Bacteriological and serological aspects of group A streptococcal pharyngotonsillitis caused by group A streptococci.

Several bacteriological and serological variables were studied in connection with a clinical treatment trial in 212 patients with group A streptococcal pharyngotonsillitis. Anaerobic incubation was not superior to incubation in 5% CO2 in air for the detection of group A streptococci. Saliva cultures were inferior to conventional throat cultures in detecting group A streptococci. No strains from patients with recurrences were found to be tolerant to penicillin. In several patients (all asymptomatic), group C and G streptococci were found in follow-up cultures. Group A streptococci serology was more often positive after two months than after one month, also in patients without recurrence.