Urinary Tract Infections (UTI) Adults

Sterile Pyuria

• Definition: Presence of pus cells but a sterile urine culture.
• Causes:
  • Contamination
  • Already treated infection
  • Bladder tumour
  • Tuberculosis (TB)
  • Appendicitis
  • Analgesic nephropathy

Asymptomatic Bacteriuria

• Definition: Significant growth of bacteria in urine but no symptoms.
• Prevalence:
  • More common in sexually active women and those with urinary tract abnormalities.
  • in Pregnancy
    • Untreated bacteriuria increases the risk of developing pyelonephritis by 20-30% due to physiological changes in the urinary tract during pregnancy.
    • Complications: May lead to preterm birth and low birth weight.
    • Benefit of Treatment: Reduces risk of symptomatic UTI.
    • Screening:
      • Perform urine culture and susceptibility testing at 12-16 weeks gestation or first antenatal visit.
      • Confirm with a second urine culture.
    • Treatment:
      • Use susceptibility results to guide therapy.
      • Follow up with a urine culture 1-2 weeks after treatment.
      • Special Consideration: If GBS is detected, intrapartum prophylaxis is indicated.

Symptomatic Bacteriuria

• Symptoms: Frequency, dysuria, and loin pain.
• Diagnosis: Significant bacterial growth on culture.

Acute Cystitis

from eTG

• Definition: Inflammation of the bladder and urethra.
• Symptoms:
  • Acute dysuria, frequency, urgency
  • Occasionally, suprapubic tenderness
  • Consider acute pyelonephritis if there is flank pain, vomiting, fever (≥38°C), or costovertebral tenderness.

Differential Diagnosis

• Consider sexually transmitted infections (e.g., urethritis, cervicitis).
• Consider vulvovaginitis in women with vaginal discharge.
• Cystitis in men is uncommon; consider prostatitis if there is fever, obstructive urinary symptoms, or prostate tenderness.

Investigations for Acute Cystitis in Adults

• When to Obtain Urine Culture:
  • Pregnant women
  • Men
  • Aged-care facility residents
  • Recent antibiotic use
  • Recurrent infection
  • Risk factors for multidrug-resistant bacteria
  • Patients not responding to empirical therapy
• Diagnosis Confirmation:
  • Bacteriuria: ≥108 CFU/L from a midstream urine sample.
  • Lower counts (≥105 CFU/L) may indicate UTI in symptomatic women, men, and those on antibiotics.
  • Mixed bacterial types or squamous epithelial cells indicate contamination.
  • Absence of pyuria makes acute cystitis unlikely.
• Urological Evaluation:
  • Required for men with recurrent UTIs or inadequate antibiotic response.
  • Not required for young healthy men with a single episode of uncomplicated cystitis and prompt antibiotic response.
• indwelling urinary catheters
  • Remove the indwelling catheter and obtain a midstream urine sample OR (if ongoing catheterisation is required)
  • Replace the catheter, then collect a urine sample from the port in the drainage system, or if this is not possible, by separating the catheter from the drainage system.
  • Do not collect a urine sample from the drainage bag for culture.
  • Ensure the pathology request clearly indicates that the urine sample provided for testing was obtained via a catheter.

Treatment of Acute Cystitis in Adults

• Nonantibiotic Therapy:
  • Analgesia: Offer paracetamol and nonsteroidal anti-inflammatory drugs.
  • Avoid:
    • Urinary alkalinising agents significantly reduce the antimicrobial effect of nitrofurantoin
    • Cranberry products, ascorbic acid, and methenamine hippurate are not effective.

• Empirical Antibiotic Therapy for Nonpregnant Women:
  • First-line:
    • Trimethoprim: 300 mg orally, daily for 3 days.
    • Nitrofurantoin: 100 mg orally, 6-hourly for 5 days (or 12-hourly for 5 days).
  • Alternative:
    • Cefalexin: 500 mg orally, 12-hourly for 5 days.
  • If Resistant:
    • Amoxicillin: 500 mg orally, 8-hourly for 5 days.
    • Trimethoprim + Sulfamethoxazole: 160+800 mg orally, 12-hourly for 3 days.
    • Amoxicillin + Clavulanate: 500+125 mg orally, 12-hourly for 5 days.
    • Fosfomycin: 3 g orally, single dose.
    • Norfloxacin: 400 mg orally, 12-hourly for 3 days.
    • Ciprofloxacin: 250 mg orally, 12-hourly for 3 days (reserve for resistant infections).
• Empirical Antibiotic Therapy for Men:
  • First-line:
    • Trimethoprim: 300 mg orally, daily for 7 days.
    • Nitrofurantoin: 100 mg orally, 6-hourly for 7 days.
  • Alternative:
    • Cefalexin: 500 mg orally, 12-hourly for 7 days.
  • If Resistant:
    • Amoxicillin: 500 mg orally, 8-hourly for 7 days.
    • Trimethoprim + Sulfamethoxazole: 160+800 mg orally, 12-hourly for 7 days.
    • Amoxicillin + Clavulanate: 500+125 mg orally, 12-hourly for 7 days.
    • Norfloxacin: 400 mg orally, 12-hourly for 7 days.
    • Ciprofloxacin: 250 mg orally, 12-hourly for 7 days.
    • Fosfomycin: Consult expert; limited evidence and dosage not well established.
• Post-treatment:
  • perform post-treatment urine culture for pregnant women and men with prostatitis.
• Notes
  • Trimethoprim: Avoid if used in the last 3 months or if E. coli resistant.
  • Nitrofurantoin: Avoid close to delivery due to risk of neonatal jaundice and hemolytic anemia.

Antibiotic Prophylaxis for Recurrent UTI

• Indications:
  • Consider prophylaxis for women with frequent symptomatic infections (two or more infections within 6 months, or three or more infections within 12 months).
  • Do not give prophylaxis for asymptomatic bacteriuria.
• Adverse Effects:
  • Common adverse effects include candidiasis.
  • Emergence of antibiotic-resistant organisms is common.
  • Long-term use of nitrofurantoin may cause rare adverse effects: pulmonary toxicity, hepatotoxicity, and peripheral polyneuropathy.
  • Monitor with regular spirometry, liver function, and kidney function tests.
• Non-Pharmacological:
  • Increasing Water Intake: Increasing water intake by up to 1.5 L daily may reduce the risk of recurrent UTI in premenopausal women with inadequate fluid intake (<1.5 L daily).
  • Intravaginal Estrogen:
    • Beneficial for postmenopausal women.
    • Improves vaginal flora and reduces incidence of recurrent UTI.
    • Supported by small randomized controlled trials.
    • See Intravaginal estrogen therapy for suitable regimens.
  • Cranberry Products: Not recommended for UTI prevention. Cranberry capsules did not reduce UTI incidence in elderly women in aged-care facilities.
  • Ascorbic Acid: Does not appear to be effective in preventing UTI.
  • Methenamine Hippurate: Evidence for prevention is poor and inconsistent.
    • May reduce symptomatic UTI in women without urinary tract abnormalities, but further research needed.
    • Not effective for UTI prevention in patients with urinary tract abnormalities.
• Pharmacological:
  • Continuous Prophylaxis:
    • Trimethoprim: 150 mg orally, at night.
    • Cefalexin: 250 mg orally, at night.
    • Nitrofurantoin: 50 mg orally, at night.
  • Intermittent Postcoital Prophylaxis:
    • A single dose of the antibiotics listed for continuous prophylaxis, taken within 2 hours after sexual intercourse.
  • Duration and Monitoring:
    • Typically used for 6 months, then stopped.
    • If UTIs recur despite prophylaxis, seek expert advice.
• Key Points
  • Do Not Use for Asymptomatic Bacteriuria: Antibiotic prophylaxis is not recommended for asymptomatic bacteriuria.
  • Alternative Approach: Patient-initiated treatment is an alternative to antibiotic prophylaxis.
  • Monitor for Adverse Effects: Regular monitoring for rare adverse effects, especially with nitrofurantoin, is crucial

Catheter-Associated UTI

• Pathogens: Similar to other UTIs: Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, Enterococcus species, Staphylococcus species, Candida species.
• Signs and Symptoms:
  • Fever (38°C or higher)
  • Rigors
  • Acute mental state change
  • Flank pain
  • Acute haematuria
  • Pelvic discomfort
• Investigation:
  • Do not investigate catheterized patients with nonspecific symptoms for CA-UTI.
  • Bacteriuria, pyuria, and cloudy or malodorous urine are not reliable signs in the absence of genitourinary symptoms.
  • Avoid inappropriate urinalysis or urine culture in asymptomatic patients to prevent misdiagnosis and overtreatment.
  • High incidence of bacteriuria with indwelling catheters (3-8% per day).
• Urine Sample Collection:
  • Remove the indwelling catheter and obtain a midstream urine sample.
  • If ongoing catheterization is required, replace the catheter and collect a sample from the port in the drainage system.
  • Do not collect urine samples from the drainage bag for culture.
  • Clearly indicate on the pathology request that the sample was obtained via a catheter.
• Absence of Pyuria:
  • In symptomatic catheterized patients, suggests a diagnosis other than UTI.
• Management – Guided by Culture: Use results of urine culture and susceptibility testing to guide antimicrobial therapy. Recommended duration of therapy is 7 days; extend to 10-14 days if response is delayed. for pseudomonas – Ciprofloxacin continues to be the preferred oral agent.
• Catheter Management: Antibiotic therapy is often transiently effective without catheter removal or replacement. Poor penetration of antibiotics into catheter biofilm can lead to superinfection with resistant organisms.

Prevention of Catheter-Associated UTI in Adults

• Limit Catheter Use:
  • Most effective strategy: limit use of indwelling urinary catheters.
  • Use catheters only when clearly indicated; remove them as soon as possible.
  • Use bladder ultrasound to avoid indwelling catheterization.
• Proper Technique:
  • Use sterile equipment and aseptic technique.
  • Maintain proper hygiene when handling and removing catheters.
  • Use a closed-catheter drainage system with ports for needle aspiration.
• Avoid Prophylaxis:
  • Do not use antibiotic prophylaxis to prevent CA-UTIs.
  • Antibiotic prophylaxis is not indicated at catheter placement, removal, or replacement.
  • Do not use instillations of antiseptic agents or irrigate the bladder with antimicrobial or antiseptic agents.

Acute Pyelonephritis

from eTG

• Definition: Kidney infection.
• Symptoms:
  • Flank pain
  • Nausea and vomiting
  • Fever (38°C or higher)
  • Costovertebral angle tenderness
• Associated Symptoms: May present with or without symptoms of acute cystitis (e.g., acute dysuria, frequency, urgency).
• Consider Prostatitis in Men: Particularly with fever (38°C or higher), obstructive urinary symptoms, or prostate tenderness on digital rectal examination.
• Investigations for Acute Pyelonephritis in Adults
  • Urine Sample: Obtain for culture and susceptibility testing before starting antibiotics.
  • Blood Samples: Collect for culture and susceptibility testing in hospitalized patients.
  • Microscopy: Diagnosis unlikely if pyuria is absent.
  • Imaging: Consider ultrasound to exclude urinary obstruction, kidney stone disease, or kidney abscess if the patient remains febrile after 72 hours of treatment.
  • Urological Evaluation: Required for men with acute pyelonephritis.
• Post-Treatment Culture:
  • Not required for asymptomatic patients, except for pregnant women and men with prostatitis.
• Treatment of Acute Pyelonephritis in Adults
  • Choice of Empirical Therapy:
  • Depends on disease severity and pregnancy status (see specific guidelines for pregnant women).
  • Initial Intravenous Therapy:
  • Required for patients with:
    • Inability to tolerate oral therapy
    • Fever (38°C or higher)
    • Systemic symptoms (e.g., tachycardia, nausea, vomiting)
    • Sepsis or septic shock
  • Oral Therapy for Nonsevere Pyelonephritis ( if the patient does not have fever (38°C or higher), systemic features (eg tachycardia, nausea, vomiting), or sepsis or septic shock):
    • Empirical Therapy:
      • Amoxicillin+Clavulanate: 875+125 mg orally, 12-hourly for 14 days (stop after 10 days if clinical response is rapid).
      • For penicillin hypersensitivity:
        • Ciprofloxacin: 500 mg orally, 12-hourly for 7 days.
    • Modify Based on Culture:
      • Switch to narrow-spectrum antibiotics if pathogen is susceptible:
        • Amoxicillin: 500 mg orally, 8-hourly for 14 days (stop after 10 days if clinical response is rapid).
        • Trimethoprim: 300 mg orally, daily for 14 days (stop after 10 days if clinical response is rapid).
        • Cefalexin: 500 mg orally, 6-hourly for 14 days (stop after 10 days if clinical response is rapid).
        • Trimethoprim+Sulfamethoxazole: 160+800 mg orally, 12-hourly for 14 days (stop after 10 days if clinical response is rapid).
      • If resistance confirmed or pathogen is Pseudomonas aeruginosa:
        • Ciprofloxacin: 500 mg orally, 12-hourly for 7 days.
    • Assess Response:
      • Within 24 to 48 hours; reconsider diagnosis if no improvement and culture results are unavailable.
  • Treatment of Severe Pyelonephritis( fever (38°C or higher), systemic symptoms (eg tachycardia, nausea, vomiting), or sepsis or septic shock):
    • Empirical Therapy:
      • Gentamicin intravenously
        • Plus either:
          • Amoxicillin: 2 g intravenously, 6-hourly.
          • Ampicillin: 2 g intravenously, 6-hourly.
      • If gentamicin is contraindicated:
        • Ceftriaxone: 1 g intravenously, daily.
        • Cefotaxime: 1 g intravenously, 8-hourly.
      • For penicillin hypersensitivity:
        • Use gentamicin as a single drug.
    • Modify Based on Culture:
      • Switch from gentamicin-containing regimen to ceftriaxone or cefotaxime if susceptibility results are unavailable by 72 hours.
  • Switch to Oral Therapy:
    • Once the patient is clinically stable.
    • Total therapy duration (IV + oral): 10 to 14 days (shorter course of 7 days for ciprofloxacin may be adequate).

Urethral Syndrome

• Definition: Dysuria and frequency without positive urine culture.
• Prevalence: Affects 30-40% of adult women with urinary symptoms.
• Possible Causes:
  • Bacterial cystitis with negative culture
  • Anaerobic organisms, fastidious organisms, ureaplasma, Chlamydia, viruses
  • Antiseptic contamination, residual antibiotics, spontaneous resolution of organism at culture

Interstitial Cystitis

• Definition: An uncommon but important cause of urethral syndrome.
• Symptoms: Frequency day and night, dull suprapubic ache relieved by bladder emptying.

Genitourinary Tuberculosis

• Prevalence: Involved in 3-5% of tuberculosis cases.
• Diagnosis: Routine culture shows sterile pyuria; need to culture mycobacterium in urine.

Candiduria

• Definition: Candida in urine.
• Management: Antifungal therapy not recommended if associated with an indwelling catheter.

Prostatitis

• Symptoms: Frequency, urgency, dysuria, flu-like illness, fever, low back ache, and perineal pain. Tender prostate on rectal examination.
• Management:
  • Mild to moderate infection: Same treatment as for cystitis.
  • Severe infection: Hospitalization for IV antibiotics.

UTI and Bacteriuria in Aged-Care Facility Residents

• Common Indication:
  • UTI is a common reason for antibiotic use in aged-care facilities.
  • Asymptomatic bacteriuria is common but should not be screened for or treated except in specific cases.
• Asymptomatic Bacteriuria:
  • Do not screen for or treat asymptomatic bacteriuria except in patients undergoing elective urological procedures.
  • Recurrent asymptomatic bacteriuria is not a UTI and does not require antibiotic therapy.
  • Overtreatment with antibiotics is common and contributes to antimicrobial resistance.
  • Stop antibiotic therapy if there is no benefit.

Assessment of UTI and Bacteriuria in Aged-Care Facility Residents

• Diagnosis:
  • Diagnosing symptomatic UTI is challenging due to the lack of validated criteria.
  • Mental status changes are often inappropriately used to start antibiotics.
  • Acute dysuria is the most specific symptom of symptomatic UTI in this population.
  • High prevalence of bacteriuria means urine culture is not helpful for nonspecific symptoms.
  • Cloudy or malodorous urine is not a reliable sign of UTI.
• Urine Investigation:
  • Do not investigate or treat cloudy or malodorous urine in the absence of other signs or symptoms of UTI.
  • Negative urinalysis (absence of both leukocyte esterase and nitrite) has a high negative predictive value for UTI.
  • Positive urinalysis has a low positive predictive value for UTI and is not an indication for antibiotics.

Initial Assessment and Management of Suspected UTI

• When UTI is Likely:
  • Obtain a urine sample for culture and susceptibility testing.
  • Higher risk of multidrug-resistant infections in this group.
  • Clean-catch or midstream urine samples may be difficult to obtain.
  • Consider using an in-out catheter for women or a new condom catheter for men as alternatives for urine sampling