Beta Hemolytic Streptococci and Rheumatic Fever in Miami, Florida: II. Antistreptolysin O Titer Determinations between October 1954 and May 1955

Abstract

1. Antistreptolysin O (ASLO) titers of blood drawn from 333 children attending the first three grades of public schools in Miami, Florida, were determined in conjunction with studies of beta hemolytic streptococci isolated from the throats of the same subjects. 2. Forty-eight of 472 blood samples yielded titers of 250 or above; 21 sera had titers of 333 or higher. 3. The overall average titer and indices were 102.5 (average titer), 3.96 (arithmetic index) and 8.08 (modified index). These levels were lowest in the bloods of those children from whose throats no streptococci or only group B organisms were isolated; next higher with groups F and G; still higher with group C; highest with group A organisms, non-typable and typable. 4. ASLO titers of successive blood samples taken from children from whose throats group A beta hemolytic streptococci were isolated, showed a rise of 2 tubes or more in 29.1 per cent of the 55 children with typable strains and 27.0 per cent of the 37 with non-typable strains. A similar rise was demonstrated in 16.7 per cent of the 18 children with group C streptococci, but only 5.1 per cent of the 99 children from whom no beta hemolytic streptococci were isolated. 5. Sera from 66 children who participated in both this investigation and in a study during the previous year, revealed higher average ASLO titers and indices in the second year (1954-1955) than in the first (1953-1954). 6. High colony counts on original isolation plates were more likely to be associated with a 2-tube or greater ASLO titer elevation, than were low colony counts. 7. The value of single and of serial ASLO titer determinations was considered for the estimation of host status. These serological data furnish limited information and require careful analysis in the evaluation of host-organism interrelationship and of the etiologic relationship of beta hemolytic streptococci to rheumatic fever in the Miami area.