Is Tazocin (piperacillin/tazobactam) effective for treating Enterococcus faecalis urinary tract infections (UTIs)?

Effectiveness of Tazocin (Piperacillin/Tazobactam) for Enterococcus faecalis UTIs

Tazocin (piperacillin/tazobactam) is effective against Enterococcus faecalis urinary tract infections and can be used as a treatment option for severe UTIs caused by this pathogen. 1, 2

Antimicrobial Activity Against E. faecalis

E. faecalis is generally susceptible to piperacillin/tazobactam, unlike E. faecium which is typically resistant to this combination. This important distinction makes proper identification of the enterococcal species crucial for treatment decisions:

• E. faecalis is susceptible to ampicillin and piperacillin/tazobactam 3
• E. faecium is generally resistant to both ampicillin and piperacillin/tazobactam 3

In vitro studies have demonstrated that tazobactam effectively reverses beta-lactamase-mediated resistance in E. faecalis, maintaining activity even against beta-lactamase-producing strains 2. The addition of tazobactam to piperacillin significantly reduces the inoculum effect seen with piperacillin alone against these strains.

Treatment Recommendations for E. faecalis UTIs

According to guidelines and clinical evidence:

• First-line options for E. faecalis UTIs:

  • Amoxicillin-clavulanic acid 500/125 mg orally three times daily for 7 days 1
  • Ampicillin/sulbactam (for ciprofloxacin-resistant strains) 4

• For severe infections requiring parenteral therapy:

  • Piperacillin/tazobactam is recommended as an effective option for severe UTIs 5, 6
  • Clinical studies have shown favorable response rates of over 80% when using piperacillin/tazobactam for complicated UTIs, including those caused by Enterococcus species 7

Clinical Application and Considerations

When treating E. faecalis UTIs with piperacillin/tazobactam:

1. Dosing: Standard dosing of 4g/500mg IV every 6-8 hours is typically used for severe UTIs
2. Duration: 7-10 days for complicated UTIs 1
3. Monitoring: Regular assessment of clinical response and follow-up urine cultures may be necessary

Important Caveats and Considerations

• Fluoroquinolone resistance: High rates of fluoroquinolone resistance (approximately 47% for ciprofloxacin) have been observed in E. faecalis strains, making these agents less reliable for empiric therapy 4

• Risk of selecting for resistant organisms: Prolonged or repeated use of piperacillin/tazobactam has been associated with an increased risk of E. faecium bacteremia, which is inherently resistant to this agent 3

• Alternative options for resistant strains: For multidrug-resistant strains, consider:

  • Fosfomycin (if susceptible)
  • Nitrofurantoin (if susceptible)
  • Carbapenems for severe infections 1

• Synergistic combinations: For severe, invasive infections, combining piperacillin/tazobactam with an aminoglycoside may provide synergistic activity against E. faecalis 2

In conclusion, piperacillin/tazobactam (Tazocin) is an effective treatment option for E. faecalis UTIs, particularly in severe or complicated cases requiring parenteral therapy. However, antimicrobial susceptibility testing should always guide the final selection of antimicrobial agents to ensure optimal treatment outcomes.