Group B beta-hemolytic streptococci causing pharyngitis.

Group B beta-hemolytic streptococci were isolated from the throats of 49 of 1,110 patients who had pharyngitis. Compared with patients whose throat cultures were negative for beta-hemolytic streptococci, those harboring group B were more likely to have enlarged tonsils (P less than 0.001), exudate (P less than 0.02), and tender enlarged anterior cervical lymph nodes (P less than 0.01). Group B should not necessarily be dismissed as a nonpathogen when identified in the pharynx of patients with exudative pharyngitis; laboratories which report beta-hemolytic streptococcal isolates from the pharynx only as group A or non-group A should be encouraged to perform definitive group identification of all beta-hemolytic isolates to further evaluate the role of other streptococcal groups as the causative agents for pharyngitis.