What is the Most Common Cause of Bacterial Sore Throat? (Hint... It is NOT Strep)

Viruses may cause the most sore throats, but when it comes to bacterial sources, strep seems to get a bad rap as THE germ that causes tonsillitis and pharyngitis. However, a 2015 study from University of Alabama suggests that group A strep which is detected by the commonly used rapid strep swab only accounts for about 10% of bacterial sore throats.

The real culprit that causes most of the bad non-viral sore throats at least in young adults (15-30 years) is Fusobacterium necrophorum. This germ accounts for about 20% of all sore throats and is treated slightly differently from strep. Typically, the antibiotic of choice is augmentin or clindamycin, especially given the risk of Lemierre's syndrome. But the most important take-home point is that if a patient appears to have an acute tonsillitis/pharyngitis, antibiotics should be prescribed even if strep test negative.

Other germs that were found to cause a sore throat were Group C/G strep in 9% and Mycoplasma pneumoniae in 1.9%.

These findings just goes to show that there may still be a bacterial throat infection even if strep testing comes back normal.

Unfortunately, there is no quick or easy test to detect these other organisms at this time. The researchers had to develop a new PCR test for the purposes of this study.

Regardless of the culprit germ, tonsillectomy and/or adenoidectomy can be considered if enough infections occur.

Watch a video showing how a tonsillectomy is performed here!

Reference:
The Clinical Presentation of Fusobacterium-Positive and Streptococcal-Positive Pharyngitis in a University Health Clinic: A Cross-sectional Study. Ann Intern Med. 2015;162(4):241-247. doi:10.7326/M14-1305