Effect of different purine auxotrophic mutations on mouse-virulence of a Vi-positive strain of Salmonella dublin and of two strains of Salmonella typhimurium.

摘要: Ten cfu of a Vi-positive strain Salmonella dublin, given i.p. to BALB/c mice, caused death. Of transductional derivatives with nutritional requirements expected reduce virulence, those complete blocks at aroA (therefore aromatic-dependent) or purA adenine-dependent) were non-virulent; no deaths from inocula 10(6) 10(7) cfu, respectively. Transductants identified purF, purG, purC in the purJHD operon, all purine requirement satisfied by hypoxanthine any other purine, reduced some 10(4) or, for most derivatives, only 10(2) cfu. Blocks guaA guaB, causing guanine requirement, likewise resulted 10(2). Transductional two mouse-virulent (LD50, i.p., less than 25 cfu) strains S. typhimurium similarly tested, generally similar results, that and purB (adenine-requiring) transductants non-virulent, 2.5 x purG defects (hypoxanthine-responding) retained partial virulence. However, guaB (guanine-requiring) much virulence; mice survived 10(5) but one In both dublin tests autopsy cultures showed fatal infections multiplication auxotrophic strain, not non-exacting revertants.