When should Enterococcus faecium (E. faecium) in a urine culture be treated?

Treatment of Enterococcus faecium in Urine Cultures

Enterococcus faecium in urine cultures should only be treated when there is evidence of true urinary tract infection rather than colonization, with treatment decisions based on patient symptoms, risk factors, and clinical presentation.

Distinguishing Colonization from Infection

• It is crucial to differentiate between colonization and true infection before initiating antimicrobial therapy for Enterococcus faecium in urine cultures 1
• Asymptomatic bacteriuria with Enterococcus species, including E. faecium, generally should not be treated, particularly in patients with indwelling catheters 2
• Routine treatment of asymptomatic bacteriuria with multidrug-resistant Enterococcus is not recommended 2

Indications for Treatment

Treat E. faecium in urine cultures when:

• Patient presents with symptoms of urinary tract infection (dysuria, frequency, urgency, suprapubic pain) 1
• Systemic signs of infection are present (fever, rigors, altered mental status, flank pain) 1
• Patient has risk factors for complicated infection along with symptoms 1
• Bacteremia is present or suspected 3
• Patient is immunocompromised with symptoms of UTI 1

Do not treat E. faecium in urine cultures when:

• Patient is asymptomatic (asymptomatic bacteriuria) 1
• Patient has an indwelling catheter without signs of systemic infection 1
• Urine culture represents colonization rather than infection 1
• In renal transplant recipients >1 month after surgery without symptoms (treatment does not prevent pyelonephritis or improve graft function) 1

Risk Factors That May Influence Treatment Decision

• Healthcare-associated infections 1
• Presence of urological abnormalities or foreign bodies 1
• Recent history of instrumentation 1
• Incomplete voiding 1
• Obstruction at any site in the urinary tract 1
• Immunosuppression 1
• Diabetes mellitus 1
• Male gender (UTIs in males are considered complicated) 1
• Multidrug-resistant organisms isolated 1

Treatment Approach for Symptomatic E. faecium UTI

For uncomplicated lower UTI (cystitis):

• Nitrofurantoin is an appropriate oral option if the isolate is susceptible 2, 4
• Fosfomycin may be considered for uncomplicated lower UTI caused by susceptible strains 2, 5
• Doxycycline can be considered if the isolate is susceptible 2

For complicated UTI or pyelonephritis:

• Ampicillin is the drug of choice if the isolate is susceptible, even for ampicillin-resistant VRE in urinary tract infections due to high urinary concentrations 1
• For ampicillin-resistant strains, options include:
  • Linezolid for confirmed upper and/or bacteremic VRE UTIs 3
  • Daptomycin for complicated UTIs with susceptible strains 6
  • Combination therapy may be considered for severe infections 1

For vancomycin-resistant E. faecium (VRE):

• Linezolid is recommended for upper tract and/or bacteremic VRE UTIs 3
• Daptomycin has shown efficacy in treating complicated UTIs caused by VRE 6
• Nitrofurantoin or fosfomycin may be considered for lower tract VRE UTIs (cystitis) 2, 3

Duration of Therapy

• For uncomplicated lower UTI: 5-7 days 1
• For complicated UTI: 7-14 days 1
• For men when prostatitis cannot be excluded: 14 days 1
• Duration should be related to treatment of any underlying abnormality 1
• When the patient is hemodynamically stable and afebrile for at least 48 hours, shorter treatment duration (7 days) may be considered 1

Special Considerations

• Remove indwelling urinary catheters when possible to facilitate treatment 2
• Appropriate management of any underlying urological abnormality is mandatory 1
• Urine culture and susceptibility testing should guide definitive therapy 1
• Initial empiric therapy should be tailored once culture results are available 1
• High-dose ampicillin (18-30g IV daily) or amoxicillin (500mg PO/IV every 8h) may overcome resistance in urinary tract infections due to high urinary concentrations 1

Monitoring and Follow-up

• Clinical response should be assessed within 48-72 hours of initiating therapy 1
• Follow-up urine cultures are generally not necessary if symptoms resolve 1
• For recurrent or persistent symptoms, repeat urine culture and susceptibility testing 1
• Consider urological evaluation for patients with recurrent infections or treatment failures 1