What bacteria typically cause pharyngitis?

From the Guidelines

Group A Streptococcus is the most common bacterial cause of pharyngitis.

Bacterial Causes of Pharyngitis

• Group A Streptococcus is the predominant bacterial pathogen, and patients with symptoms suggesting a bacterial cause should be tested for it with a rapid antigen detection test, throat culture, or both 1.
• Other bacterial causes of pharyngitis include Arcanobacterium haemolyticum, Neisseria gonorrhoeae, Francisella tularensis, Yersinia enterocolitica, and Fusobacterium necrophorum 1.
• Fusobacterium necrophorum is implicated in approximately 10% to 20% of endemic pharyngitis cases in adolescents and is also a cause of Lemierre syndrome 1.

Clinical Features and Diagnosis

• Patients with a sore throat and associated symptoms, such as cough, nasal congestion, conjunctivitis, hoarseness, diarrhea, or oropharyngeal lesions, are more likely to have a viral illness and should not have further testing 1.
• The modified Centor criteria, which include fever by history, tonsillar exudates, tender anterior cervical adenopathy, and absence of cough, can be used to identify patients who have a low probability of group A streptococcal pharyngitis and do not warrant further testing 1.
• Laboratory confirmation is essential in making a precise diagnosis because physicians often greatly overestimate the probability that group A Streptococcus is the cause of pharyngitis 1.

From the Research

Bacterial Causes of Pharyngitis

• The most common bacterial cause of pharyngitis is Group A β-hemolytic streptococcus (GABHS), also known as strep throat 2, 3, 4, 5, 6
• GABHS is responsible for 5-15% of adult cases and 15-35% of child cases of pharyngitis in the United States 2
• Other bacterial causes of pharyngitis include:
  • C. pneumoniae 3
  • M. pneumoniae 3
  • Mycoplasmal and chlamydial pharyngitis 4
  • Gonococcal pharyngitis 4

Diagnosis and Treatment

• Diagnosis of GABHS pharyngitis can be made using clinical scoring systems, rapid antigen detection tests, throat culture, nucleic acid amplification tests, and machine learning and artificial intelligence 2
• Antibiotic treatment is effective in treating GABHS pharyngitis, with oral penicillin V and amoxicillin being the drugs of choice 5, 6
• Alternative antibiotics for patients with a non-anaphylactic allergy to penicillin include oral cephalosporin, clindamycin, clarithromycin, and azithromycin 6