Does Augmentin (amoxicillin-clavulanate) cover anaerobic bacteria?

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From the Guidelines

Augmentin (amoxicillin-clavulanate) is effective against many anaerobic bacteria, making it a suitable choice for infections where anaerobes are likely contributors. This antibiotic combines amoxicillin with clavulanic acid, which inhibits beta-lactamase enzymes that would otherwise break down amoxicillin, providing good coverage against many gram-positive aerobes, some gram-negative aerobes, and importantly, many anaerobic bacteria including Bacteroides fragilis, Prevotella, Porphyromonas, Fusobacterium, and Peptostreptococcus species 1. According to the 2014 update by the Infectious Diseases Society of America, amoxicillin-clavulanate is recommended for infections following animal or human bites, which are often polymicrobial and include anaerobic organisms 1.

Key points to consider when using Augmentin for anaerobic coverage include:

  • The combination of amoxicillin and clavulanic acid provides broad-spectrum activity against aerobic and anaerobic bacteria
  • Augmentin is particularly useful for mixed aerobic-anaerobic infections such as aspiration pneumonia, intra-abdominal infections, diabetic foot infections, and certain skin and soft tissue infections
  • Common dosing for adults is 875/125 mg twice daily or 500/125 mg three times daily for 7-14 days, depending on the infection being treated
  • For severe anaerobic infections, other agents like metronidazole or carbapenems might be preferred, as they have more targeted activity against anaerobic bacteria 1.

It's also important to note that the bacteriology of wounds can vary, and empirical therapy might miss pathogens, highlighting the importance of considering the specific type of infection and the potential pathogens involved when selecting antimicrobial therapy 1.

From the Research

Anaerobic Coverage of Augmentin

  • Augmentin, a combination of amoxicillin and clavulanate, is a broad-spectrum antibacterial agent 2.
  • The combination of a penicillin and a beta-lactamase inhibitor, such as amoxicillin plus clavulanate, is effective against anaerobes 3, 4.
  • Augmentin is included in guidelines and recommendations for the treatment of bacterial infections, including those caused by anaerobes 2.
  • However, the primary use of Augmentin is in the treatment of community-acquired respiratory tract infections, and its effectiveness against anaerobes is not its primary indication 2.

Effective Antimicrobials Against Anaerobes

  • The most effective antimicrobials against anaerobes are metronidazole, carbapenems, combinations of a beta-lactam and a beta-lactamase inhibitor, chloramphenicol, tigecycline, and clindamycin 3, 4.
  • Metronidazole is still considered the criterion standard for therapy of anaerobic infections 5.
  • Augmentin, while effective against some anaerobes, is not the first-line treatment for anaerobic infections 3, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Spectrum and treatment of anaerobic infections.

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy, 2016

Research

Antimicrobials therapy of anaerobic infections.

Journal of chemotherapy (Florence, Italy), 2016

Research

Metronidazole is still the drug of choice for treatment of anaerobic infections.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2010

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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