title: Attenuated mutants of Staphylococcus aureus with two temperature-sensitive lesions: isolation and characterization.
abstract: The feasibility of constructing attenuated mutants of Staphylococcus aureus with two temperature-sensitive (ts) lesions for ultimate development of a live-attenuated strain was investigated. Temperature-sensitive S. aureus strain G/1/2, which grows well at 31 degrees C but does not replicate at 37 degrees C, was subjected to chemical mutagenesis. After two enrichment cycles, fifteen mutants able to grow at 25 degrees C but unable to grow at 31 degrees C, were identified. Growth curves with temperature shifts from 25 to 31 degrees C, and from 31 to 37 degrees C confirmed that these were mutants with two lesions (dts), each with a different cut-off temperature. The reversion frequency of mutant G/1/2 at 37 degrees C was 2 x 10(-6) whereas those of several dts mutants were much lower (dts7: 7 x 10(-9) and dts12: 1 x 10(-9)). There was no increase in ts mutation reversion rate in response to prolonged incubation at 37 degrees C. The data support the further development of these mutants for use as a stable attenuated vaccine.
authors.affiliation: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
authors.forename: D O
authors.initials: DO
authors.lastname: Sordelli
authors.forename: M C
authors.initials: MC
authors.lastname: Cerquetti
authors.forename: F R
authors.initials: FR
authors.lastname: Buzzola
authors.forename: V E
authors.initials: VE
authors.lastname: García
authors.forename: M I
authors.initials: MI
authors.lastname: Gómez
authors.forename: A
authors.initials: A
authors.lastname: Morris Hooke
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000235:genetics* / Q000276:immunology; D002417:Cattle; D006358:Hot Temperature; D009603:Nitroso Compounds / Q000494:pharmacology; D010641:Phenotype; D017354:Point Mutation / Q000276:immunology*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000276:immunology / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D009603:Nitroso Compounds; D014613:Vaccines, Attenuated