Is Zosyn (piperacillin/tazobactam) effective against anaerobic bacteria?

From the Guidelines

Yes, Zosyn (piperacillin/tazobactam) is effective against anaerobic bacteria.

Key Points

• The antibiotic regimen for infected necrosis should cover both aerobic and anaerobic Gram-negative and Gram-positive microorganisms 1.
• Piperacillin/tazobactam is specifically mentioned as being effective against gram-positive bacteria and anaerobes, making it a suitable choice for treating anaerobic infections 1.
• Other antibiotics, such as quinolones and carbapenems, also have good anaerobic coverage, but their use may be limited due to resistance concerns or reserved for critically ill patients 1.
• Metronidazole is another option with good penetration into the pancreas and a bactericidal spectrum focused against anaerobes, but its use is more limited to specific cases 1.

Rationale

The effectiveness of Zosyn against anaerobic bacteria is supported by its inclusion in the recommended antibiotic regimens for infected necrosis, which should cover a broad spectrum of microorganisms, including anaerobes 1. The fact that piperacillin/tazobactam is specifically mentioned as being effective against anaerobes, in addition to gram-positive bacteria, makes it a suitable choice for treating anaerobic infections.

From the FDA Drug Label

Piperacillin and tazobactam has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections... Anaerobic bacteria Bacteroides fragilis group (B. fragilis, B. ovatus, B. thetaiotaomicron, and B. vulgatus)

Zosyn (piperacillin/tazobactam) is effective against certain anaerobic bacteria, including the Bacteroides fragilis group. 2

From the Research

Effectiveness of Zosyn (Piperacillin/Tazobactam) Against Anaerobic Bacteria

• Zosyn (piperacillin/tazobactam) has been shown to be effective against anaerobic bacteria in several studies 3, 4, 5, 6, 7.
• The combination of piperacillin and tazobactam has a broad spectrum of antibacterial activity that includes Gram-positive and Gram-negative aerobic and anaerobic bacteria 3, 4, 5, 6.
• Studies have demonstrated that piperacillin/tazobactam is effective against a wide range of anaerobic isolates, including those that produce beta-lactamases 4, 7.
• The antimicrobial activity of piperacillin is enhanced by the addition of tazobactam against Gram-positive, Gram-negative, and anaerobic bacteria 4.
• Piperacillin/tazobactam has been shown to be as effective as other antibiotics, such as imipenem/cilastatin and ticarcillin/clavulanate, in the treatment of infections caused by anaerobic bacteria 6, 7.

Spectrum of Activity

• Piperacillin/tazobactam has a wide spectrum of activity that includes:
  • Gram-positive organisms such as staphylococci and streptococci 5
  • Gram-negative aerobic and anaerobic bacteria, including many pathogens that produce beta-lactamases 3, 4, 6
  • Anaerobic isolates, including Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, and Streptococcus pneumoniae 7

Clinical Efficacy

• Piperacillin/tazobactam has been shown to be clinically effective in the treatment of a variety of infections, including:
  • Intra-abdominal infections 3, 4, 6
  • Skin and soft tissue infections 3, 4, 6
  • Lower respiratory tract infections 3, 4, 6
  • Urinary tract infections 6
  • Gynecological infections 6
  • Febrile neutropenia 6