurrent UTIs when there is no contraindication.

It is used for prevention, not as treatment for an active bacterial infection.

What Is Asymptomatic Bacteriuria?

Asymptomatic bacteriuria means bacteria are found in urine even though you do not have UTI symptoms.

This is not the same as symptomatic bladder infection.

Most nonpregnant adults with asymptomatic bacteriuria do not need antibiotics solely because bacteria appeared on a urine test.

Important exceptions include pregnancy and certain urinary procedures.

Why This Matters in Older Adults

Bacteria may be found in the urine of older adults without causing a symptomatic infection.

New confusion alone does not prove bladder infection.

Other causes can include:

• Dehydration
• Medicine effects
• Low oxygen
• Stroke
• Pain
• Electrolyte problems
• Urinary retention
• Another infection

If an older person is severely ill, confused, feverish, or has low blood pressure, urgent medical assessment is appropriate.

What Counts as Recurrent Bladder Infection?

A common definition for recurrent UTI in women is:

• Two or more infections in six months
• Three or more infections in twelve months

Repeated symptoms deserve more than repeated guesses.

Ask whether the infections are being confirmed and whether an underlying factor is present.

Why Do Bladder Infections Keep Coming Back?

Possible reasons include:

• Previous UTIs
• Sexual activity
• Spermicides
• Menopause
• Poor bladder emptying
• Enlarged prostate
• Kidney stones
• Bladder stones
• Urinary catheters
• Diabetes
• Structural urinary problems
• Antibiotic resistant bacteria

How Can You Prevent Bladder Infections?

1. Stay Hydrated

Drink enough fluid for your health needs.

2. Empty Your Bladder Normally

Use the bathroom when you need to and take enough time to empty the bladder comfortably.

3. Wipe From Front to Back

This habit can help keep bowel bacteria away from the urethral opening in women and girls.

4. Avoid Vaginal Douching

The vagina does not need internal cleaning.

Douching and scented sprays can cause irritation.

5. Review Contraception if UTIs Keep Returning

Spermicides and diaphragms may raise UTI risk in some people.

6. Urinate After Sex

This is a simple low risk habit commonly included in prevention advice.

It cannot guarantee that a UTI will not occur.

7. Treat Bladder Emptying Problems

If urine remains in the bladder because of prostate enlargement, nerve disease, stones, or another problem, treating the underlying cause can be important.

8. Consider Vaginal Estrogen When Appropriate

For suitable people after menopause with recurrent infection, local vaginal estrogen can reduce future UTI risk.

9. Discuss Recurrent UTI Prevention

Some people may be offered:

• Cranberry as a prevention option
• Trigger based antibiotic prevention
• Daily low dose antibiotic prevention
• Other clinician guided preventive treatments

The best plan depends on the person and the cause of recurrence.

When Should You Contact a Healthcare Professional?

Contact a healthcare professional when you develop symptoms that suggest a bladder infection.

Seek advice sooner if:

• You are pregnant
• You are male
• You have diabetes
• You have kidney disease
• You have a weakened immune system
• You use a catheter
• You have recurrent UTIs
• You have known stones
• You see blood in your urine
• Your symptoms are severe
• Symptoms return shortly after treatment

When Is a Bladder Infection More Urgent?

Get prompt medical care for:

• Fever
• Shaking chills
• Back or side pain
• Nausea
• Repeated vomiting
• Severe weakness
• Difficulty keeping fluids down
• Rapidly worsening symptoms

These signs can occur when infection has moved beyond the bladder.

When Is It an Emergency?

Seek emergency help for:

• Severe confusion
• Fainting or collapse
• Severe breathing difficulty
• Very fast breathing with severe illness
• Very little or no urine
• Cold, pale, blue, gray, or mottled skin
• Rapid deterioration
• Signs of sepsis

Conclusion: Treat Bladder Infection Safely

A bladder infection often causes burning, urgency, frequent urination, and lower abdominal pressure. Most bacterial cases can be treated successfully once the diagnosis is clear.

Water, pain relief, and gentle heat can make symptoms easier to manage, but they do not replace antibiotics when antibiotic treatment is needed. Cranberry belongs in the prevention discussion, not on a list of cures.

Pay special attention to fever, chills, vomiting, or back and side pain because these symptoms can mean infection has reached a kidney.

If infections keep coming back, ask why rather than repeating the same remedy. Finding the cause can be the most important step toward preventing the next episode.

References and Sources

1. Centers for Disease Control and Prevention. Urinary Tract Infection Basics. Updated and reviewed September 22, 2026. Covers UTI symptoms, bladder and kidney infection, treatment, risk factors, prevention, and asymptomatic bacteriuria.
   https://www.cdc.gov/uti/about/
2. Centers for Disease Control and Prevention. Clinical Overview of Urinary Tract Infections. Updated July 16, 2026. Reviews cystitis, pyelonephritis, bacterial causes, testing, management, and antibiotic stewardship.
   https://www.cdc.gov/uti/hcp/clinical-overview/
3. National Institute of Diabetes and Digestive and Kidney Diseases. Bladder Infection in Adults. NIH guidance on cystitis symptoms, causes, diagnosis, treatment, and complications.
   https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults/
4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and Causes of Bladder Infection in Adults. Covers burning, urgency, lower abdominal discomfort, cloudy or bloody urine, and kidney infection warning signs.
   https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults/symptoms-causes
5. National Institute of Diabetes and Digestive and Kidney Diseases. Diagnosis of Bladder Infection in Adults. Guidance on urinalysis, urine culture, blood tests, imaging, and cystoscopy.
   https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults/diagnosis
6. National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for Bladder Infection in Adults. Covers antibiotics, fluids, pain relief, heating pads, recurrent infection, vaginal estrogen, and kidney infection complications.
   https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults/treatment
7. National Institute for Health and Care Excellence. Lower UTI: Antimicrobial Prescribing. Guidance on antibiotics, delayed prescriptions in selected nonpregnant women, pregnancy, men, pain relief, hydration, culture, and reassessment after 48 hours.
   https://www.nice.org.uk/guidance/ng109/chapter/Recommendations
8. American Urological Association. Recurrent Uncomplicated Urinary Tract Infections in Women Guideline, amended 2025. Covers recurrent UTI evaluation, cranberry, D mannose, vaginal estrogen, and prevention strategies.
   https://www.auanet.org/guidelines-and-quality/guidelines/recurrent-uti
9. American College of Obstetricians and Gynecologists. Urinary Tract Infections. Covers bladder infection in women, pregnancy, recurrent infection, menopause, prevention, and antibiotic treatment.
   https://www.acog.org/womens-health/faqs/urinary-tract-infections
10. National Institute of Diabetes and Digestive and Kidney Diseases. Eating, Diet, and Nutrition for Bladder Infection in Adults. Explains that food does not treat bladder infection and cranberry does not treat an existing infection.
    https://www.niddk.nih.gov/health-information/urologic-diseases/bladder-infection-uti-in-adults/eating-diet-nutrition

Internal Links and Hub

• Kidney Health and Disease Hub
• Women’s Health Hub
• Men’s Health Hub
• Medical Tests and Screenings Hub
• Urinary Tract Infection
• UTI Symptoms
• UTI Symptoms in Women
• UTI Symptoms in Men
• How to Get Rid of a UTI Fast
• How to Get Rid of a UTI Fast Female
• Bladder Infection vs UTI
• Kidney Stones
• Kidney Stones Symptoms
• Kidney Disease Symptoms
• Type 2 Diabetes

About the Author

Frequently Asked Questions

What is a bladder infection?

A bladder infection is an infection inside the bladder, usually caused by bacteria. It is also called cystitis and is the most common type of urinary tract infection.

What are the most common bladder infection symptoms?

Common symptoms include burning when urinating, frequent urination, sudden urgency, lower abdominal pressure or pain, cloudy urine, and sometimes blood in the urine.

What is the difference between a bladder infection and a UTI?

A bladder infection is one type of UTI. A UTI can also affect the urethra or kidneys, while a bladder infection specifically affects the bladder.

How can you tell if a bladder infection has reached the kidneys?

Fever, shaking chills, nausea, vomiting, and pain in the back, side, or groin can indicate kidney infection and need prompt medical care.

Does cloudy urine always mean bladder infection?

No. Cloudy urine can occur with cystitis, but other factors such as crystals or genital discharge can also change urine appearance.

Does smelly urine mean bladder infection?

No. A bladder infection can change urine odor, but dehydration, food, vitamins, and medicines can also make urine smell stronger.

Can a bladder infection cause blood in urine?

Yes. Bladder inflammation can cause visible or microscopic blood. Blood that remains after treatment or keeps returning needs further medical assessment.

How is a bladder infection diagnosed?

Diagnosis may involve your symptoms, medical history, urinalysis, and sometimes a urine culture. Blood tests or imaging may be needed when infection is severe or keeps returning.

What does a urine culture show?

A urine culture can identify bacteria growing in the urine and help show which antibiotics are likely to work.

Do bladder infections need antibiotics?

Bacterial bladder infections often need antibiotics, but treatment depends on the person, symptoms, pregnancy status, sex, infection severity, and risk of complications.

How fast should a bladder infection improve?

Symptoms should begin improving after effective treatment starts. Seek reassessment if symptoms worsen or have not started improving within about 48 hours of antibiotics.

Can water cure a bladder infection?

No. Water supports hydration and may make urination less irritating, but it does not reliably clear an active bacterial infection.

Can cranberry juice cure a bladder infection?

No. Cranberry may help reduce future infections in some people, but it does not treat an active bladder infection.

Does D mannose treat a bladder infection?

No good evidence supports D mannose as treatment for active cystitis. Current urology guidance also does not support promising that D mannose alone prevents recurrent UTI.

Does vitamin C cure a bladder infection?

No reliable evidence shows that vitamin C cures bacterial cystitis. It should not replace proper diagnosis or treatment.

Do probiotics cure bladder infection?

No. Probiotics are not an established treatment for active bacterial cystitis.

Can a bladder infection happen during pregnancy?

Yes. Possible bladder infection during pregnancy should be assessed promptly. Urine culture and an appropriate antibiotic are commonly used because untreated infection can progress to kidney infection.

Why do bladder infections increase after menopause?

Lower estrogen can change vaginal and urinary tissues and the local microbiome. These changes may increase recurrent UTI risk.

Can vaginal estrogen prevent recurrent bladder infections?

Yes. Current urology guidance recommends vaginal estrogen for appropriate perimenopausal and postmenopausal women with recurrent UTIs when there is no contraindication.

What is asymptomatic bacteriuria?

Asymptomatic bacteriuria means bacteria are present in urine without UTI symptoms. Most nonpregnant adults do not need antibiotics for this finding alone.

When should a bladder infection be treated urgently?

Get prompt medical care for fever, shaking chills, vomiting, back or side pain, severe weakness, inability to keep fluids down, or rapidly worsening symptoms.

When is a bladder infection an emergency?

Seek emergency help for severe confusion, fainting, serious breathing trouble, very little urine during severe illness, rapid deterioration, or other signs of sepsis.