Does Zosyn (piperacillin/tazobactam) cover Staphylococcus aureus methicillin-sensitive (MSSA)?

From the Guidelines

Yes, Zosyn (piperacillin-tazobactam) effectively covers methicillin-sensitive Staphylococcus aureus (MSSA). Zosyn is a combination antibiotic containing piperacillin, an extended-spectrum penicillin, and tazobactam, a beta-lactamase inhibitor. The standard dosing for adults with normal renal function is typically 3.375g or 4.5g IV every 6 hours, with dose adjustments needed for patients with impaired kidney function. Zosyn works by inhibiting bacterial cell wall synthesis and is active against many gram-positive organisms including MSSA, as well as numerous gram-negative and anaerobic bacteria. This broad spectrum makes it useful for empiric therapy in many serious infections. According to the guidelines for the management of adults with hospital-acquired and ventilator-associated pneumonia 1, Zosyn is recommended as an initial empiric antibiotic therapy for hospital-acquired pneumonia, which includes coverage for MSSA. However, it's essential to note that while Zosyn covers MSSA, it does not cover methicillin-resistant Staphylococcus aureus (MRSA). For known MSSA infections, narrower spectrum options like nafcillin, oxacillin, or cefazolin are often preferred when possible to reduce the risk of antimicrobial resistance and potential side effects.

Some key points to consider when using Zosyn for MSSA coverage include:

• The importance of dose adjustments in patients with impaired renal function
• The need for careful consideration of potential side effects and antimicrobial resistance
• The recommendation for narrower spectrum options for known MSSA infections
• The utility of Zosyn in empiric therapy for serious infections, as outlined in the guidelines for hospital-acquired pneumonia 1.

It's also worth noting that other guidelines, such as those for the diagnosis and management of skin and soft tissue infections 1, may provide additional context and recommendations for the use of Zosyn in various clinical scenarios. However, the most recent and highest quality study, as represented by the 2016 guidelines for hospital-acquired pneumonia 1, should take precedence in guiding clinical decision-making.

From the FDA Drug Label

1. 2 Nosocomial Pneumonia Piperacillin and tazobactam for injection, USP is indicated in adults and pediatric patients (2 months of age and older) for the treatment of nosocomial pneumonia (moderate to severe) caused by beta-lactamase producing isolates of Staphylococcus aureus and by piperacillin and tazobactam-susceptible Acinetobacter baumannii, Haemophilus influenzae, Klebsiella pneumoniae, and Pseudomonas aeruginosa
2. 3 Skin and Skin Structure Infections Piperacillin and tazobactam for injection, USP is indicated in adults for the treatment of uncomplicated and complicated skin and skin structure infections, including cellulitis, cutaneous abscesses and ischemic/diabetic foot infections caused by beta-lactamase producing isolates of Staphylococcus aureus.

Zosyn (piperacillin/tazobactam) covers Staphylococcus aureus, including methicillin-sensitive strains, as indicated for the treatment of nosocomial pneumonia and skin and skin structure infections caused by beta-lactamase producing isolates of Staphylococcus aureus 2 2.

• Key points:
  • Zosyn is effective against beta-lactamase producing isolates of Staphylococcus aureus.
  • Methicillin-sensitive Staphylococcus aureus is typically susceptible to beta-lactam antibiotics, such as piperacillin.

From the Research

Zosyn Coverage for Staph Aureus Methicillin Sensitive

• Zosyn, also known as piperacillin/tazobactam, is a broad-spectrum antibiotic used to treat various bacterial infections, including those caused by Staphylococcus aureus.
• According to the study 3, piperacillin/tazobactam is not as effective as nafcillin/oxacillin or cefazolin in treating methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia.
• Another study 4 recommends using cefazolin or antistaphylococcal penicillins for MSSA, while vancomycin or daptomycin is recommended for methicillin-resistant Staphylococcus aureus (MRSA).
• The study 5 found no difference in treatment success with cefepime, meropenem, or piperacillin-tazobactam for polymicrobial infections with one offending organism being MSSA.
• However, the study 6 found that piperacillin-tazobactam and cefuroxime had comparable effectiveness as empirical therapy for MSSA bacteremia.
• In vitro studies 7 have shown that meropenem/piperacillin/tazobactam triple combination therapy has activity against clinical isolates of Staphylococcus aureus, including MRSA and MSSA.

Key Findings

• Piperacillin/tazobactam may not be the most effective treatment option for MSSA bacteremia compared to other antibiotics like nafcillin/oxacillin or cefazolin 3.
• Cefazolin or antistaphylococcal penicillins are recommended for MSSA, while vancomycin or daptomycin is recommended for MRSA 4.
• Piperacillin-tazobactam and cefuroxime have comparable effectiveness as empirical therapy for MSSA bacteremia 6.
• Meropenem/piperacillin/tazobactam triple combination therapy has activity against clinical isolates of Staphylococcus aureus, including MRSA and MSSA 7.