A NEWLY PREVALENT TYPE OF BETA HEMOLYTIC STREPTOCOCCUS IN CHICAGO

Potter, E. V. (Dept. Medicine, Northwestern Univ., Chicago, III. 60611), A. C. Siegel and J. L Bearfleld. A newly prevalent type of beta hemolytic streptococcus in Chicago. Amer J Epidem 93: 102–110, 1971.—An outbreak of streptococcal infections with 7 cases suspected of having acute rheumatic fever occurred in an elementary school in Chicago during March, 1969. This outbreak led to the recognition of M 29-T 28 strains as prevalent in Chicago, comprising 58% of the typable strains in the south side school and 8% of the typable strains in a north side hospital. M 6-T 6 strains also were prevalent in Chicago, comprising 29% of the strains in the school and 8% in the hospital. Two cases of acute rheumatic fever in the hospital were associated with M 29-T 28 infections as well as 2 recurrences in children attending the hospital's Rheumatic Fever Clinic, and 2 additional cases had M 6-T 6 infections. The M 29-T 28 strains, therefore, have a rheumatogenic potential at least equal to that of the better known type 6 strains.