scholarly journals Sequence-based typing of genetic targets encoded outside of the O-antigen gene cluster is indicative of Shiga toxin-producing Escherichia coli serogroup lineages

2007 ◽  
Vol 56 (5) ◽  
pp. 620-628 ◽  
Author(s):  
Matthew W. Gilmour ◽  
Adam B. Olson ◽  
Ashleigh K. Andrysiak ◽  
Lai-King Ng ◽  
Linda Chui
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Dna Sequences ◽  
Shiga Toxin ◽  
Clinical Isolates ◽  
Comparative Analyses ◽  
Antigen Gene ◽  
O Antigen ◽  
Additional Support ◽  
H Serotypes

Serogroup classifications based upon the O-somatic antigen of Shiga toxin-producing Escherichia coli (STEC) provide significant epidemiological information on clinical isolates. Each O-antigen determinant is encoded by a unique cluster of genes present between the gnd and galF chromosomal genes. Alternatively, serogroup-specific polymorphisms might be encoded in loci that are encoded outside of the O-antigen gene cluster. Segments of the core bacterial loci mdh, gnd, gcl, ppk, metA, ftsZ, relA and metG for 30 O26 STEC strains have previously been sequenced, and comparative analyses to O157 distinguished these two serogroups. To screen these loci for serogroup-specific traits within a broader range of clinically significant serogroups, DNA sequences were obtained for 19 strains of 10 additional STEC serogroups. Unique alleles were observed at the gnd locus for each examined STEC serogroup, and this correlation persisted when comparative analyses were extended to 144 gnd sequences from 26 O-serogroups (comprising 42 O : H-serotypes). These included O157, O121, O103, O26, O5 : non-motile (NM), O145 : NM, O113 : H21, O111 : NM and O117 : H7 STEC; and furthermore, non-toxin encoding O157, O26, O55, O6 and O117 strains encoded distinct gnd alleles compared to STEC strains of the same serogroup. DNA sequencing of a 643 bp region of gnd was, therefore, sufficient to minimally determine the O-antigen of STEC through molecular means, and the location of gnd next to the O-antigen gene cluster offered additional support for the co-inheritance of these determinants. The gnd DNA sequence-based serogrouping method could improve the typing capabilities for STEC in clinical laboratories, and was used successfully to characterize O121 : H19, O26 : H11 and O177 : NM clinical isolates prior to serological confirmation during outbreak investigations.

scholarly journals Association of Nucleotide Polymorphisms within the O-Antigen Gene Cluster of Escherichia coli O26, O45, O103, O111, O121, and O145 with Serogroups and Genetic Subtypes

2012 ◽  
Vol 78 (18) ◽  
pp. 6689-6703 ◽  
Author(s):  
Keri N. Norman ◽  
Nancy A. Strockbine ◽  
James L. Bono
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Dna Sequence ◽  
Shiga Toxin ◽  
Severe Disease ◽  
The United States ◽  
Effective Control ◽  
Nucleotide Polymorphisms ◽  
Antigen Gene ◽  
O Antigen

ABSTRACTShiga toxin-producingEscherichia coli(STEC) strains are important food-borne pathogens capable of causing hemolytic-uremic syndrome. STEC O157:H7 strains cause the majority of severe disease in the United States; however, there is a growing concern for the amount and severity of illness attributable to non-O157 STEC. Recently, the Food Safety and Inspection Service (FSIS) published the intent to regulate the presence of STEC belonging to serogroups O26, O45, O103, O111, O121, and O145 in nonintact beef products. To ensure the effective control of these bacteria, sensitive and specific tests for their detection will be needed. In this study, we identified single nucleotide polymorphisms (SNPs) in the O-antigen gene cluster that could be used to detect STEC strains of the above-described serogroups. Using comparative DNA sequence analysis, we identified 22 potentially informative SNPs among 164 STEC and non-STEC strains of the above-described serogroups and designed matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) assays to test the STEC allele frequencies in an independent panel of bacterial strains. We found at least one SNP that was specific to each serogroup and also differentiated between STEC and non-STEC strains. Differences in the DNA sequence of the O-antigen gene cluster corresponded well with differences in the virulence gene profiles and provided evidence of different lineages for STEC and non-STEC strains. The SNPs discovered in this study can be used to develop tests that will not only accurately identify O26, O45, O103, O111, O121, and O145 strains but also predict whether strains detected in the above-described serogroups contain Shiga toxin-encoding genes.

scholarly journals Evidence for Contemporary Switching of the O-Antigen Gene Cluster between Shiga Toxin-Producing Escherichia coli Strains Colonizing Cattle

2017 ◽  
Vol 8 ◽  
Author(s):  
Lutz Geue ◽  
Christian Menge ◽  
Inga Eichhorn ◽  
Torsten Semmler ◽  
Lothar H. Wieler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Shiga Toxin ◽  
Antigen Gene ◽  
O Antigen

DNA sequence of theEscherichia coliO103 O antigen gene cluster and detection of enterohemorrhagicE. coliO103 by PCR amplification of thewzxandwzygenes

2005 ◽  
Vol 51 (6) ◽  
pp. 515-522 ◽  
Author(s):  
Pina M Fratamico ◽  
Chitrita DebRoy ◽  
Terence P Strobaugh, Jr. ◽  
Chin-Yi Chen
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Gene Cluster ◽  
Dna Sequence ◽  
Shiga Toxin ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Pcr Assays ◽  
Pcr Targeting

Escherichia coli serogroup O103 has been associated with gastrointestinal illness and hemolytic uremic syndrome. To develop PCR-based methods for detection and identification of this serogroup, the DNA sequence of the 12 033-bp region containing the O antigen gene cluster of Escherichia coli O103 was determined. Of the 12 open reading frames identified, the E. coli O103 wzx (O antigen flippase) and wzy (O antigen polymerase) genes were selected as targets for development of both conventional and real-time PCR assays specific for this serogroup. In addition, a multiplex PCR targeting the Shiga toxin (Stx) 1 (stx1), Shiga toxin 2 (stx2), wzx, and wzy genes was developed to differentiate Stx-producing E. coli O103 from non-toxigenic strains. The PCR assays can be employed to identify E. coli serogroup O103, replacing antigen-based serotyping, and to potentially detect the organism in food, fecal, or environmental samples.Key words: real-time polymerase chain reaction, E. coli typing, E. coli O103, O antigen DNA sequence.

Identification of Escherichia coli O-serogroups by restrictionof the amplified O-antigen gene cluster (rfb-RFLP)

2000 ◽  
Vol 151 (8) ◽  
pp. 639-654 ◽  
Author(s):  
Roney S. Coimbra ◽  
Francine Grimont ◽  
Pascal Lenormand ◽  
Pierre Burguière ◽  
Lothar Beutin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Antigen Gene ◽  
O Antigen

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 Structure and gene cluster of the O antigen of Escherichia coli L-19, a candidate for a new O-serogroup

Microbiology ◽  
2014 ◽  
Vol 160 (9) ◽  
pp. 2102-2107 ◽  
Author(s):  
Evelina L. Zdorovenko ◽  
Lyudmila D. Varbanets ◽  
Bin Liu ◽  
Olga A. Valueva ◽  
Quan Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Bacterial Cells ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Conserved Genes ◽  
Specific Polysaccharide ◽  
Phenol Water ◽  
C Nmr

Escherichia coli L-19 isolated from a healthy individual did not agglutinate with any of 21 polyvalent antisera that cover 174 E. coli O-serogroups. The strain was studied in respect to the O-antigen (O-specific polysaccharide, OPS) structure and genetics. The LPS was isolated by phenol–water extraction of bacterial cells and cleaved by mild acid hydrolysis to yield the OPS. The OPS was studied by sugar and methylation analyses, along with 1D and 2D 1H and 13C NMR spectroscopy. The established structure of the linear tetrasaccharide repeating unit was found to be unique among known bacterial polysaccharide structures. A peculiar component of the L-19 OPS was an amide of glucuronic acid with 2-amino-1,3-propanediol (2-amino-2-deoxyglycerol) (GroN). The O-antigen gene cluster of L-19 between the conserved genes galF and gnd was sequenced, and gene functions were tentatively assigned by a comparison with sequences in the available databases and found to be in agreement with the OPS structure. Except for putative genes for synthesis and transfer of GroN, the sequences in the L-19 O-antigen gene cluster were little related to those of reference strains of the 174 known E. coli O-serogroups. The data obtained suggest that L-19 can be considered as a candidate for a new E. coli O-serogroup.

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