Antibiotic susceptibility in relation to serotype of Streptococcus pyogenes isolated from patients with acute infections at a pediatric outpatient clinic in Sendai (author's transl)

Abstract

Two series of clinical isolates of Streptococcusp yogenes subcultured from the throat swabs of the patients with acute infectious diseases at the pediatric outpatient clinic, Sendai National Hospital, Sendai City, were subjected to this study.The first series of the study was performed with the antibiotic susceptibility of 52 strains isolated from February to August, 1976, to ABPC, AMPC, ACPC, SBPC, Piperacillin (T-1220), CER, CEZ, CET, CEX, CLDM, JM, JM-P, EM, CP, TC, and MNC, determined as the minimal inhibitory concentration (MIC) by an agar dilution method. All the strains were found sensitive to both penicillins and cephalosporins, the antibacterial activity being in this order ABPC=AMPC> T-1220> ACPC> SBPC, CER>CEZ> CET> CEX, respectively. ighly cross resistant strains (MIC≥100μg/ml) to macrolides including CLDM were demonstrated.Measurements of antibiotic susceptibility to PC G, ABPC, CER, EM, CP, and TC as well as serotyping were made on 110 strains of Streptococcus pyogenes, as the second series of the study, isolated from April 1976 to March 1977. The distribution frequency of each serotype by utilizing T-typing revealed: T-12, 45 strains (40.9%); T-1, 30 strains (27.3%); T-4, 10 strains (9.1%); T-28, 9 strains (8.2%); T-22, 6 strains (5.5%); B 3264, 3 strains (2.7%); Imp. 19, l strin (0.9%); T-25, l strain (0.9%); nontypable, 5 strains (4.5%). The characterisitics of the distribution of resistant patterns in relation to serotypes were:(a) that all of the EM·ECP·ETC resistant strains were T-12, (b) that TC-single resistance distributed in T-1, T-4, T-12, T-28, and T-22, and (c) that all the strains of B 3264, Imp. 19, and T-25 were sensitive to all the antibiotics examined.The relationship of serotype and resistant pattern, the difference in the distribution of serotype and resistant pattern between isolates from Sendai area and those from other parts of Japan, and a possibility in the future of penicillin-resistant Streptococcus pyogenes comparing to Streptococcus pneumoniae have been briefly discussed.