Bacterial interference in the throat flora during a streptococcal tonsillitis outbreak in an apartment house area.

During an outbreak of streptococcal tonsillitis in an apartment house area the interfering capacity of alpha-hemolytic streptococci isolated from the inhabitants' throat flora on the beta-hemolytic streptococcal strains recovered during the outbreak was investigated. Strains of alpha-streptococci with an inhibiting capacity on beta-streptococci were isolated mainly from individuals seemingly resistant to streptococcal tonsillitis while patients with repeated tonsillitis often had beta-streptococcal strains inhibiting the growth of the patients own alpha-streptococcal flora. Inhibiting alpha-streptococcal strains were isolated in high frequency in healthy patients that had recently recovered from tonsillitis.