title: Stepwise acquisition of multiple drug resistance by beta-hemolytic streptococci and difference in resistance pattern by type.
abstract: We collected 1,353 strains of beta-hemolytic streptococci of groups A, B, C, and G (1,176 strains of which were group A) isolated in 26 institutions throughout Japan in 1972-1974. The strains were grouped and T-typed by our specific group-and T-factor sera, and the minimal inhibitory concentrations of 10 antibiotics were assayed by the standard method. Resistant strains from the above collection were classified according to group, T-type, and drug resistance pattern. Our data on T-types for 1964-1971 and on drug resistance for 1966-1971 were used to interpret the detected long-term variations in T-type and drug resistance. The stepwise acquisition of multiple drug resistance, the difference in resistance pattern between predominant T-types, and the rarity of single-macrolide resistance were demonstrated.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D007564:Japan; D008826:Microbial Sensitivity Tests; D013290:Streptococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013291:Streptococcus / Q000187:drug effects*; D013292:Streptococcus agalactiae / Q000187:drug effects; D013297:Streptococcus pyogenes / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents