What are the most common bacteria causing peritonsillar abscess?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 23, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Research

The most common bacteria causing peritonsillar abscess are Streptococcus pyogenes, Fusobacterium species, and other anaerobes, with polymicrobial infections being prevalent, as indicated by the most recent study 1.

Bacterial Causes of Peritonsillar Abscess

The bacterial causes of peritonsillar abscess are diverse, including both aerobic and anaerobic bacteria.

  • Streptococcus pyogenes is a common cause, isolated in 29% of cases in one study 1.
  • Fusobacterium species, including Fusobacterium necrophorum, are also frequently isolated, with a prevalence of 47% in the same study 1.
  • Other anaerobes like Actinomyces species and Peptostreptococcus are also commonly found.
  • The polymicrobial nature of these infections, with a mix of aerobic and anaerobic bacteria, is a key factor in their treatment, as it often requires broad-spectrum antibiotics.

Treatment Implications

The treatment of peritonsillar abscess typically involves drainage of the abscess, either through needle aspiration or incision and drainage, alongside antibiotic therapy.

  • Empiric antibiotic therapy may include amoxicillin-clavulanate or clindamycin, given the polymicrobial nature of the infection and the need to cover both aerobic and anaerobic bacteria 1, 2.
  • The choice of antibiotic should be guided by the results of microbiological cultures, when available, to ensure appropriate coverage of the causative organisms.

Clinical Considerations

In clinical practice, the management of peritonsillar abscess requires consideration of the potential for complications, such as abscess rupture or spread of infection, and the need for prompt and effective treatment to prevent these outcomes.

  • The use of broad-spectrum antibiotics, as suggested by the most recent evidence 1, reflects the polymicrobial nature of these infections and the importance of covering a wide range of potential pathogens.
  • The role of microbiological examination in guiding antibiotic therapy is also highlighted, particularly in cases where the infection does not respond to initial empiric treatment 1.

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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.