From the Guidelines
Tazobactam and avibactam are both beta-lactamase inhibitors used in combination with antibiotics to overcome bacterial resistance, but they differ significantly in their spectrum of activity and chemical structure. Tazobactam is a penicillanic acid sulfone that primarily inhibits class A beta-lactamases (including extended-spectrum beta-lactamases or ESBLs) and some class C enzymes, as seen in studies such as 1. It's commonly paired with piperacillin (as Zosyn) to treat various infections including intra-abdominal infections, pneumonia, and complicated urinary tract infections. In contrast, avibactam is a newer diazabicyclooctane non-beta-lactam inhibitor with broader activity against class A, class C, and some class D beta-lactamases, including carbapenemases like KPC, as noted in 1. Avibactam is paired with ceftazidime (as Avycaz) to treat serious gram-negative infections, including those resistant to other antibiotics. This broader spectrum makes avibactam-containing combinations effective against more resistant organisms than tazobactam combinations, particularly for treating carbapenem-resistant Enterobacterales. Some key points to consider when choosing between these agents include:
- The suspected pathogens and local resistance patterns, as discussed in 1
- The specific infection being treated, such as intra-abdominal infections or diabetic foot infections, as seen in 1
- The potential for resistance and the need to preserve the activity of certain antibiotic classes, as noted in 1 The choice between tazobactam and avibactam should be based on the individual patient's needs and the specific clinical scenario, with consideration of the most recent and highest quality evidence, such as the study by 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Comparison of Tazobactam (TZB) and Avibactam (AVI)
- Tazobactam and Avibactam are both β-lactamase inhibitors used in combination with antibiotics to treat multidrug-resistant gram-negative bacterial infections 2, 3.
- Avibactam has increased potency and an expanded spectrum of inhibition of class A and C β-lactamases, including extended-spectrum β-lactamases, AmpC, and Klebsiella pneumoniae carbapenemase (KPC) enzymes 3.
- Tazobactam is used in combination with ceftolozane, while Avibactam is used in combination with ceftazidime 2, 3.
- Both combinations have shown effectiveness against multidrug-resistant Pseudomonas aeruginosa and extended-spectrum β-lactamase-producing Enterobacterales 4, 5.
- A study comparing the effectiveness of ceftolozane-tazobactam and ceftazidime-avibactam for multidrug-resistant Pseudomonas aeruginosa infections found that ceftolozane-tazobactam resulted in higher rates of clinical success, particularly for patients with pneumonia 6.
Spectrum of Activity
- Avibactam does not inactivate metallo-β-lactamases, such as New Delhi metallo-β-lactamases 2.
- Ceftazidime-avibactam has good in vitro activity against Pseudomonas aeruginosa, comparable to amikacin and ceftolozane-tazobactam 4.
- Ceftolozane-tazobactam and ceftazidime-avibactam have similar activity against extended-spectrum β-lactamase-producing Enterobacterales, but ceftolozane-tazobactam may have improved activity against Pseudomonas aeruginosa 5.
Clinical Use
- Both ceftolozane-tazobactam and ceftazidime-avibactam are only available as intravenous formulations and are dosed 3 times daily in patients with normal renal function 2.
- Clinical trials have shown noninferiority of both agents compared to comparators for the treatment of complicated urinary tract infections and complicated intra-abdominal infections 2, 3.
- Ceftazidime-avibactam has received FDA approval for the treatment of complicated urinary tract infections, including pyelonephritis, and complicated intra-abdominal infections, in combination with metronidazole, in adult patients with limited or no alternative treatment options 3.