Three hundred twelve university students (aged 15-30) presenting to a student health clinic with acute sore throat and 180 asymptomatic students were sampled by throat swab and the specimens were analyzed using PCR for F. necrophorum, Mycoplasma pneumonia, group A streptococci (GAS), and group C/G streptococci (GCS/GGS). F. necrophorum was detected in 20.5% of patients and 9.4% of controls. GAS was found in 10.3% of patients and 1.1% of asymptomatic students. Group C/G streptococci were detected in 9% of patients and 3.9% of controls. Mycoplasma pneumonia was found in 1.9% of patients and 0 controls. Clinical features of F. necrophorum-positive and GAS/GCS/GGS-positive cases were similar as assessed using the Centor score (fever, lack of cough, swollen, tender anterior cervical lymphadenopathy, and tonsillar exudates).
This is an interesting study that uses modern molecular techniques to understand the etiology of pharyngitis in young adults. While both Fusobacterium and Beta hemolytic streptococci are commonly associated with asymptomatic carriage in young adults, it is clear that both of these organisms are significant pathogens. (Lemierre’s syndrome is associated with F. necrophorum and various suppurative complications are associated with streptococci, although paradoxically Lemierre’s syndrome rarely follows clinical tonsillitis.)
Some important take-home points that can be gleaned from this paper include that penicillin is probably the antibiotic of choice in treating adolescent and young adult patients with high Centor scores, especially tonsillitis. All Fusobacteria are resistant to macrolides, and macrolide resistance is now common in GAS. Fortunately, these organisms remain susceptible to penicillin. It should be remembered that the results presented in this paper should not be extrapolated to pre-adolescent patients in whom both Fusobacterium and GCS/GGS are distinctly uncommon. While it is true that F. necrophorum may not uncommonly be associated with asymptomatic pharyngeal colonization, its pathogenicity is significant and testing (and treating) for this organism in patients in whom the pre-test probability of its pathogenicity is high, should be considered. Testing for F. necrophorummay become more practical and cost-effective as low cost multiplex assays are developed.