What is the recommended treatment for a male patient with a urinary tract infection (UTI) caused by Enterococcus faecalis?

Treatment of Enterococcus faecalis UTI in Male Patients

For male patients with UTI caused by Enterococcus faecalis, amoxicillin 500 mg orally every 8 hours for 7-14 days is the first-line treatment, with the longer duration (14 days) recommended when prostatitis cannot be excluded. 1, 2, 3

Initial Management Approach

All male UTIs are classified as complicated UTIs by definition, requiring more aggressive treatment than uncomplicated cystitis in women. 1 This classification is critical because:

• Male anatomy predisposes to prostatic involvement that may not be clinically apparent 1
• Treatment duration must account for potential prostatic infection (14 days vs 7 days) 1
• Urine culture and susceptibility testing are mandatory before initiating therapy 1, 2, 3

First-Line Treatment Options

Oral Therapy (Outpatient or Step-Down)

Amoxicillin/Ampicillin remains the drug of choice despite what in vitro susceptibility testing may suggest, because high urinary concentrations can overcome elevated MICs: 2, 3

• Amoxicillin 500 mg orally every 8 hours achieves 88.1% clinical and 86% microbiological eradication rates 2, 3
• Ampicillin 500 mg orally every 8 hours is an equivalent alternative 2, 3
• Duration: 7 days minimum, 14 days when prostatitis cannot be excluded 1

Intravenous Therapy (Hospitalized Patients)

For patients requiring hospitalization due to systemic symptoms or inability to tolerate oral therapy: 1

• High-dose ampicillin 18-30 g IV daily in divided doses (typically 2 g IV every 4 hours) 2, 3
• Amoxicillin 500 mg IV every 8 hours as an alternative 2
• Combination therapy with aminoglycoside (amoxicillin plus aminoglycoside) for severe presentations with systemic symptoms 1

Alternative Oral Agents

When beta-lactams cannot be used or for specific clinical scenarios:

Nitrofurantoin

• Dosing: 100 mg orally every 6 hours for 7 days 2, 3
• Resistance rates below 6% against E. faecalis 2, 4
• Critical contraindications: Do NOT use if creatinine clearance <60 mL/min, for pyelonephritis, or when prostatitis is suspected (achieves poor tissue/serum concentrations) 2

Fosfomycin

• Dosing: 3 g orally as a single dose 2, 3
• FDA-approved specifically for E. faecalis UTI 2, 3
• Best reserved for uncomplicated lower tract infections when 14-day therapy is not indicated 2, 3

Agents to AVOID

Fluoroquinolones (ciprofloxacin, levofloxacin) should NOT be used empirically for several compelling reasons: 1, 5, 6

• Resistance rates of 46-47% in E. faecalis from male UTIs 2, 5, 6
• Resistance increases with age: 22% in men 18-29 years to 37% in men ≥70 years 6
• Only consider if local resistance <10% AND patient has anaphylaxis to beta-lactams 1
• Do NOT use if patient is from urology department or used fluoroquinolones in last 6 months 1

Treatment Algorithm by Clinical Scenario

Mild-Moderate Symptoms (Outpatient)

1. Obtain urine culture and susceptibility testing 1, 2
2. Start amoxicillin 500 mg PO every 8 hours 2, 3
3. Treat for 14 days (prostatitis cannot be excluded in males) 1
4. Adjust based on culture results 1

Severe Symptoms or Hospitalized

1. Obtain urine culture and blood cultures 1
2. Start amoxicillin plus aminoglycoside IV or ampicillin 2 g IV every 4 hours 1, 3
3. Transition to oral amoxicillin when afebrile ≥48 hours and hemodynamically stable 1
4. Complete 14 days total (7 days may be considered if definitively not prostatitis and patient stable) 1

Penicillin Allergy

1. Nitrofurantoin 100 mg PO every 6 hours for 7-14 days (if CrCl >60 mL/min and lower tract only) 2, 3
2. For severe allergy or complicated infection: Consider vancomycin or linezolid based on susceptibility 1

Vancomycin-Resistant E. faecalis (VRE)

• Fosfomycin 3 g single dose for uncomplicated lower tract 1, 3
• Nitrofurantoin 100 mg PO every 6 hours for uncomplicated lower tract 1, 3
• High-dose ampicillin may still be effective due to high urinary concentrations 1, 2
• Linezolid 600 mg IV/PO every 12 hours for complicated infections 1

Critical Clinical Pitfalls

Always confirm susceptibility testing even for "pansensitive" strains, as resistance patterns vary significantly by institution and patient population. 2, 3

Differentiate colonization from true infection - asymptomatic bacteriuria with E. faecalis does not require treatment. 7 Look for:

• Dysuria, frequency, urgency 1
• Fever, flank pain, costovertebral angle tenderness 1
• Systemic symptoms (rigors, altered mental status in elderly) 1

E. faecalis is the second most common pathogen in male UTIs (16%) and is particularly common in young men (17%) and polymicrobial infections (47%). 6 This high prevalence means empiric coverage should account for enterococcal pathogens in males.

Recurrence rates are higher with E. faecalis (26%) compared to E. coli (22%), increasing from 12% in men 18-29 years to 28% in men ≥70 years. 6 This emphasizes the importance of adequate initial treatment duration and follow-up.

Hospital-acquired infections have 18-fold increased risk of ciprofloxacin resistance (OR 18.15), making beta-lactams even more critical in nosocomial settings. 5