II. Causes
- Normal Host
- Escherichia coli (80-90%)
- Staphylococcus Saprophyticus (10-15% of young women, 4% overall)
- More aggressive and Recurrent Urinary Tract Infections
- Associated with Pyelonephritis
- Klebsiella Pneumoniae (3-6%)
- Enterococcus (5%)
- Group B Streptococcus (3%)
- Proteus Mirabilis (2-3%)
- Pseudomonas Aeruginosa (1%)
-
Nephrolithiasis or Ureterolithiasis associated infection
- Proteus (urease positive)
- Klebsiella Pneumoniae
- Sexually Transmitted Infections
III. Risk factors: Complicated Cystitis
- Male gender
- Pregnancy
- Hospital acquired Urinary Tract Infection
- Prolonged urinary tract symptoms (>1 week)
- Poorly controlled Diabetes Mellitus
- Immunocompromised
- Underlying urologic disorder
- Vesicoureteral reflux
- Recurrent complicated Urinary Tract Infections
- Catheter associated Urinary Tract Infection
- Neurogenic Bladder dysfunction
- Polycystic Kidney Disease
- Urologic instrumentation or stenting
- Status Renal Transplant
- Urinary Tract Obstruction (e.g. Nephrolithiasis)
- Men with Prostatitis or BPH
IV. Symptoms
- Most suggestive of Urinary Tract Infection
- Dysuria (Likelihood Ratio 2.0)
- If absent, Likelihood Ratio 0.5
- Urinary Frequency (Likelihood Ratio 1.8)
- Hematuria (Likelihood Ratio 1.5)
- Occurs in 30% of cases
- Dysuria (Likelihood Ratio 2.0)
- Other symptoms with Urinary Tract Infection
- Urinary Urgency
- Suprapubic Pain (especially after voiding)
- Incomplete Bladder emptying
V. Differential Diagnosis
-
Dysuria
- See Dysuria
- See Dysuria in Children
- See Dysuria in Men
- See Dysuria in Women
-
Urethritis
- Pain at onset of urination
-
Vaginitis
- External Dysuria
- Vaginal irritation or discharge
-
Chlamydia Trachomatis
- Long, insidious onset
- Sexually active
-
Acute Pyelonephritis
- Fever, Flank Pain, and Nausea or Vomiting
- Risk factors for cystitis with occult Pyelonephritis
- Women (30% have subclinical Pyelonephritis)
- Pregnancy
- Diabetes Mellitus
- Immunocompromised patients
- Urinary Tract Infection under age 12 years
- Genitourinary comorbid condition
- Acute Urethral syndrome (Sterile or low urine Bacterial count)
- Sterile Pyuria
- Chlamydia (most common)
- Genitourinary Tuberculosis (classic sterile pyuria)
- Asymptomatic Bacteriuria (organisms isolated on Urine Culture, but often not responsible for cystitis)
VI. Labs
-
Urinalysis
- Urine Leukocyte Esterase (high Test Sensitivity but low Test Specificity)
-
Urine Nitrite (high Test Specificity approaches 90%, but low Test Sensitivity)
- Requires presence of Bacteria (e.g. E coli, Klebsiella, Proteus) capable of converting nitrates to nitrates
- Urine White Blood Cells on microscopy
-
Urine Culture
- Positive for >100k organisms
- Women with Dysuria have <100k organisms in 30% cases
- Of those with positive Urinalysis for UTI, only half are culture positive
- Indications
- Not needed in uncomplicated UTI (young, healthy non-pregnant women)
- Complicated UTI or atypical presentations
- Suspected Pyelonephritis
- Older adults
- Women age <65 years with Recurrent UTI (2 in last 6 months, 3 in last year)
- Treatment failure despite first choice Antibiotics
- History of resistant Urinary Tract Infections
- Positive for >100k organisms
- Other labs to consider in complicated UTI or Pyelonephritis
VII. Diagnosis: Findings suggestive of upper Urinary Tract Infection (Pyelonephritis)
- See Pyelonephritis
- Fever, chills
- Flank Pain
- Vomiting
- Pregnancy (second and third trimester are higher risk)
- Underlying urinary tract disorder
- History of Ureteral Stenting or other instrumentation
- Male patients
- Insulin Dependent Diabetes Mellitus
- HIV Infection
- Immunosuppressants (Chronic Corticosteroid use, status-post transplant)
- Extremes of age (very young or very old)
- Underwhelming presentations of upper tract disease
VIII. Diagnosis: Factors suggestive of complicated UTI
- Extremes of age (preadolescent, or over age 65 years)
- Chronic renal disease
- Diabetes Mellitus
- Immunodeficiency
- Pyelonephritis (upper Urinary Tract Infection)
- Pregnancy
- Male patients (esp. uncircumsized)
- Recent Urinary Tract Instrumentation
- Ureteral Stents
- Indwelling catheters (>2 weeks)
-
Ureterolithiasis
- Infected stone is an emergency
- Urologic abnormalities
- Neurogenic Bladder
- Polycystic Kidney Disease
IX. Diagnosis: Prediction Rule
- Background
- Self diagnosed UTI in women is a strong predictor of UTI
- Criteria
- New onset frequency and Dysuria
- Absent Vaginal Discharge and irritation
- Efficacy
- Pretest probability of UTI based on symptoms: 90%
- Probablity of UTI with negative Urinalysis: 23%
- Positive Predictive Value: 90%
- Interpretation
- May be treated without Urinalysis and Urine Culture
- Healthy patients without complicating risk factors or Pyelonephritis symptoms
- Editorial note: I do not recommended this (other Dysuria causes, Antibiotic Overuse)
- Alternative: Even dipstick testing alone is reasonably accurate, priced and fast
- May be treated without Urinalysis and Urine Culture
- Reference
X. Precautions
- Consider Sexually Transmitted Infection in Vaginitis or male Dysuria
- Consider Ureterolithiasis with Urinary Tract Infection (emergency) when Flank Pain is severe
- Empiric Antibiotic regimens should be based on local resistance rates
- Urine Culture is not needed in occasional, uncomplicated Urinary Tract Infection (young, healthy, non-pregnant women)
- Assume upper tract disease in findings listed above
- Adjust management strategy to treat upper tract (e.g. avoid Macrobid/Nitrofurantoin)
-
Asymptomatic Bacteriuria occurs in up to 20% of older women
- Resolves without Antibiotics within 1 week in 25-50% of patients
- Have adequate pretest probability for Urinary Tract Infection before Urinalysis in older women
XI. Management: General
- See UTI in Older Adults
- See UTI in Children
- See UTI in Pregnancy
- See Acute Pyelonephritis
-
General measures
- Maintain hydration (e.g. 1.5 to 2 Liters/day, or 48 to 64 oz/day)
- Analgesics (Acetaminophen or Ibuprofen)
-
Antibiotics
- Course
- Anticipate symptom relief within 36 hours of starting Antibiotics
- In uncomplicated UTI based on symptoms
- Considered delayed Antibiotics, starting if symptoms persist >2-3 days
- Antibiotic duration
- Uncomplicated treatment: 3 days (except as noted)
- Nitrofurantoin and Macrobid course is 5 days (was 7 days)
- Complicated treatment: 10 day course
- Uncomplicated treatment: 3 days (except as noted)
- Antibiotic Resistance increasing (including multi-drug resistance)
- Nitrofurantoin and Macrobid resistance low (1-2%)
- Beta Lactams: 20 to 55%
- Ampicillin: 38%
- Trimethoprim Sulfamethoxazole (Septra): 18 to 22%
- Fluoroquinolone resistance had been low, but as of 2024 resistance is as high as 21%
- Avoid as first line agents if possible (due to other adverse effects)
- Consider in areas of high Septra resistance areas
- Cure may occur despite resistance to Antibiotic used
- Risks for Antibiotic Resistance
- Trimethoprim Sulfamethoxazole within last 3-6 months
- Diabetes Mellitus
- Recent hospitalization
- Travel outside United States
- Resistance rates in community >20%
- Course
- Acute Uncomplicated UTI: First-Line agents
- Note that Ciprofloxacin has been demoted from first-line agent due to adverse effects (see below)
- Trimethoprim-Sulfamethoxazole (Bactrim) DS one orally twice daily for 3 days
- Avoid if local resistance rate >20%
- Nitrofurantoin (Macrobid)
- Macrobid 100 mg orally twice daily for 5 days
- Avoid if GFR <30 ml/min (risk of interstitial pulmonary fibrosis)
- Fosfomycin (Monurol) 3 grams for one dose
- Consider as a single dose in Emergency Department (e.g. patient non-compliant)
- More expensive and may be less effective (58% efficacy compared with 70% for Nitrofurantoin)
- First-line alternative agents for Acute Cystitis
- Cephalexin (Keflex) 500 mg orally twice daily for 5 to 7 days
- Cefuroxime (Ceftin) 500 mg orally twice daily for 5 to 7 days
- Acute Uncomplicated UTI with risks for resistance (prior Bactrim use or international travel in last 6 months)
- Nitrofurantoin
- Avoid if GFR <30 ml/min (risk of interstitial pulmonary fibrosis)
- Nitrofurantoin 100 mg orally four times daily for 5 days
- Macrobid 100 mg orally twice daily for 5 days
- Five days is sufficient course (previously used for 7 days)
- Gupta (2007) Arch Intern Med 167(20):2207-12 [PubMed]
- Fosfomycin (Monurol) 3 grams for one dose
- Also see Fluoroquinolones below
- Nitrofurantoin
- More severe disease or resistant UTI organisms: Fluoroquinolones
- Precautions regarding Fluoroquinolones
- Risk of Tendinopathy (and Achilles Tendon Rupture) and Peripheral Neuropathy
- Avoid if local resistance rate >10%
- Renal dose adjustment required if GFR reduced
- Although 3 day courses are listed, complicated UTI is treated for 10 days (up to 6 weeks in men)
- Ciprofloxacin 250 mg PO bid for 3 days
- In healthy older women, 3 days equivalent to 7 days
- Vogel (2004) CMAJ 170:469-73 [PubMed]
- Levofloxacin 250 mg every 24 hours for 3 days
- Norfloxacin 400 mg PO bid for 3 days
- Ofloxacin 200 mg PO bid for 3 days
- Avoid Moxifloxacin and Gemifloxacin (poor penetration into urine)
- Precautions regarding Fluoroquinolones
- Antibiotics for UTI in Pregnancy
-
Beta Lactam
Antibiotics used in Urinary Tract Infection
- Precautions
- Beta Lactams have lower efficacy in UTI
- First-line alternative agents for Acute Cystitis (see above)
- Cephalexin (Keflex) 500 mg orally twice daily for 5 to 7 days
- Cefuroxime (Ceftin) 500 mg orally twice daily for 5 to 7 days
- Cefdinir (Omnicef) 300 mg orally twice daily for 3 to 7 days
- Oral Third Generation Cephalosporin with broader coverage
- Amoxicillin-Clavulanate (Augmentin) 875 mg orally twice daily for 5 to 7 days
- Higher resistance rates
- Precautions
- Sexually active young patients
- Avoid Nitrofurantoin (Macrobid)
- Staphylococcus Saprophyticus resistance
- Consider Chlamydia sceening
- Consider other Sexually Transmitted Disease Testing
- Avoid Nitrofurantoin (Macrobid)
XII. Management: Special Circumstances
- See Recurrent Urinary Tract Infection
- See Catheter-Associated Urinary Tract Infection (CAUTI)
- Lower tract, uncomplicated UTI with resistant Enterobacteriaceae
- Trimethoprim-Sulfamethoxazole (Bactrim)
- Nitrofurantoin or Fosfomycin
- Single IV Dose Aminoglycoside
- ESBL (Extended Spectrum Beta-Lactamase) producing E Coli, Proteus and Klebsiella
- Fosfomycin (cystitis)
- Trimethoprim-Sulfamethoxazole (Bactrim) may be effective
- Carbapenem (e.g. Ertapenem)
-
Carbapenem-Resistant Enterobacteriaceae
- Trimethoprim-Sulfamethoxazole (Bactrim) or Fluoroquinolones may be effective
- Ceftazidime-Avibactam (Avycaz)
- Meropenem-Vaborbactam (Vabomere)
- Imipenem-Cilastin-relebactam (Recarbrio)
- Cefiderocol (Fetroja)
-
Pseudomonas Aeruginosa resistant Bacteria
- Ceftolozane-Tazobactam (Zerbaxa)
- Ceftazidime-Avibactam (Avycaz)
- Imipenem-Cilastin-relebactam (Recarbrio)
- Cefiderocol (Fetroja)
- References
XIII. Management: Asymptomatic Bacteriuria
XIV. Prevention
-
General measures in women
- Maintain adequate hydration
- Women should clean perineum wiping front to back
- Avoid Contraceptive Diaphragm
-
Herbals and OTC products that are associated with reduced Recurrent Urinary Tract Infection
- See Prevention of Recurrent Urinary Tract Infection
- Methenamine hippurate
- Cranberry products
- Contains proanthocyanidins which inhibit E. coli and other p-fimbriated Bacteria from adhering to urothelial cells
- Number needed to treart (NNT): 16 in women, 8 in children, 9 following Bladder intervention
- Johari (2024) Am Fam Physician 110(1): 23B [PubMed]
- Sexually active women
- Women should empty Bladder before, after intercourse
- Post-coital Antibiotics may prevent Recurrent Urinary Tract Infections
- Trimethoprim 100 mg after intercourse
-
Antibiotic prophylaxis (consider in Consultation with urology)
- Fosfomycin 3 grams every 10 days
- Nitrofurantion 50 to 100 mg daily
- Trimethoprim 100 mg once daily for 3 to 6 months
- Postmenopausal women
- Vaginal Estrogens may prevent Recurrent Urinary Tract Infections
XV. Complications: Surgical
-
Perinephric Abscess
- Urinary Tract Infection contiguous spread
- Contrast with renal abscess (hematogenous spread)
-
Emphysematous Pyelonephritis
- Seen in Diabetes Mellitus
- Requires surgical drainage (otherwise high mortality)
XVI. References
- McGann, Deal and Paparella (2024) Crit Dec Emerg Med 38(7): 25-30
- (2019) Sanford Guide, accessed on IOS 9/21/2019
- Colgan (2011) Am Fam Physician 84(7): 771-6 [PubMed]
- Ebell (2006) Am Fam Physician 73:293-6 [PubMed]
- Gupta (1999) JAMA 281:736-8 [PubMed]
- Gupta (2012) Ann Intern Med 156(5): ITC3-1 [PubMed]
- Hooton (1997) Infect Dis Clin North Am 11:551-81 [PubMed]
- Kurotschka (2024) Am Fam Physician 109(2): 167-74 [PubMed]
- Michels (2015) Am Fam Physician 92(9): 778-86 [PubMed]
Images: Related links to external sites (from Bing)
Related Studies
Definition (MSHCZE) | Zánětlivé reakce epitelu močového ústrojí na mikrobiální invazi. Časté jsou bakteriální infekce spojené s BAKTERIURIÍ a PYURIÍ. |
Definition (MEDLINEPLUS) |
The urinary system is the body's drainage system for removing wastes and extra water. It includes two kidneys, two ureters, a bladder, and a urethra. Urinary tract infections (UTIs) are the second most common type of infection in the body. You may have a UTI if you notice
People of any age or sex can get UTIs. But about four times as many women get UTIs as men. You're also at higher risk if you have diabetes, need a tube to drain your bladder, or have a spinal cord injury. If you think you have a UTI it is important to see your doctor. Your doctor can tell if you have a UTI with a urine test. Treatment is with antibiotics. NIH: National Institute of Diabetes and Digestive and Kidney Diseases |
Definition (NCI) | A bacterial infectious process affecting any part of the urinary tract, most commonly the bladder and the urethra. Symptoms include urinary urgency and frequency, burning sensation during urination, lower abdominal discomfort, and cloudy urine. |
Definition (NCI_CTCAE) | A disorder characterized by an infectious process involving the urinary tract, most commonly the bladder and the urethra. |
Definition (CSP) | infections affecting stuctures participating in the secretion and elimination of urine: the kidneys, ureters, urinary bladder and urethra. |
Definition (MSH) | Inflammatory responses of the epithelium of the URINARY TRACT to microbial invasions. They are often bacterial infections with associated BACTERIURIA and PYURIA. |
Concepts | Disease or Syndrome (T047) |
MSH | D014552 |
ICD9 | 599.0 |
ICD10 | N39.0 |
SnomedCT | 155897002, 197930008, 266635000, 266634001, 155896006, 197924008, 274110008, 68566005 |
LNC | LA6437-3 |
English | Urinary tract infection, Infection, Urinary Tract, Infections, Urinary Tract, Tract Infection, Urinary, Tract Infections, Urinary, Urinary Tract Infections, Urinary tract infection, site not specified, UTI, Urinary tract infections, Infection of urinary tract, Urinary tract infect.unsp.NOS, Urinary tract infection, site not specified NOS, URINARY TRACT INFECT, Urinary infection NOS, urinary tract infection (diagnosis), urinary tract infection, uti, Infection urinary tract, Urinary tract infection NOS, Urinary infection, Urin tract infection NOS, Urinary Tract Infections [Disease/Finding], urinary tract infection (UTI), utis, urinary tract infections, urinary infection, Urinary Tract Infection, Urinary tract infection, site not specified NOS (disorder), Infection - urinary NOS, Urinary tract infection (& [NOS]) (disorder), Urinary tract infection (& [NOS]), Urinary infection NOS (disorder), INFECTION, URINARY TRACT, Urinary Tract Infectious Disease, TRACT, INFECTION OF URINARY, URINARY TRACT INFECTION, Urinary tract infectious disease, UTI - Urinary tract infection, Urinary tract infectious disease (disorder), infected; urinary, infection; urinary tract, urinary; infection, urine; infected, Urinary tract infection, NOS, Urinary tract infectious disease, NOS, Urinary tract infection; site not specified |
Italian | Infezione delle vie urinarie, Infezione urinaria, Infezione delle vie urinarie NAS, Infezione delle vie urinarie, sito non specificato, Infezioni delle vie urinarie |
Dutch | urinaire infectie, urineweginfectie, op niet-gespecificeerde plaats, urineweginfectie NAO, infectie van de urinewegen, geïnfecteerd; urine, infectie; urinewegen, urine; geïnfecteerd, urine; infectie, Urineweginfectie, lokalisatie niet gespecificeerd, urineweginfecties, urineweginfectie, Infectie, urineweg-, Urineweginfectie |
French | Infection des voies urinaires SAI, IVU, Infection urinaire, Infection des voies urinaires, site non précisé, Infection des voie urinaires, INFECTION DE L'APPAREIL URINAIRE, Infection du tractus urinaire, Infections des voies urinaires, Infections urinaires |
German | Infektion der Harnwege, Harnwegsinfektion NNB, Harnwegsinfektion, Stelle nicht bekannt, UTI, HARNWEGSINFEKT, Harnwegsinfektion, Lokalisation nicht naeher bezeichnet, Harnwegsinfektion, Harnwegsinfektionen |
Portuguese | Infecção das vias urinárias, Infecção das vias urinárias NE, Infecção das vias urinárias de localização NE, Infecção urinária, INFECCAO DO TRACTO URINARIO, Infecções do Sistema Urinário, Infecção do tracto urinário, Infecções das vias urinárias, Infecções Urinárias |
Spanish | Infección del tracto urinario, localización no especificada, Infección urinaria, Infección del tracto urinario NEOM, ITU, INFECCION VIAS URINARIAS, infección urinaria, SAI, infección urinaria, SAI (trastorno), infección de la vía urinaria, localización no especificada, SAI, infección de la vía urinaria, localización no especificada, SAI (trastorno), enfermedad infecciosa de las vías urinarias, infección de las vías urinarias, infección urinaria (trastorno), infección urinaria, Infecciones del tracto urinario, Infección del tracto urinario, Infecciones Urinarias |
Japanese | 尿路感染, 尿路感染NOS, 尿路感染、部位不明, ニョウロカンセン, ニョウロカンセンNOS, ニョウロカンセンブイフメイ |
Swedish | Urinvägsinfektioner |
Czech | močové cesty - infekce, Infekce močových cest, blíže neurčené části, Infekční onemocnění močových cest, Infekce močových cest, Močová infekce, Infekce močových cest NOS, infekce močového ústrojí, močové ústrojí - infekce, močové infekce |
Finnish | Virtsatieinfektiot |
Russian | MOCHEVYKH PUTEI INFEKTSII, МОЧЕВЫХ ПУТЕЙ ИНФЕКЦИИ |
Korean | 부위가 명시되지 않은 요로 감염 |
Croatian | URINARNE INFEKCIJE |
Hungarian | Fertőzés, húgyúti, Húgyúti fertőzések, húgyúti fertőzés, Húgyúti fertőzés, húgyúti fertőzés k.m.n., húgyúti fertőzés, hely nem meghatározott, UTI |
Polish | Zakażenie układu moczowego, Infekcja dróg moczowych, Zakażenia dróg moczowych, Infekcje dróg moczowych |
Norwegian | Urinveisinfeksjoner |
Ontology: Acute cystitis (C0149523)
Definition (NCI) | An acute infection of the bladder. It is usually caused by bacteria. Signs and symptoms include increased frequency of urination, pain or burning during urination, fever, cloudy or bloody urine, and suprapubic pain. |
Concepts | Disease or Syndrome (T047) |
ICD9 | 595.0 |
ICD10 | N30.0 |
SnomedCT | 197833009, 155883005, 266628008, 68226007 |
Dutch | cystitis acuut, cystitis acuut NAO, acute cystitis, acuut; cystitis, cystitis; acuut, Acute cystitis |
French | Cystite aiguë, Cystite aiguë SAI |
German | akute Zystitis, Zystitis akut NNB, Akute Zystitis |
Italian | Cistite acuta, Cistite acuta NAS |
Portuguese | Cistite aguda, Cistite aguda NE |
Spanish | Cistitis aguda, Cistitis aguda NEOM, cistitis aguda (trastorno), cistitis aguda |
Japanese | 急性膀胱炎NOS, 急性膀胱炎, キュウセイボウコウエン, キュウセイボウコウエンNOS |
English | acute cystitis (diagnosis), acute cystitis, Cystitis acute, Cystitis acute NOS, Cystitis;acute, cystitis acute, Acute cystitis, Acute cystitis (disorder), cystitis; acute, acute; cystitis, Acute Cystitis |
Czech | Akutní cystitida NOS, Akutní cystitida |
Korean | 급성 방광염 |
Hungarian | Cystitis, acut k.m.n., cystitis acuta, Cystitis, acut |
Ontology: Infective cystitis (C0600041)
Definition (NCI) | An infectious process affecting the urinary bladder. |
Definition (NCI_CTCAE) | A disorder characterized by an infectious process involving the bladder. |
Concepts | Disease or Syndrome (T047) |
SnomedCT | 236620008 |
English | BLADDER INFECTION, Infective cystitis, Bladder infection, Bladder infection NOS, Infection bladder, Infectious Cystitis, Infection;bladder, bladder infection, infection of bladder, bladder infections, Bladder Infections, Infections, Bladder, Infective cystitis (diagnosis), cystitis infective, Infection of bladder, Infective cystitis (disorder), bladder; infection, infection; bladder |
Dutch | blaasinfectie NAO, infectie blaas, blaasinfectie, blaas; infectie, infectie; blaas |
French | Infection de la vessie, Infection de la vessie SAI, INFECTION VESICALE |
German | Blaseninfektion, Blaseninfektion NNB, Infektion der Blase, BLASENINFEKTION |
Italian | Infezione vescicale, Infezione vescicale NAS, Infezione della vescica |
Portuguese | Infecção da bexiga, Infecção da bexiga NE, INFECCAO VESICAL |
Spanish | Infección de vejiga, Infección vesical, Infección vesical NEOM, INFECCION VEJIGA URINARIA, cistitis infecciosa (trastorno), cistitis infecciosa, infección de la vejiga |
Japanese | 膀胱感染, 膀胱感染NOS, ボウコウカンセン, ボウコウカンセンNOS |
Czech | Infekce močového měchýře, Infekce močového měchýře NOS |
Hungarian | húgyhólyagfertőzés, húgyhólyagfertőzés k.m.n., Fertőzés húgyhólyag |