Studies on the Post-therapeutic Reinfection of Group A Hemolytic Streptococci in Scarlet Fever Patients

Abstract

1. The authors demonstrated that Group A hemolytic streptococci reappeared shortly after the antibiotic treatment had been discontinued, on the throat cultures of 126 (25%) among 494 confirmed cases of scarlet fever admitted to the Komagome Hospital during the past 3 years.
2. Baced on the data obtained from 55 inpatients, in whom the types of Group A hemolytic streptococci isolated before and after the antibiotic treatment were serologically determined, they were classified into 3 categories designated as (1) relapse group, including 32 cases who excreted same type of streptococci through the course of illness, (2) reinfection group, comprising 19 cases who occurred the type alteration of streptococci before and after the treatment, and (3) mixed group of (1) and (2), including 4 cases respectively.
3. The authors estimated, therefore, that approximately one tenth of the inpatients would be reinfected with Group A hemolytic streptococci from other patients during their hospitalization.
4. The most frequent types of Group A streptococci isolated from the relapsing and reinfected cases were shown to be “Untyped” or Type 6 as well as those obtained on admission.
5. There were almost no differences in the clinical findings between the relapse and reinfection roups.
6. Incubation period in the reinfection group were generally 2 to 3 days, but, being shorter in some cases.
7. The authors emphasize, as the result of this report, that in assessing the therapeutic effects of antibiotics on scarlet fever, it is indispensable to exclude the reinfection and occasional contamination with streptococci after treatment by continuous examination for streptococci from patients and type-determination of the isolates.