title: [Change in the biological properties of salmonellae in acquiring resistance to chloramphenicol].
abstract: Mutants of Salmonella typhimurium and Salmonella abony resistant to 40 microgram/ml of chloramphenicol were obtained during selection according to the method of Szybalski on Hottinger broth with increasing concentrations of the antibiotic. By the colony morphology the mutants were divided into 4 groups. The study of the mutant biological properties revealed changes in the growth rate characterized by elongation of the lag-phase and exponential phase, changes in the biochemical activity evident from lower fermentation rate of some carbohydrates and production of hydrogen sulphide and changes in some amino acid dependence. Increased cross resistance to tetracycline and benzylpenicillin and decreased resistance to kanamycin were noted. The LD50 of most mutants was increased as compared to that of the initial strains. Combination of several types of the changes was observed in some mutants. It is supposed that resistance to chloramphenicol in the mutants is due to mutations in several genes. Some of such genes had pleuotropic effect because of the changes in the structure of the ribosome 50S subunits.
mesh_terms: D001695:Biology; D002701:Chloramphenicol / Q000037:antagonists & inhibitors*; D004352:Drug Resistance, Microbial; D009154:Mutation / Q000187:drug effects; D012475:Salmonella / Q000187:drug effects*; D012486:Salmonella typhimurium / Q000187:drug effects; D014774:Virulence / Q000187:drug effects
chemical_list: D002701:Chloramphenicol
vernacular_title: Izmenenie biologicheskikh svoĭstv sal'monell v usloviiakh priobreteniia ustoĭchivosti k khloramfenikolu.