title: [Interrelation of virulent and avirulent (vaccinal) strains of Shigella flexneri 2A in long-term bacterial carriage in gnotobiotic rats].
abstract: The ability of S. flexneri 2a virulent and avirulent (vaccine) strains No. 516 and No. 516 m to displace one another during long-term carrier state in germ-free rats has been studied. The long-term persistence of the vaccine strain in the intestine of the rats has been shown to produce colonization resistance to subsequent infection with the virulent culture of these bacteria. During carrier state in rats progressive S--R dissociation of the bacteria occurs, type II antigen is lost with simultaneous retention of group 3, 4 antigens and the resulting transformation of S. flexneri, serotype 2a, into variant y; the virulence of Shigella S-forms is also lost.
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000627:therapeutic use; D002353:Carrier State / Q000382:microbiology* / Q000517:prevention & control / Q000628:therapy; D002908:Chronic Disease; D004405:Dysentery, Bacillary / Q000382:microbiology* / Q000517:prevention & control / Q000628:therapy; D005856:Germ-Free Life; D006168:Guinea Pigs; D051381:Rats; D011916:Rats, Inbred F344; D012763:Shigella flexneri / Q000276:immunology / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001428:Bacterial Vaccines
vernacular_title: Vzaimootnosheniia virulentnogo i avirulentnogo (vaktsinnogo) shtammov Shigella flexneri 2A pri dlitel'nom bakterionositel'stve u krys-gnotobiontov.