Genetic structure and chromosomal integration site of the cryptic prophage CP-1639 encoding Shiga toxin 1

Creuzburg, Kristina; Köhler, Bernd; Hempel, H C; Schreier, Peter; Jacobs, Enno; Schmidt, Herbert

doi:10.1099/mic.0.27632-0

Cited by 32 publications

(25 citation statements)

References 72 publications

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“…In that report, the majority of the stx-negative/eae-positive isolates belonged to serogroups O26, O103, O145, and O157:H7/NM, but no stx-negative/eae-positive E. coli O111 isolates were reported. The absence of stx-negative/eae-positive E. coli O111 isolates in the HUS patients may be explained by the fact that a majority of the EHEC O111 isolates possessed stx 1 solely or in combination with stx 2 (13), and the Stx1 prophage of EHEC O111 is thought to be defective, resulting in immobilization and stability in the EHEC chromosome (41). In contrast to a previous investigation (39) subcultures.…”

Section: Discussioncontrasting

confidence: 49%

Characterization of Enterohemorrhagic Escherichia coli O111 and O157 Strains Isolated from Outbreak Patients in Japan

et al. 2014

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In April and May 2011, there was a serious food-poisoning outbreak in Japan caused by enterohemorrhagic Escherichia coli (EHEC) strains O111:H8 and O157:H7 from raw beef dishes at branches of a barbecue restaurant. This outbreak involved 181 infected patients, including 34 hemolytic-uremic syndrome (HUS) cases (19%). Among the 34 HUS patients, 21 developed acute encephalopathy (AE) and 5 died. Patient stool specimens yielded E. coli O111 and O157 strains. We also detected both EHEC O111 stx 2 and stx-negative E. coli O111 strains in a stock of meat block from the restaurant. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analysis (MLVA) showed that the stx-negative E. coli O111 isolates were closely related to EHEC O111 stx 2 isolates. Although the EHEC O157 strains had diverse stx gene profiles (stx 1 , stx 2 , and stx 1 stx 2 ), the PFGE and MLVA analyses indicated that these isolates originated from a single clone. Deletion of the Stx2-converting prophage from the EHEC O111 stx 2 isolates was frequently observed during in vitro growth, suggesting that strain conversion from an EHEC O111 stx 2 to an stx-negative strain may have occurred during infection.

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Section: Discussioncontrasting

confidence: 49%

Characterization of Enterohemorrhagic Escherichia coli O111 and O157 Strains Isolated from Outbreak Patients in Japan

et al. 2014

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“…All strains were investigated for the insertion of foreign DNA in particular sites by PCR. Therefore, the known LEE and phage integration site genes selC, pheU, pheV, yehV, yecE, wrbA, ssrA, and z2577 (31,32,35,37,42) were amplified with oligonucleotides and PCR conditions given in Table 1. In addition, the presence of PAI I CL3 , the locus of proteolysis, and the sab gene (44)(45)(46) was detected by PCR with the oligonucleotides and PCR conditions given in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…Prophages are able to integrate into different chromosomal insertion sites dependent on the availability of their preferred site in the host strain (30,31). A number of target sites, such as yehV (32), yecE (33), wrbA (31,34), z2577 (35,36), ssrA (37), and sbcB (38), have been described.…”

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confidence: 99%

Phylogenetic and Molecular Analysis of Food-Borne Shiga Toxin-Producing Escherichia coli

Hauser

Mellmann

Semmler

et al. 2013

Appl Environ Microbiol

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e Seventy-five food-associated Shiga toxin-producing Escherichia coli (STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI I CL3 , and the autotransporter-encoding gene sabA was examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE), selC, pheU, and pheV, as well as the Stx phage integration sites yehV, yecE, wrbA, z2577, and ssrA, was analyzed. Moreover, the antibiotic resistance phenotypes of all STEC strains were determined. Multilocus sequence typing (MLST) was performed, and sequence types (STs) and sequence type complexes (STCs) were compared with those of 42 hemolytic-uremic syndrome (HUS)-associated enterohemorrhagic E. coli (HUSEC) strains. Besides 59 STs and 4 STCs, three larger clusters were defined in this strain collection. Clusters A and C consist mostly of highly pathogenic eae-positive HUSEC strains and some related food-borne STEC strains. A member of a new O26 HUS-associated clone and the 2011 outbreak strain E. coli O104:H4 were found in cluster A. Cluster B comprises only eae-negative food-borne STEC strains as well as mainly eae-negative HUSEC strains. Although food-borne strains of cluster B were not clearly associated with disease, serotypes of important pathogens, such as O91:H21 and O113:H21, were in this cluster and closely related to the food-borne strains. Clonal analysis demonstrated eight closely related genetic groups of food-borne STEC and HUSEC strains that shared the same ST and were similar in their virulence gene composition. These groups should be considered with respect to their potential for human infection.

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“…In contrast to many genetic elements that are frequently integrated within tRNA genes (19), Stx phages insert their DNA preferably into genes from the basic genetic equipment of the E. coli chromosome (20). Nine Stx phage insertion sites have been described, including wrbA, which codes for a tryptophan repressor-binding protein (21); yehV, which codes for a transcriptional regulator (22,23); yecE, whose function is unknown (24); sbcB, which produces an exonuclease (25,26); Z2577, which codes for an oxidoreductase (27); ssrA, which encodes a tmRNA (28,29); prfC, which encodes peptide chain release factor 3; argW, which codes for tRNA-Arg; and the torS-torT intergenic region (30)(31)(32). The ssrA gene is also known as an insertion site for EspK phages carrying the type III effector EspK-encoding gene (33).…”

mentioning

confidence: 99%

Diversity of Shiga Toxin-Producing Escherichia coli (STEC) O26:H11 Strains Examined via stx Subtypes and Insertion Sites of Stx and EspK Bacteriophages

Bonanno

Loukiadis

Mariani‐Kurkdjian

et al. 2015

Appl Environ Microbiol

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f Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen that may be responsible for severe human infections. Only a limited number of serotypes, including O26:H11, are involved in the majority of serious cases and outbreaks. The main virulence factors, Shiga toxins (Stx), are encoded by bacteriophages. Seventy-four STEC O26:H11 strains of various origins (including human, dairy, and cattle) were characterized for their stx subtypes and Stx phage chromosomal insertion sites. The majority of food and cattle strains possessed the stx 1a subtype, while human strains carried mainly stx 1a or stx 2a . The wrbA and yehV genes were the main Stx phage insertion sites in STEC O26:H11, followed distantly by yecE and sbcB. Interestingly, the occurrence of Stx phages inserted in the yecE gene was low in dairy strains. In most of the 29 stx-negative E. coli O26:H11 strains also studied here, these bacterial insertion sites were vacant. Multilocus sequence typing of 20 stx-positive or stx-negative E. coli O26: H11 strains showed that they were distributed into two phylogenetic groups defined by sequence type 21 (ST21) and ST29. Finally, an EspK-carrying phage was found inserted in the ssrA gene in the majority of the STEC O26:H11 strains but in only a minority of the stx-negative E. coli O26:H11 strains. The differences in the stx subtypes and Stx phage insertion sites observed in STEC O26:H11 according to their origin might reflect that strains circulating in cattle and foods are clonally distinct from those isolated from human patients.

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Genetic structure and chromosomal integration site of the cryptic prophage CP-1639 encoding Shiga toxin 1

Cited by 32 publications

References 72 publications

Characterization of Enterohemorrhagic Escherichia coli O111 and O157 Strains Isolated from Outbreak Patients in Japan

Characterization of Enterohemorrhagic Escherichia coli O111 and O157 Strains Isolated from Outbreak Patients in Japan

Phylogenetic and Molecular Analysis of Food-Borne Shiga Toxin-Producing Escherichia coli

Diversity of Shiga Toxin-Producing Escherichia coli (STEC) O26:H11 Strains Examined via stx Subtypes and Insertion Sites of Stx and EspK Bacteriophages

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