scholarly journals Structure and genetics of Escherichia coli O antigens

2019 ◽  
Vol 44 (6) ◽  
pp. 655-683 ◽  
Author(s):  
Bin Liu ◽  
Axel Furevi ◽  
Andrei V Perepelov ◽  
Xi Guo ◽  
Hengchun Cao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Basis ◽  
Structural Diversity ◽  
Gene Clusters ◽  
Current Standard ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Or Groups ◽  
O Antigens

ABSTRACT Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and three (O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.

scholarly journals Structure of the O-antigen of Salmonella O66 and the genetic basis for similarity and differences between the closely related O-antigens of Escherichia coli O166 and Salmonella O66

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1642-1649 ◽  
Author(s):  
Bin Liu ◽  
Andrei V. Perepelov ◽  
Dan Li ◽  
Sof'ya N. Senchenkova ◽  
Yanfang Han ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Coding Region ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
New Genes ◽  
O Antigens ◽  
Antigen Structure

O-antigen is a component of the outer membrane of Gram-negative bacteria and is one of the most variable cell surface constituents, leading to major antigenic variability. The O-antigen forms the basis for bacterial serotyping. In this study, the O-antigen structure of Salmonella O66 was established, which differs from the known O-antigen structure of Escherichia coli O166 only in one linkage (most likely the linkage between the O-units) and O-acetylation. The O-antigen gene clusters of Salmonella O66 and E. coli O166 were found to have similar organizations, the only exception being that in Salmonella O66, the wzy gene is replaced by a non-coding region. The function of the wzy gene in E. coli O166 was confirmed by the construction and analysis of deletion and trans-complementation mutants. It is proposed that a functional wzy gene located outside the O-antigen gene cluster is involved in Salmonella O66 O-antigen biosynthesis, as has been reported previously in Salmonella serogroups A, B and D1. The sequence identity for the corresponding genes between the O-antigen gene clusters of Salmonella O66 and E. coli O166 ranges from 64 to 70 %, indicating that they may originate from a common ancestor. It is likely that after the species divergence, Salmonella O66 got its specific O-antigen form by inactivation of the wzy gene located in the O-antigen gene cluster and acquisition of two new genes (a wzy gene and a prophage gene for O-acetyl modification) both residing outside the O-antigen gene cluster.

scholarly journals Sequence Analysis of Four Shigella boydii O-Antigen Loci: Implication for Escherichia coli andShigella Relationships

2001 ◽  
Vol 69 (11) ◽  
pp. 6923-6930 ◽  
Author(s):  
Lei Wang ◽  
Wenjia Qu ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Clusters ◽  
Shigella Dysenteriae ◽  
E Coli ◽  
Shigella Boydii ◽  
Antigen Gene ◽  
O Antigen ◽  
Atypical Features ◽  
Serotype 5 ◽  
O Antigens

ABSTRACT Shigella strains are in reality clones ofEscherichia coli and are believed to have emerged relatively recently (G. M. Pupo, R. Lan, and P. R. Reeves, Proc. Natl. Acad. Sci. USA 97:10567–10572, 2000). There are 33 O-antigen forms in these Shigella clones, of which 12 are identical to O antigens of other E. coli strains. We sequenced O-antigen gene clusters from Shigella boydiiserotypes 4, 5, 6, and 9 and also studied the O53- and O79-antigen gene clusters of E. coli, encoding O antigens identical to those of S. boydii serotype 4 and S. boydii serotype 5, respectively. In both cases the S. boydii and E. coli O-antigen gene clusters have the same genes and organization. The clusters of both S. boydii 6 and S. boydii 9 O antigens have atypical features, with a functional insertion sequence and a wzx gene located in the orientation opposite to that of all other genes in S. boydii serotype 9 and an rmlC gene located away from other rml genes in S. boydii serotype 6. Sequences of O-antigen gene clusters from another threeShigella clones have been published, and two of them also have abnormal structures, with either the entire cluster or one gene being located on a plasmid in Shigella sonnei orShigella dysenteriae, respectively. It appears that a high proportion of clusters coding for O antigens specific toShigella clones have atypical features, perhaps indicating recent formation of these gene clusters.

scholarly journals Escherichia coli O123 O antigen genes and polysaccharide structure are conserved in some Salmonella enterica serogroups

2009 ◽  
Vol 58 (7) ◽  
pp. 884-894 ◽  
Author(s):  
Clifford G. Clark ◽  
Andrew M. Kropinski ◽  
Haralambos Parolis ◽  
Christopher C. R. Grant ◽  
Keri M. Trout-Yakel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Salmonella Enterica ◽  
Gene Clusters ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Antigenic Polysaccharide ◽  
O Antigens

The serotyping of O and H antigens is an important first step in the characterization of Salmonella enterica. However, serotyping has become increasingly technically demanding and expensive to perform. We have therefore sequenced additional S. enterica O antigen gene clusters to provide information for the development of DNA-based serotyping methods. Three S. enterica isolates had O antigen gene clusters with homology to the Escherichia coli O123 O antigen region. O antigen clusters from two serogroup O58 S. enterica strains had approximately 85 % identity with the E. coli O123 O antigen region over their entire length, suggesting that these Salmonella and E. coli O antigen regions evolved from a common ancestor. The O antigen cluster of a Salmonella serogroup O41 isolate had a lower level of identity with E. coli O123 over only part of its O antigen DNA cluster sequence, suggesting a different and more complex evolution of this gene cluster than those in the O58 strains. A large part of the Salmonella O41 O antigen DNA cluster had very close identity with the O antigen cluster of an O62 strain. This region of DNA homology included the wzx and wzy genes. Therefore, molecular serotyping tests using only the O41 or O62 wzx and wzy genes would not differentiate between the two serogroups. The E. coli O123 O-antigenic polysaccharide and its repeating unit were characterized, and the chemical structure for E. coli O123 was entirely consistent with the O antigen gene cluster sequences of E. coli O123 and the Salmonella O58 isolates. An understanding of both the genetic and structural composition of Salmonella and E. coli O antigens is necessary for the development of novel molecular methods for serotyping these organisms.

scholarly journals Relationships of the Escherichia coli O157, O111, and O55 O-Antigen Gene Clusters with Those of Salmonella enterica and Citrobacter freundii, Which Express Identical O Antigens

2004 ◽  
Vol 186 (19) ◽  
pp. 6536-6543 ◽  
Author(s):  
Gabrielle Samuel ◽  
John-Paul Hogbin ◽  
Lei Wang ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Common Ancestor ◽  
Gene Clusters ◽  
Citrobacter Freundii ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
The Common ◽  
O Antigens

ABSTRACT Escherichia coli O157, Salmonella enterica O30, and Citrobacter freundii F90 have identical O-antigen structures, as do E. coli O55 and S. enterica O50. The O-antigen gene cluster sequences for E. coli O157 and E. coli O55 have been published, and the genes necessary for O-antigen biosynthesis have been identified, although transferase genes for glycosidic linkages are only generic and have not been allocated to specific linkages. We determined sequences for S. enterica O30 and C. freundii F90 O-antigen gene clusters and compared them to the sequence of the previously described E. coli O157 cluster. We also determined the sequence of the S. enterica O50 O-antigen gene cluster and compared it to the sequence of the previously described E. coli O55 cluster. For both the S. enterica O30-C. freundii F90-E. coli O157 group and the S. enterica O50-E. coli O55 group of O antigens, the gene clusters have identical or nearly identical organizations. The two sets of gene clusters had comparable overall levels of similarity in their genes, which were lower than the levels determined for housekeeping genes for these species, which were 55 to 65% for the genes encoding glycosyltransferases and O-antigen processing proteins and 75 to 93% for the nucleotide-sugar pathway genes. Nonetheless, the similarity of the levels of divergence in the five gene clusters required us to consider the possibility that the parent gene cluster for each structure was in the common ancestor of the species and that divergence is faster than expected for the common ancestor hypothesis. We propose that the identical O-antigen gene clusters originated from a common ancestor, and we discuss some possible explanations for the increased rate of divergence that is seen in these genes.

scholarly journals The O-Antigen Gene Cluster of Escherichia coli O55:H7 and Identification of a New UDP-GlcNAc C4 Epimerase Gene

2002 ◽  
Vol 184 (10) ◽  
pp. 2620-2625 ◽  
Author(s):  
Lei Wang ◽  
Sandy Huskic ◽  
Adam Cisterne ◽  
Deborah Rothemund ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Gene Cluster ◽  
Gene Clusters ◽  
The Other ◽  
Recombination Site ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Usual Location

ABSTRACT Escherichia coli O55 is an important antigen which is often associated with enteropathogenic E. coli clones. We sequenced the genes responsible for its synthesis and identified genes for O-antigen polymerase, O-antigen flippase, four enzymes involved in GDP-colitose synthesis, and three glycosyltransferases, all by comparison with known genes. Upstream of the normal O-antigen region there is a gne gene, which encodes a UDP-GlcNAc epimerase for converting UDP-GlcNAc to UDP-GalNAc and is essential for O55 antigen synthesis. The O55 gne product has only 20 and 26% identity to the gne genes of Pseudomonas aeruginosa and E. coli O113, respectively. We also found evidence for the O55 gene cluster's having evolved from another gene cluster by gain and loss of genes. Only three of the GDP-colitose pathway genes are in the usual location, the other two being separated, although nearby. It is thought that the E. coli O157:H7 clone evolved from the O55:H7 clone in part by transfer of the O157 gene cluster into an O55 lineage. Comparison of genes flanking the O-antigen gene clusters of the O55:H7 and O157:H7 clones revealed one recombination site within the galF gene and located the other between the hisG and amn genes. Genes outside the recombination sites are 99.6 to 100% identical in the two clones, while most genes thought to have transferred with the O157 gene cluster are 95 to 98% identical.

scholarly journals A New O-Antigen Gene Cluster Has a Key Role in the Virulence of the Escherichia coli Meningitis Clone O45:K1:H7

2007 ◽  
Vol 189 (23) ◽  
pp. 8528-8536 ◽  
Author(s):  
Céline Plainvert ◽  
Philippe Bidet ◽  
Chantal Peigne ◽  
Valérie Barbe ◽  
Claudine Médigue ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Functional Organization ◽  
Gene Clusters ◽  
Neonatal Rat ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Pcr Method

ABSTRACT A new highly pathogenic clone of Escherichia coli meningitis strains harboring the unusual serogroup O45 has recently emerged in France. To gain insight into the pathogenicity of this new clone, we investigated the possible role of antigen O45 in the virulence of strain S88 (O45:K1:H7), representative of this emerging clone. We first showed that the S88 O-antigen gene cluster sequence differs from that of O45 in the reference strain E. coli 96-3285, suggesting that the two O45 polysaccharides, while probably sharing a community of epitopes, represent two different antigens. The unique functional organization of the two O-antigen gene clusters and the low DNA sequence homology of the orthologous genes suggest that the two loci originated from a common ancestor and have since undergone multiple recombination events. Phylogenetic analysis based on the flanking gene gnd sequences indicates that the S88 antigen O45 (O45S88) gene cluster may have been acquired, at least in part, from another member of the Enterobacteriaceae. Mutagenesis of the O45S88 antigen gene cluster was used for functional analysis of the loci and revealed the crucial role of the O polysaccharide in S88 virulence in a neonatal rat meningitis model. We also developed a PCR method to specifically identify the O45S88 antigen gene cluster. Together, our findings suggest that horizontal acquisition of a new O-antigen gene cluster, at least partly from another species, may have been a key event in the emergence and virulence of the E. coli O45:K1:H7 clone in France.

Deletion of the Escherichia coli O14:K7 O antigen gene cluster

2004 ◽  
Vol 50 (4) ◽  
pp. 299-302 ◽  
Author(s):  
Slade O Jensen ◽  
Peter R Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Common Antigen ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Enterobacterial Common Antigen ◽  
Colanic Acid ◽  
Rough Strain

Escherichia coli O14:K7 is a rough strain, lacking a typical O antigen, in which the enterobacterial common antigen is attached to the lipopolysaccharide core. The rough phenotype was previously mapped to the O antigen gene cluster; however, the nature of the nonfunctional locus was not defined. In this study, we have shown that the O antigen gene cluster of an O14:K7 type strain (Su4411/41) was most likely deleted via homologous recombination between the GDP–mannose pathway genes (manB and manC) of the colanic acid and O antigen gene clusters. A similar recombination event has previously been inferred for the deletion of E. coli Sonnei chromosomal O antigen genes. Therefore, recombination between the GDP–mannose pathway genes provides a convenient mechanism for the deletion of O antigen genes, which may occur if the typical O antigen becomes redundant.Key words: colanic acid, enterobacterial common antigen, GDP–mannose pathway, O14:K7, O antigen.

Escherichia coliserogroup O2 and O28ac O-antigen gene cluster sequences and detection of pathogenicE. coliO2 and O28ac by PCR

2010 ◽  
Vol 56 (4) ◽  
pp. 308-316 ◽  
Author(s):  
Pina M. Fratamico ◽  
Xianghe Yan ◽  
Yanhong Liu ◽  
Chitrita DebRoy ◽  
Brian Byrne ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Rapid Identification ◽  
Open Reading Frames ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Pcr Assays

The O-antigen gene clusters of Escherichia coli serogroups O2 and O28ac were sequenced, and PCR assays were developed to identify strains belonging to these 2 serogroups. Sixteen and 8 open reading frames were mapped to these loci in E. coli O2:H4 U 9-41 and E. coli O28ac:H25 96-3286, respectively. The wzx (O-antigen flippase) and wzy (O-antigen polymerase) genes in the E. coli O2 and O28ac O-antigen gene clusters were selected as targets for PCR assays for their identification. PCR assays targeting the wzx and wzy genes were specific for these serogroups, with one exception. Escherichia coli serogroup O42 strains gave positive results with wzx and wzy PCR assays targeting E. coli O28ac, and antiserum raised against O42 cross-reacted with serogroup O28ac strains. The O-antigen gene cluster of a strain of E. coli serogroup O42 was sequenced, and there were only 3 nt differences between the O-antigen gene clusters of the O28ac and O42 strains. Multiplex PCR assays targeting the O2 wzx gene, the stx1, stx2, hly, eae, and saa genes, and the O28ac wzx, ial, ipaC, and ipaH genes were developed for detecting Shiga toxin-producing E. coli O2 strains and enteroinvasive E. coli O28ac strains, respectively. The O2 and O28ac wzx and wzy genes can be used as diagnostic markers in PCR assays for rapid identification of these serogroups as an alternative to serotyping, and the multiplex PCR assays targeting serogroup-specific genes in combination with virulence genes can be used to identify and to detect pathogenic serogroup O2 and O28ac strains.

Detection of O antigens inEscherichia coli

2011 ◽  
Vol 12 (2) ◽  
pp. 169-185 ◽  
Author(s):  
Chitrita DebRoy ◽  
Elisabeth Roberts ◽  
Pina M. Fratamico
Keyword(s):  
Dna Sequences ◽  
Current Knowledge ◽  
Virulence Gene ◽  
Gene Clusters ◽  
Epidemiological Studies ◽  
Antigenic Specificity ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
O Antigens

AbstractLipopolysaccharide on the surface ofEscherichia coliconstitutes the O antigens which are important virulence factors that are targets of both the innate and adaptive immune systems and play a major role in host–pathogen interactions. O antigens are responsible for antigenic specificity of the strain and determine the O serogroup. The designation of O serogroups is important for classifyingE. colistrains, for epidemiological studies, in tracing the source of outbreaks of gastrointestinal or other illness, and for linking the source to the infection. For conventional serogroup identification, serotyping by agglutination reactions against antisera developed for each of the O serogroups has been used. In the last decade, many O-antigen gene clusters that encode for the enzymes responsible for the synthesis of the variable oligosaccharide region on the surface of the bacteria have been sequenced and characterized. Unique gene sequences within the O-antigen gene clusters have been targeted for identification and detection of many O groups using the polymerase chain reaction and microarrays. This review summarizes current knowledge on the DNA sequences of the O-antigen gene clusters, genetic-based methods for O-group determination and detection of pathogenicE. colibased on O-antigen and virulence gene detection, and provides perspectives on future developments in the field.

scholarly journals Development of PCR Assays Targeting Genes in O-Antigen Gene Clusters for Detection and Identification of Escherichia coli O45 and O55 Serogroups

2005 ◽  
Vol 71 (8) ◽  
pp. 4919-4924 ◽  
Author(s):  
Chitrita DebRoy ◽  
Pina M. Fratamico ◽  
Elisabeth Roberts ◽  
Michael A. Davis ◽  
Yanhong Liu
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Gene Cluster ◽  
Real Time Pcr ◽  
Gene Clusters ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Detection And Identification ◽  
Pcr Assays

ABSTRACT The Escherichia coli O45 O-antigen gene cluster of strain O45:H2 96-3285 was sequenced, and conventional (singleplex), multiplex, and real-time PCR assays were designed to amplify regions in the wzx (O-antigen flippase) and wzy (O-antigen polymerase) genes. In addition, PCR assays targeting the E. coli O55 wzx and wzy genes were designed based on previously published sequences. PCR assays targeting E. coli O45 showed 100% specificity for this serogroup, whereas by PCR assays specific for E. coli O55, 97/102 strains serotyped as E. coli O55 were positive for wzx and 98/102 for wzy. Multiplex PCR assays targeting the E. coli O45 and the E. coli O55 wzx and wzy genes were used to detect the organisms in fecal samples spiked at levels of 106 and 108 CFU/0.2 g feces. Thus, the PCR assays can be used to detect and identify E. coli serogroups O45 and O55.

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