title: Dissemination and serotype modification potential of pSFxv_2, an O-antigen PEtN modification plasmid in Shigella flexneri.
abstract: The O-antigens of all Shigella flexneri serotypes, except serotype 6, share a linear tetrasaccharide repeat composed of one N-acetylglucosamine and three l-rhamnose residues, and differences between the serotypes are due to modification of various monosaccharide residues with glucosyl and/or O-acetyl and/or phosphoethanolamine (PEtN) groups. Plasmid-borne opt (formerly lpt-O) gene encoding a PEtN transferase which modifies the O-antigens of S. flexneri serotype X, 4a and Y strains and converts the hosts into MASF IV-1 (E1037) positive "variant" (v) Xv, 4av and Yv serotypes, respectively. In this study, we showed that the opt-carrying plasmid pSFxv_2 can transform strains of all S. flexneri serotypes (1-6) to confer them with the MASF IV-1 epitope recognized by monoclonal antibody MASF IV-1 and typing antiserum IV. The transformants possessed modified O-antigens with a PEtN group(s) at position 3 of one or two rhamnose residues. In some serotypes, the PEtN modification competed or/and interfered with glucosylation and O-acetylation at the same or its neighboring sugar residue. We also showed that the plasmid pSFxv_2 is mobilizable to other S. flexneri strains by conjugation. Although pSFxv_2-harboring S. flexneri strains found in clinical infections are restricted to serotypes Xv, 4av, Yv and, possibly, 6v, our results demonstrate a high potential of dissemination of this plasmid in S. flexneri and emergence of new S. flexneri serotypes.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, China CDC, P.O Box 5, Changping, Beijing, China.
authors.forename: Qiangzheng
authors.initials: Q
authors.lastname: Sun
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
authors.forename: Ruiting
authors.initials: R
authors.lastname: Lan
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.forename: Sof'ya N
authors.initials: SN
authors.lastname: Senchenkova
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Yiting
authors.initials: Y
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Luo
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
mesh_terms: D002240:Carbohydrate Sequence; D004983:Ethanolamines / Q000378:metabolism; D006031:Glycosylation; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D019081:O Antigens / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics*; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012703:Serotyping; D012763:Shigella flexneri / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D004983:Ethanolamines; D019081:O Antigens; D011994:Recombinant Proteins; C005448:phosphorylethanolamine; D016695:Glycosyltransferases
keywords: O-antigen; Shigella flexneri; pSFxv_2 plasmid; phosphoethanolamine modification; serotype conversion