Bacteroides melaninogenicus. Its recovery from tonsils of children with acute tonsillitis.

The presence of encapsulated and abscess-forming organisms belonging to the Bacteroides melaninogenicus group was investigated in 25 children with acute tonsillitis, and in 23 children without tonsillar inflammation (control). Encapsulated organisms of the B melaninogenicus group were found in 23 of 25 children with acute tonsillitis as compared with five of 23 controls. Subcutaneous inoculation into mice of the Bacteroides strains isolated from patients with tonsillitis produced abscesses in 17 of 25 instances, as compared with nine of the 23 of the controls. Group A streptococci were recovered from the tonsils of five children with tonsillitis and from four of the control group. These findings suggest a possible pathogenic role for the B melaninogenicus group in acute tonsillar infection in children.