From the Guidelines
Zosyn (piperacillin/tazobactam) is effective against gram-negative anaerobic rods, including Bacteroides fragilis and other clinically significant anaerobic gram-negative bacilli, making it a suitable option for treating infections where anaerobic coverage is essential. The combination of piperacillin, an extended-spectrum penicillin, and tazobactam, a beta-lactamase inhibitor, provides broad-spectrum activity against gram-positive, gram-negative, and anaerobic organisms 1. The beta-lactamase inhibitor component (tazobactam) enhances piperacillin's effectiveness by protecting it from degradation by bacterial enzymes that would otherwise inactivate the antibiotic.
Some key points to consider when using Zosyn include:
- The typical adult dosing of Zosyn is 3.375g or 4.5g IV every 6-8 hours, with adjustments needed for renal impairment.
- Zosyn is particularly useful for mixed infections involving anaerobes, such as intra-abdominal infections, diabetic foot infections, aspiration pneumonia, and complicated skin and soft tissue infections where anaerobic coverage is essential.
- The use of Zosyn in patients with ESBLs infections is still controversial, even if in stable patients, it may be still a therapeutic chance 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 1.
Overall, Zosyn is a valuable option for treating infections involving gram-negative anaerobic rods, but its use should be guided by local resistance patterns and individual patient factors.
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
Antibiotic Coverage
- Zosyn (piperacillin/tazobactam) has a broad spectrum of antibacterial activity, including coverage of Gram-negative aerobic bacteria and anaerobic bacteria 3.
- The combination of piperacillin and tazobactam is effective against many pathogens producing beta-lactamases, making it a useful option for treating polymicrobial infections caused by aerobic or anaerobic beta-lactamase-producing bacteria 3.
- Specifically, piperacillin/tazobactam has been shown to be effective against Bacteroides fragilis, a common Gram-negative anaerobic rod, in several studies 4, 5.
Efficacy Against Bacteroides fragilis
- A retrospective study comparing the effectiveness of carbapenems and tazobactam/piperacillin as an empirical treatment for patients infected with B. fragilis found that tazobactam/piperacillin treatment significantly improved inflammatory markers and had a lower percentage of patients switching to broad-spectrum antibiotics 4.
- Another study found that piperacillin/tazobactam was active against almost all isolates of B. fragilis, although some non-fragilis B. fragilis group species were resistant to piperacillin alone 5.
- The combination of piperacillin and tazobactam has been shown to be effective against B. fragilis in clinical trials, with high clinical and bacteriological response rates 3, 4.
Comparison to Other Antibiotics
- Piperacillin/tazobactam has been compared to other antibiotics, such as carbapenems and cefoxitin, and has been found to be effective and well-tolerated 3, 5.
- The choice of antibiotic for treating B. fragilis infections should be based on the specific circumstances of the patient and the suspected or confirmed pathogen 4, 5.