Pyrosequencing of the Vir plasmid of necrotoxigenic Escherichia coli

Johnson, Timothy J.; DebRoy, Chitrita; Belton, Shayla; Williams, Michele L.; Lawrence, Mark L.; Nolan, Lisa K.; Thorsness, Jessica L.

doi:10.1016/j.vetmic.2009.12.022

Cited by 22 publications

(26 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The IS21 element has been reported to be located close to a cdt-III gene in a pVir plasmid in E. coli (46) but is present in a different position and with the opposite orientation. IS21 has also been found in P2-like phage ⌽CTX in Pseudomonas aeruginosa (31) but without the cdt operon.…”

Section: Discussionmentioning

confidence: 99%

Evolution of a Self-Inducible Cytolethal Distending Toxin Type V-Encoding Bacteriophage from Escherichia coli O157:H7 to Shigella sonnei

Allué-Guardia

Imamovic

Muniesa

2013

J Virol

View full text Add to dashboard Cite

Some cdt genes are located within the genome of inducible or cryptic bacteriophages, but there is little information about the mechanisms of cdt transfer because of the reduced number of inducible Cdt phages described. In this study, a new self-inducible Myoviridae Cdt phage (⌽AA91) was isolated from a nonclinical O157:H7 Shiga toxin-producing Escherichia coli strain and was used to lysogenize a cdt-negative strain of Shigella sonnei. We found that the phage induced from S. sonnei (⌽AA91-ss) was not identical to the original phage. ⌽AA91-ss was used to infect a collection of 57 bacterial strains, was infectious in 59.6% of the strains, and was able to lysogenize 22.8% of them. The complete sequence of ⌽AA91-ss showed a 33,628-bp genome with characteristics of a P2-like phage with the cdt operon located near the cosR site. We found an IS21 element composed of two open reading frames inserted within the cox gene of the phage, causing gene truncation. Truncation of cox does not affect lytic induction but could contribute to phage recombination and generation of lysogens. The IS21 element was not present in the ⌽AA91 phage from E. coli, but it was incorporated into the phage genome after its transduction in Shigella. This study shows empirically the evolution of temperate bacteriophages carrying virulence genes after infecting a new host and the generation of a phage population with better lysogenic abilities that would ultimately lead to the emergence of new pathogenic strains.

show abstract

Section: Discussionmentioning

confidence: 99%

Evolution of a Self-Inducible Cytolethal Distending Toxin Type V-Encoding Bacteriophage from Escherichia coli O157:H7 to Shigella sonnei

Allué-Guardia

Imamovic

Muniesa

2013

J Virol

View full text Add to dashboard Cite

show abstract

“…Detection of F17e-A and F17-G3 variants was then performed by PCR with specific primers (10), using E. coli MHI813 (32) and MG1655 as positive and negative controls, respectively. A search for cnf2 and cdtIII in the F17e-A-and F17-G3-positive isolates was performed by PCR (25), using E. coli strains 6.0900 and MG1655 as positive and negative controls, respectively. The oligonucleotides used are listed in Table 1.…”

Section: Determination Of F17e-a F17-g3 Cnf2 and Cdtiii Producersmentioning

confidence: 99%

“…Accordingly, the Vir plasmid was initially designated the molecular support for both toxic and adhesive transmissible properties referred to as the "Vir phenotype" in E. coli isolates from septicemic calves and lambs (6,(20)(21)(22). Later on, the Vir plasmid was reported to propagate the cnf2 and f17A genes in NTEC2 cattle isolates (23,24) and other genes, such as cdtIII (19,25). The role of such Vir-like plasmids was also investigated in experimental calf models (26).…”

mentioning

confidence: 99%

Divergent Evolution of the repFII Replicon of IncF Plasmids Carrying Cytotoxic Necrotizing Factor cnf2 , Cytolethal Distending Toxin cdtIII , and f17Ae Fimbrial Variant Genes in Type 2 Necrotoxigenic Escherichia coli Isolates from Calves

Bihannic

Haenni²,

Oswald

et al. 2016

Appl Environ Microbiol

View full text Add to dashboard Cite

dAmong the pathovars of Escherichia coli in cattle, necrotoxigenic E. coli (NTEC) is defined by the production of cytotoxic necrotizing factors (CNFs). In particular, type 2 NTEC (NTEC2) strains are frequent in diarrheic and septicemic calves and usually coproduce CNF type 2 (CNF2), cytolethal distending toxin type III (CDTIII), and fimbrial adhesins of the F17 family, whose genetic determinants have frequently been reported on the same Vir-like plasmid. In this study, we investigated the genetic environment of the cnf2, f17Ae, and cdtIII genes in a collection of fecal E. coli isolates recovered from 484 French and 58 Iranian calves. In particular, we highlighted the spread of cnf2, f17Ae, and cdtIII on similar 150-kb IncF plasmids harboring the newly assigned repFII replicon allele F74 in NTEC2 isolates. Interestingly, this 150-kb IncF plasmid differed from the 140-kb IncF plasmid harboring the newly assigned repFII replicon allele F75 and carrying cnf2 alone. These results suggest two divergent lineages of cnf2-carrying IncF plasmids depending on the presence of the f17Ae and cdtIII genes. This partition was observed in E. coli strains of unrelated backgrounds, suggesting two different evolutionary paths of cnf2-carrying IncF plasmids rather than divergent evolutions of NTEC2 clones. The driving forces for such divergent evolutions are not known, and further studies are required to clarify the selection of plasmid subtypes spreading virulence determinants in E. coli, in particular, plasmids of the IncF family. Escherichia coli is considered a dominant member of the normal microflora of mammals but may also be responsible for intestinal and extraintestinal infections (1). Accordingly, several pathovars of E. coli have been reported over time both in humans and in animals (1, 2). In general, those infections result from a combination of host susceptibility and biological functions expressed by the pathogenic E. coli strain, such as an enhanced ability to colonize the host or the production of toxigenic factors.To adhere to host cells, pathogenic E. coli strains usually produce fimbrial or afimbrial adhesins. In cattle, E. coli isolates from diarrheic and septicemic calves often produce F17 fimbriae (3, 4), which bind N-acetyl-D-glucosamine (GlcNAc)-containing receptors present on host intestinal epithelial cells (4, 5). F17 fimbriae consist of fine filamentous heteropolymers composed of two main subunits: the pilin F17-A subunit, which forms the bulk of the fimbriae, and the adhesin F17-G subunit (4). Several variants have been reported: F17a-A, F17b-A, F17c-A, F17d-A, F17e-A, and F17f-A for the F17-A pilin (6-10) and F17-G1, F17-G2, and F17-G3 for the F17-G adhesin (10, 11). In particular, the recently reported F17e-A variant was abundantly found in E. coli isolates from diarrheic calves in Iran and was found to be associated with F17-G3 on a pathogenicity or a fitness island in Shiga toxin-producing E. coli (STEC) strain MHI813 (10).Among the virulence determinants reported in cattle-pathogenic E. coli strains...

show abstract

“…CDTs are quite disseminated in several species and so far in E. coli fi ve genotypes were identifi ed (reviewed by Tóth and Sváb) [7]. In all cases the cdtABC operons were either part of the genome of an inducible converting lambdoid prophage [8], a defective P-2 like prophage [9], a large plasmid [10], as part of a PAI [11] or framed with lambdoid phage genes [12].…”

Section: Introductionmentioning

confidence: 99%

The cytolethal distending toxin-IV cdt coding region in an avian pathogenic Escherichia coli (APEC) strain shows instability and irregular excision pattern

Tóth

Schneider

2015

Acta Microbiologica et Immunologica Hungarica

View full text Add to dashboard Cite

Cytolethal distending toxins (CDT) represent an emerging toxin family, widely distributed among pathogenic bacteria. The cdtABC genes in E. coli are either part of the genome of prophages, plasmid or pathogenicity island. In order to investigate the stability and the transfer potential of cdt-IV genes cdtB gene was replaced by chloramphenicol (Cm) resistance encoding cat gene in the avian pathogenic E. coli (APEC) strain E250. After consecutive passages in non-selective medium at 37 °C 7.6% (219/2900) of the investigated colonies of E250::cat strain became Cm-sensitive (Cm S ). To reveal deletion mechanism 177 Cm S colonies were investigated for presence of cdtA, cdtC and cdtC associated gene by PCR. One hundred and sixteen colonies of the Cm S colonies (65.5%) showed partial or complete deletion in the cdt-IV region. Progressive loss of the upstream genes of the cdt cluster in E250 compared to other CDT-IV producing APEC strains and the fact that all the potential deletion patterns were identifi ed, suggests the presence of an unstable hitherto unknown genomic region. The failure of in vitro transfer of cdt genes into a porcine EPEC E. coli strain suggests that the deletion of cdt-IV fl anking genes alone do not promote the spread of cdt-IV.

show abstract

Pyrosequencing of the Vir plasmid of necrotoxigenic Escherichia coli

Cited by 22 publications

References 27 publications

Evolution of a Self-Inducible Cytolethal Distending Toxin Type V-Encoding Bacteriophage from Escherichia coli O157:H7 to Shigella sonnei

Evolution of a Self-Inducible Cytolethal Distending Toxin Type V-Encoding Bacteriophage from Escherichia coli O157:H7 to Shigella sonnei

Divergent Evolution of the repFII Replicon of IncF Plasmids Carrying Cytotoxic Necrotizing Factor cnf2 , Cytolethal Distending Toxin cdtIII , and f17Ae Fimbrial Variant Genes in Type 2 Necrotoxigenic Escherichia coli Isolates from Calves

The cytolethal distending toxin-IV cdt coding region in an avian pathogenic Escherichia coli (APEC) strain shows instability and irregular excision pattern

Contact Info

Product

Resources

About