Association of group C beta-hemolytic streptococci with endemic pharyngitis among college students.

Abstract

Throat cultures were performed throughout 2 school years to determine whether non-group A beta-hemolytic streptococci (NGA BHS) could be isolated more frequently in 232 college students who had symptomatic pharyngitis than from 198 age-matched controls with noninfectious problems. Duplicate throat swabs were inoculated onto plates that contained sheep blood agar, one plate being incubated in a 5% CO2 atmosphere and the other in an anaerobic environment. The BHS were grouped using latex agglutination. Among the NGA BHS, only those from group C were isolated significantly more often among the patients compared with the controls (26% vs 11%). Quantitative colony counts of isolates of group C BHS were generally higher among patients than controls. Patients with group C BHS had fever, exudative tonsillitis, and anterior cervical adenopathy significantly more frequently than did patients who had throat cultures that were negative for group C BHS. Group C BHS were epidemiologically associated with endemic pharyngitis in this college student population.