From the Guidelines
Yes, Zosyn (piperacillin/tazobactam) does cover Pseudomonas aeruginosa, as it is listed as an antipseudomonal β-lactam suitable for treatment of P. aeruginosa pneumonia 1. This combination antibiotic is effective against many Pseudomonas aeruginosa strains, making it a valuable option for treating infections caused by this organism. Zosyn combines piperacillin, an extended-spectrum penicillin, with tazobactam, a beta-lactamase inhibitor that prevents bacterial enzymes from inactivating the piperacillin component. The typical adult dosing for serious Pseudomonas infections is 4.5 grams (4 g piperacillin/0.5 g tazobactam) administered intravenously every 6-8 hours, with adjustments needed for patients with renal impairment. Some key points to consider when using Zosyn for Pseudomonas infections include:
- Obtaining cultures and susceptibility testing to confirm the specific Pseudomonas strain is susceptible to Zosyn 1
- Considering combination therapy with another anti-pseudomonal agent in cases of severe infection until susceptibilities are known 1
- Being aware of the potential for resistance, particularly in healthcare settings with high antibiotic use or in patients with previous Pseudomonas infections
- Following recommended treatment durations, which can range from 5-14 days depending on the type of infection and individual patient factors 1
From the FDA Drug Label
PIPRACIL is indicated for the treatment of serious infections caused by susceptible strains of the designated microorganisms in the conditions listed below: Intra-Abdominal Infections including hepatobiliary and surgical infections caused by E. coli, Pseudomonas aeruginosa, enterococci, Clostridium spp., anaerobic cocci, or Bacteroides spp., including B. fragilis.
For testing Pseudomonas aeruginosa: MIC (μg/mL) Interpretation ≤ 64 ≥ 128 Susceptible (S) Resistant (R)
Zosyn covers Pseudomonas aeruginosa. The drug label indicates that piperacillin/tazobactam is active against Pseudomonas aeruginosa and is indicated for the treatment of serious infections caused by this microorganism 2. The susceptibility criteria for Pseudomonas aeruginosa are also provided, with an MIC of ≤ 64 μg/mL indicating susceptibility 2.
From the Research
Zosyn Coverage of Pseudomonas
- Zosyn, also known as piperacillin/tazobactam, is an antibiotic used to treat various bacterial infections, including those caused by Pseudomonas aeruginosa 3, 4, 5, 6.
- The effectiveness of Zosyn against Pseudomonas aeruginosa depends on the dosing regimen and the susceptibility of the bacteria to the antibiotic 4, 5, 6.
- Studies have shown that extended-infusion or continuous-infusion dosing regimens of Zosyn can improve the probability of achieving adequate drug exposure against Pseudomonas aeruginosa 3, 4, 6.
- The Clinical and Laboratory Standards Institute (CLSI) has established breakpoints for the susceptibility of Pseudomonas aeruginosa to Zosyn, and doses of 3.375 g q6h as 0.5-hour infusion or 4.5 g q8h as a 4-hour infusion may be adequate for susceptible strains 5.
- However, for carbapenem-resistant Pseudomonas aeruginosa, higher doses and extended infusion regimens may be necessary to optimize exposure 5.
Factors Affecting Zosyn Efficacy
- The efficacy of Zosyn against Pseudomonas aeruginosa can be affected by various factors, including the MIC of the bacteria, the dosing regimen, and the patient's renal function 4, 5, 6.
- Prior exposure to antibiotics, including Zosyn, can also increase the risk of developing resistance to the antibiotic 7.
- The selection of an appropriate dosing regimen and the monitoring of antibiotic resistance patterns are crucial to ensuring the effective use of Zosyn against Pseudomonas aeruginosa infections 3, 4, 5, 6, 7.