Roberts, FleurJennison, AmyVerma, Naresh2015-12-130928-8244http://hdl.handle.net/1885/83453Shigella flexneri is endemic in most developing countries and responsible for the highest mortality rate among the Shigella species. The attenuated serotype Y S. flexneri strain SFL124 has been used as the parental strain for the development of recombinant vaccines expressing multiple O-antigen structures. During the development of one such multivalent vaccine, a region of gtrII homology was found in SFL124. Sequencing and analysis of this region revealed the presence of an insertion element interrupted serotype 2a serotype-conversion locus in the serotype Y vaccine strain SFL124. The data presented suggests that SFL124 has derived from a serotype 2a background.Keywords: bacterial vaccine; glucosyltransferase; O antigen; recombinant vaccine; shigella flexneri vaccine; Shigella vaccine; unclassified drug; antigen expression; article; bacterial strain; controlled study; gene insertion; gene locus; microbial attenuation; non Glucosyl transferases; Serotype reversion; Shigella flexneri200510.1016/j.femsim.2005.05.0022015-12-12