Studies on the Hemolytic Streptococci Isolated in Recent Years

Abstract

Twelve group antisera and 36 type antisera were prepared by the author using standard strains of hemolytic streptococcus originating from Lancefield and Updyke (cordially presented by Institute for Infectious Diseases and Institute for Preventive Medicine). Hemolytic streptococci isolated from scarlet fever patients were classified by means of these sera using precipitation test in order to clarify the relationship between the classification and the clinical pictures.
1) For the preparation of group antisera, chrom vaccine was mainly used, aiming at no high precipitaion titer, so that antisera necessitating no absorption were obtained by 5 inoculations during 20 days. However, the crossing between D group (C3) and F group (H60R) could not be eliminated.
2) For the preparation of type antsera (A group), the antigens obtained by bacterial body destroying method (Conroy, Updyke) were injected to the animals 5 times during 20 days (modification by the author). As a result of comparative examination of various methods of precipitation test, the following was found the best: absorption by the strain of corresponding type according to the serum antibody titer, elimination of the cross reaction by dilution with 1.5% salt solution of gum arabicum, a definite concentration of antigens extracted by HC1. Observing these precautions, 36 type antisera were prepared.
3) The isolation rate of pharyngeal streptococci from scarlet fever patients was 24.2% in the cases treated with antibiotics and 95.6% given no antibiotics according to the study of 1, 373 cases by the author. The isolation rate according to the year did not demonstrate any great difference.
4) Both of the larynx and the nasal cavity demonstrated the isolation rate 14.7%. so that the role of nasal cavity in epidemics did not seem to be great.
5) Six scarlet fever patients were examined on the purity of the streptococci isolated. All of them demonstrated one pure strain belonging to the same group and type excet one case, which proved one colony out of a great number of colonies on a culture medium to be sufficient for the determination of type.
6) Many examinations on the type and group were carried out in the course of the disease in order to study the variation of type. Less than the half of 198 cases investigated demonstrated a variation of type, which was associated with an aggravation of clinical picture twice as frequently as in the cases witnout the variation of type.
On the other hand, aggravation was observed in a high rate in the cases treated with anibiotics at the beginning of the disease as compared with the cases given no antibiotics regardless of the variation of type. Therefore, an improvement must be considered regarding the way of patient's isolation and the duration and method of antibiotic therapy.
7) The strains isolated from scarlet fever patients of 9 families were investigated on the identity of strain, only one family demonstarting different types.
8) Thirty eight families were investigated on the type difference between the strains isolated from patients and those from healthy persons in the same family, the isolation rate being almost the same among patients and healthy members. The families with the same type among the family members were 75%.
9) Scarlet fever patients complicated by nephritis demonstrated no particular type. The appearance of a certain type to predominate is likely to be caused by a high incidence of the type in scarlet fever patients.
10) Among the strains isolated, A group predominated overwhelmingly, followed by C and then by G group.
11) Out of 2, 139 A group strains isolated from 1954 to 1959, 9: 11 was most frequently encountered in 1954-1955 and 6 most frequently in 1956-1959, showing a variation of isolation rate according to the year. A variation according to the month was also confirmed. Furthermore, a variation according to the district was noticed.