Which is more effective for anaerobic mouth coverage, Ertapenem or Piperacillin/Tazobactam?

From the Guidelines

Piperacillin/Tazobactam is more effective for anaerobic mouth coverage than Ertapenem.

Key Points

• Both Ertapenem and Piperacillin/Tazobactam are effective against anaerobic bacteria, but Piperacillin/Tazobactam has a broader spectrum of activity against gram-negative bacteria, including Pseudomonas aeruginosa 1.
• The Surgical Infection Society and the Infectious Diseases Society of America recommend Piperacillin/Tazobactam as a first-line treatment for intra-abdominal infections, including those caused by anaerobic bacteria 1.
• Ertapenem is a carbapenem antibiotic that is effective against a wide range of bacteria, including anaerobes, but its use is generally reserved for more severe infections or those caused by multidrug-resistant organisms 1.
• Piperacillin/Tazobactam is often preferred over Ertapenem for anaerobic coverage due to its broader spectrum of activity and lower risk of promoting antibiotic resistance 1.

Anaerobic Coverage

• Both Ertapenem and Piperacillin/Tazobactam provide adequate anaerobic coverage, but Piperacillin/Tazobactam is generally considered more effective against a broader range of anaerobic bacteria, including Bacteroides and Fusobacterium species 1.
• The dosage of Piperacillin/Tazobactam is typically 3.375-4.5 g IV every 6-8 hours, while Ertapenem is typically dosed at 1 g IV every 24 hours 1.

Clinical Use

• Piperacillin/Tazobactam is often used in combination with other antibiotics, such as metronidazole or a fluoroquinolone, to provide broad-spectrum coverage against both aerobic and anaerobic bacteria 1.
• Ertapenem is often reserved for use in patients with severe infections or those who are at high risk of developing antibiotic-resistant infections 1.

From the FDA Drug Label

At least 90% of the following bacteria exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for ertapenem ... Anaerobic bacteria: Bacteroides vulgatus Clostridium perfringens Fusobacterium spp Ertapenem was evaluated in adults for the treatment of complicated intra-abdominal infections in a randomized, double-blind, non-inferiority clinical trial. This trial compared ertapenem (1 g intravenously once a day) with piperacillin/tazobactam (3. 375 g intravenously every 6 hours) for 5 to 14 days The combined clinical and microbiologic success rates in the microbiologically evaluable population at 4 to 6 weeks posttherapy (test-of-cure) were 83.6% (163/195) for ertapenem and 80. 4% (152/189) for piperacillin/tazobactam.

Efficacy Comparison:

• Ertapenem and Piperacillin/Tazobactam have been compared in clinical trials for the treatment of complicated intra-abdominal infections.
• The clinical success rates for ertapenem and piperacillin/tazobactam were 83.6% and 80.4%, respectively.
• Anaerobic coverage: Both drugs have activity against anaerobic bacteria, but the clinical trial data does not provide a direct comparison of their efficacy for anaerobic mouth coverage.
• Key finding: The available data does not support a conclusion that one drug is more effective than the other for anaerobic mouth coverage 2.

From the Research

Comparison of Ertapenem and Piperacillin/Tazobactam for Anaerobic Mouth Coverage

• Ertapenem has been shown to be active against most species of anaerobic bacteria, including those isolated from intra-abdominal infections, with MIC(90)s ranging from 1 to 4 mg/L for most Bacteroides fragilis group isolates 3.
• In comparison, piperacillin/tazobactam is also effective against anaerobic bacteria, but ertapenem has been found to be equivalent to or better than piperacillin-tazobactam in activity against most anaerobic species isolated from infections 3, 4.
• A study comparing the efficacy of ertapenem and piperacillin-tazobactam for treatment of mixed anaerobic complicated intra-abdominal, complicated skin and skin structure, and acute pelvic infections found that cure rates for all evaluable patients with anaerobic infection were 89.3% for ertapenem and 85.9% for piperacillin-tazobactam, indicating that the two treatments were equivalent 5.
• Other studies have also listed ertapenem and piperacillin/tazobactam as effective antimicrobials against anaerobic organisms, along with other agents such as metronidazole, chloramphenicol, and tigecycline 6, 7.

Efficacy of Ertapenem and Piperacillin/Tazobactam Against Anaerobic Bacteria

• Ertapenem has been shown to have potent activity against the majority of anaerobic isolates from intra-abdominal infections, with MIC(90)s species specific for Clostridium, ranging from 0.06 mg/L for Clostridium perfringens to 4 mg/L for Clostridium clostridioforme 3.
• Piperacillin/tazobactam is also effective against anaerobic bacteria, including Bacteroides fragilis group and peptostreptococci, but ertapenem has been found to be more potent against some anaerobic species 4, 5.
• The choice of antimicrobial agent for treatment of anaerobic infections should be based on the severity of the infection, the suspected or confirmed pathogens, and the patient's underlying medical conditions 6, 7.