RT Journal Article SR Electronic(1) A1 Okamura, Noboru A1 Nakaya, Rintaro A1 Suzuki, Kenji A1 Kondo, Seiichi A1 Hisatsune, Kazuhito A1 Imagawa, Yatsuka A1 Sagara, Hiroko A1 Matsubara, YoshioYR 1988 T1 Differences among Shigella spp. in Susceptibility to the Bactericidal Activity of Human Serum JF Microbiology, VO 134 IS 7 SP 2057 OP 2065 DO https://doi.org/10.1099/00221287-134-7-2057 PB Microbiology Society, SN 1465-2080, AB Clinical isolates of Shigella spp. were examined for their susceptibility to human serum. The susceptibility of the strains to immune and nonimmune human serum was dependent upon the size of the bacterial inoculum and the concentration of serum. There were differences among Shigella spp. in susceptibility to human serum: S. sonnei strains were the least susceptible, strains of S. boydii and S. flexneri serotype 6 were intermediate, and those of S. flexneri other than serotype 6 and S. dysenteriae were the most susceptible. Experiments in which heat-treated (56 °C for 30 min, or 50 °C for 20 min) serum was used, and analysis of activation of complement by lipopolysaccharides (LPS) from each Shigella sp., suggested that LPS composition, especially the O antigen polysaccharide chains, contributes to the differences among Shigella spp. in susceptibility to human serum., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-134-7-2057