From the Guidelines
Yes, Zosyn (piperacillin/tazobactam) effectively covers gram-negative anaerobic rods. Zosyn is a combination antibiotic consisting of piperacillin, an extended-spectrum penicillin, and tazobactam, a beta-lactamase inhibitor. This combination provides excellent coverage against many gram-negative anaerobes including Bacteroides fragilis, Prevotella species, Fusobacterium species, and other clinically significant anaerobic gram-negative bacilli, as stated in the 2017 WSES guidelines for management of intra-abdominal infections 1. The typical adult dosage of Zosyn is 3.375g or 4.5g IV every 6-8 hours, with adjustments needed for renal impairment. Some key points to consider when using Zosyn include:
- The tazobactam component protects piperacillin from degradation by beta-lactamase enzymes that many anaerobes produce, which would otherwise render the antibiotic ineffective.
- Zosyn is particularly valuable for treating mixed aerobic and anaerobic infections such as intra-abdominal infections, complicated skin and soft tissue infections, and aspiration pneumonia where gram-negative anaerobes are often involved in the infectious process.
- The use of Zosyn in patients with ESBLs infections is still controversial, even if in stable patients, it may be still a therapeutic chance, as mentioned in the guidelines 1.
- It is essential to consider the local resistance epidemiology and the individual risk for infection by resistant pathogens when choosing empiric antibiotic regimens, including Zosyn, for patients with intra-abdominal infections 1.
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 [see Indications and Usage (1)]: Anaerobic bacteria Bacteroides fragilis group (B. fragilis, B. ovatus, B. thetaiotaomicron, and B. vulgatus)
Zosyn (piperacillin/tazobactam) covers Gram-negative anaerobic rods, specifically Bacteroides fragilis group, which includes Gram-negative anaerobic rods. 2
From the Research
Antibacterial Coverage of Zosyn (Piperacillin/Tazobactam)
- Zosyn (piperacillin/tazobactam) has a broad spectrum of antibacterial activity, covering most Gram-positive and Gram-negative aerobic bacteria and anaerobic bacteria, including many pathogens producing beta-lactamases 3, 4, 5.
- The combination is effective against Gram-negative aerobic bacteria, such as Enterobacteriaceae and Pseudomonas aeruginosa, as well as against Gram-positive aerobic bacteria and anaerobic bacteria, including Bacteroides fragilis 3, 4.
- Specifically, piperacillin/tazobactam has been shown to be active against Gram-negative anaerobic rods, including Bacteroides species 3, 4.
Efficacy Against Anaerobic Bacteria
- Studies have demonstrated that piperacillin/tazobactam is effective against anaerobic bacteria, including Bacteroides fragilis, Bacteroides distasonis, and Bacteroides ovatus 4, 6.
- However, some strains of non-fragilis B. fragilis group species may be resistant to piperacillin/tazobactam 6.
- The combination of piperacillin/tazobactam has been shown to be effective in the treatment of intra-abdominal infections, which often involve anaerobic bacteria 3, 4, 5.
Clinical Use of Zosyn (Piperacillin/Tazobactam)
- Zosyn (piperacillin/tazobactam) is used to treat a variety of infections, including lower respiratory tract infections, intra-abdominal infections, urinary tract infections, gynaecological and skin/soft tissue infections, and febrile neutropenia 3, 4, 5.
- The combination is often used as an empirical first-line option in moderate to severe bacterial infections, due to its broad spectrum of activity and clinical efficacy 5.