Urinary Tract Infections: Treatment and Prevention

• Urinary tract infections (UTIs) are common outpatient infections.
• The most common pathogen causing a UTI is Escherichia coli.

UTI Causes

• Escherichia coli causes 75% of cases without urinary tract structural abnormalities or stones.
• Escherichia coli causes 65% of complicated UTIs.
• Fungal and parasitic infections can cause UTIs, especially in those immunosuppressed, with diabetes or kidney problems, or after multiple antibiotic courses.

Classification of UTI

• UTIs are classified as upper or lower, depending on the location in the urinary system.
• Pyelonephritis is inflammation of the renal parenchyma and collecting system.
• Cystitis is inflammation of the bladder.
• Urethritis is inflammation of the urethra.
• Urosepsis is a life-threatening UTI that has spread systemically and requires emergency treatment.
• UTIs are classified as complicated or uncomplicated.
• Uncomplicated UTIs occur in a normal urinary tract and usually involve only the bladder.
• Complicated UTIs occur in individuals with underlying diseases or structural/functional urinary tract problems.
  • Examples include obstruction, stones, catheters, abnormal genitourinary tract, acute kidney injury, chronic kidney disease, kidney transplant, diabetes, neurologic disease, antibiotic resistance, immunocompromised status, pregnancy-induced changes, or recurrent infection.
• Individuals with complicated infections are at risk for pyelonephritis, urosepsis, and renal damage.

Etiology and Pathophysiology

• The urinary tract above the urethra is normally sterile.
• Mechanical and physiologic defense mechanisms maintain sterility, including:
  • Normal voiding with complete bladder emptying.
  • Ureterovesical junction competence.
  • Ureteral peristaltic activity.
• Urine's antibacterial properties are due to a slightly acidic pH (6.0 to 7.5) and antimicrobial proteins/peptides.
• Organisms causing UTIs originate in the perineum and ascend via the urethra.
• Most infections are caused by gram-negative bacilli from the GI tract.
• Gram-positive organisms like streptococci, enterococci, and Staphylococcus saprophyticus can also cause UTIs.
• Urologic instrumentation (e.g., catheterization, cystoscopy) is a common factor in ascending infections.
• Sexual intercourse can promote bacteria movement from the vagina and perineum.
• UTIs can result from hematogenous transmission, where blood-borne bacteria invade the kidneys, ureters, or bladder.
• Kidney infections via hematogenous transmission typically require prior urinary tract injury.
• UTIs are the most common health care–associated infection (HAI), mainly due to indwelling catheters.
• Catheter-associated urinary tract infections (CAUTIs) are often caused by E. coli and Pseudomonas organisms.
• CAUTIs increase hospital stays, health care costs, and mortality.

Common Causes of UTIs

• Candida species
• Enterobacter
• Enterococcus
• Escherichia coli
• Klebsiella pneumoniae
• Proteus mirabilis
• Pseudomonas aeruginosa
• Serratia
• Staphylococcus aureus
• Streptococci, Group B.

Anatomic Factors

• Congenital defects causing obstruction or urinary stasis
• Fistulas exposing the urinary stream
• Obesity
• Shorter female urethra and colonization from normal vaginal flora

Factors Compromising Immune Response

• Aging
• Diabetes
• HIV infection

Factors Increasing Urinary Stasis

• Extrinsic obstruction (tumor, fibrosis)
• Intrinsic obstruction (stone, tumor, urethral stricture, BPH)
• Renal impairment
• Urinary retention (e.g., neurogenic bladder)

Foreign Bodies

• Catheters and other urinary tract instrumentation and stones

Functional Disorders

• Constipation
• Voiding dysfunction

Clinical Manifestations

• Symptoms range from painful urination to severe systemic illness with abdominal/back pain, fever, and sepsis.
• Lower urinary tract symptoms (LUTS) include dysuria, frequency (voiding more than every 2 hours), urgency, and suprapubic discomfort/pressure.
• Urine may contain visible blood (hematuria) or sediment, making it appear cloudy.
• Upper UTIs typically cause fever, chills, and flank pain, whereas lower UTIs usually lack systemic manifestations.
• Significant bacteriuria may present with no symptoms or nonspecific symptoms like fatigue or anorexia.
• Older adults may have atypical symptoms such as general abdominal discomfort, impaired cognition, or clinical deterioration, rather than typical UTI symptoms.
• Temperature is an unreliable sign of a UTI in older adults.
• Bladder tumors, intravesical chemotherapy, or pelvic radiation can produce LUTS similar to UTI symptoms.
• Asymptomatic bacteriuria, the presence of bacteria in the bladder without symptoms, doesn't justify treatment except in pregnant women, recent kidney transplant recipients, or those undergoing urologic procedures.

Diagnostic Studies

• First, obtain a dipstick urinalysis to identify nitrites, white blood cells (WBCs), and leukocyte esterase.
• Microscopic urinalysis can confirm these findings.
• Bacterial counts of 105 colony-forming units per milliliter (CFU/mL) or higher typically indicate a clinically significant UTI.
• Counts as low as 102 to 103 CFU/mL in symptomatic individuals can be indicative of a UTI.
• A urine culture is needed in persistent bacteriuria, recurring UTIs, complicated UTIs, CAUTIs, or HAIs.
• A urine culture is needed when the infection doesn't respond to empiric therapy or the diagnosis is questionable.
• A voided midstream technique (clean-catch urine sample) is best for obtaining a urine culture.
• Catheterization gives more accurate results when a clean-catch specimen can't be obtained.
• Urine culture with sensitivity testing determines the bacteria’s susceptibility to antibiotics.
• Ultrasound or CT scans may be done if obstruction is suspected or UTIs recur.

Interprofessional Care

• Appropriate antimicrobial therapy is started once a UTI is diagnosed, either empirically or based on sensitivity testing.
• Uncomplicated UTIs are treated with short-term antibiotics, typically for 3 days.
• Complicated UTIs need longer treatment, lasting 7 to 14 days or more.
• Only treat symptomatic UTIs in residents of long-term care facilities, especially women, who often have chronic asymptomatic bacteriuria.

Drug Therapy

• First-choice drugs for uncomplicated UTIs are trimethoprim/sulfamethoxazole (TMP/SMX), nitrofurantoin, cephalexin, and fosfomycin.
• Fluoroquinolones (e.g., levofloxacin, ciprofloxacin) are given to treat complicated UTIs.
• Fluconazole treats fungal UTIs.
• Oral phenazopyridine may relieve discomfort from severe dysuria but turns urine orange or red.
• Prophylactic antibiotics, such as low-dose TMP/SMX or nitrofurantoin, may prevent recurring UTIs, but long-term use is limited due to antibiotic resistance.

Nursing Management: Urinary Tract Infection

• Clinical problems for a patient with a UTI may include impaired urinary elimination, infection, pain, and deficient knowledge.
• Overall goals for a patient with a UTI are relief from bothersome symptoms, no upper urinary tract involvement, and no recurrence.

Implementation

• Health promotion measures can help decrease the frequency of UTIs and support early detection of infection in at-risk populations.
• Preventive measures include emptying the bladder regularly and completely, evacuating the bowel regularly, wiping the perineal area from front to back, and drinking adequate liquids.

Prevention of CAUTI

• Avoiding unnecessary catheterization and early removal of indwelling catheters are the most effective means for reducing CAUTI.
• Fluid intake may be hard because the patient feeling that fluid intake will make the pain and urinary frequency worse.
• Adequate fluid intake is crucial unless contraindicated, as it dilutes urine and flushes out bacteria.
• Avoid caffeine, alcohol, citrus juices, chocolate, and highly spiced foods because they are bladder irritants.
• Applying heat to the suprapubic area or lower back may relieve discomfort.
• Emphasize the importance of taking the full course of antibiotics.

Ambulatory Care

• Teach the patient and caregiver about the need for ongoing care, including taking antimicrobial drugs as ordered, maintaining adequate daily fluid intake, voiding regularly (every 3 to 4 hours), and voiding before and after intercourse.

Evaluation

• The expected outcomes are that the patient with a UTI will have normal urinary elimination patterns, report relief of bothersome urinary tract symptoms, and state knowledge of the treatment plan.

Diagnostic Assessment

• History and physical assessment is key
• Urinalysis (midstream, “clean-catch” voided specimen) is helpful
• Urine for culture and sensitivity (if indicated) is useful
• Imaging studies of urinary tract (if indicated): CT scan, ultrasound, cystoscopy are all options

Management

• Patient teaching is essential
• Adequate fluid intake (8 to 9 8-oz glasses/day) is critical for uncomplicated and recurrent UTI

Drug Therapy

• Antibiotics
• Fluconazole (in patients with fungal UTI)
• Fosfomycin (Monurol)
• Nitrofurantoin (Macrodantin, Macrobid)
• TMP/SMX (Bactrim, Bactrim DS)
• Trimethoprim alone (in patients with sulfa allergy)
• Cephalexin

Recurrent UTI

• Repeat urinalysis
• Urine culture and sensitivity testing
• Adequate fluid intake (8 to 9 8-oz glasses/day)
• Imaging studies of urinary tract (if indicated)

Drug Therapy for Recurrent UTI

• Sensitivity-guided antibiotic therapy: ampicillin, amoxicillin, 1st- or 2nd-generation cephalosporin, fluoroquinolones
• 3- to 6-month trial of suppressive or prophylactic antibiotic therapy
• Antibiotic: nitrofurantoin, TMP/SMX
• Postcoital antibiotic prophylaxis: cephalexin, nitrofurantoin, TMP/SMX, fosfomycin, trimethoprim