The conserved portion of the putative virulence region contributes to virulence of avian pathogenic Escherichia coli

Tivendale, Kelly A.; Noormohammadi, Amir H.; Allen, Joanne L.; Browning, Glenn F.

doi:10.1099/mic.0.023143-0

Cited by 29 publications

(30 citation statements)

References 32 publications

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“…6). To date, four ColBM plasmids have been sequenced, including three from APEC strains (pAPEC-O1-ColBM, pVM01, and pAPEC-O103-ColBM) (Table 3) (87,181) and one from an MDR E. coli strain isolated from a coastal environment (pSMS35_130) ( linkage of MDR-encoding regions with the ColV-encoded PAI is particularly disturbing, since it provides a means for the selection of highly virulent strains through the use of antibiotics. pCVM29188_146 harbors typical ColV-associated virulence genes but also contains Tn10 downstream of the F transfer region, an atypical region for accessory components (Fig.…”

Section: Colv and Colbm Plasmidsmentioning

confidence: 99%

Pathogenomics of the Virulence Plasmids ofEscherichia coli

Johnson

Nolan

2009

Microbiol Mol Biol Rev

374

369

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SUMMARY Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. coli virulence plasmids exist, including those essential for the virulence of enterotoxigenic E. coli, enteroinvasive E. coli, enteropathogenic E. coli, enterohemorrhagic E. coli, enteroaggregative E. coli, and extraintestinal pathogenic E. coli. Despite their diversity, these plasmids belong to a few plasmid backbones that present themselves in a conserved and syntenic manner. Thanks to some recent research, including sequence analysis of several representative plasmid genomes and molecular pathogenesis studies, the evolution of these virulence plasmids and the implications of their acquisition by E. coli are now better understood and appreciated. Here, work involving each of the E. coli virulence plasmid types is summarized, with the available plasmid genomic sequences for several E. coli pathotypes being compared in an effort to understand the evolution of these plasmid types and define their core and accessory components.

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Section: Colv and Colbm Plasmidsmentioning

confidence: 99%

Pathogenomics of the Virulence Plasmids ofEscherichia coli

Johnson

Nolan

2009

Microbiol Mol Biol Rev

374

369

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“…80-kb region enriched in virulence-associated loci, including four iron acquisition systems (iutA, iucABCD, sitABCD, iroBCDN), tsh, iss, and other candidate virulence genes (44). This region also appears to contribute to air sac colonization and the induction of pathology by an O nontypeable:H28 APEC field isolate in poultry (45). Of the other plasmids found in 7122, pChi7122-2 is an IncFII plasmid that encodes an ABC iron transport system (eitABCD), whereas pChi7122-3 (IncI2) carries a putative type IV fimbrial locus (43).…”

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confidence: 99%

Sequencing and Functional Annotation of Avian Pathogenic Escherichia coli Serogroup O78 Strains Reveal the Evolution of E. coli Lineages Pathogenic for Poultry via Distinct Mechanisms

et al. 2013

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f Avian pathogenic Escherichia coli (APEC) causes respiratory and systemic disease in poultry. Sequencing of a multilocus sequence type 95 (ST95) serogroup O1 strain previously indicated that APEC resembles E. coli causing extraintestinal human diseases. We sequenced the genomes of two strains of another dominant APEC lineage (ST23 serogroup O78 strains 7122 and IMT2125) and compared them to each other and to the reannotated APEC O1 sequence. For comparison, we also sequenced a human enterotoxigenic E. coli (ETEC) strain of the same ST23 serogroup O78 lineage. Phylogenetic analysis indicated that the APEC O78 strains were more closely related to human ST23 ETEC than to APEC O1, indicating that separation of pathotypes on the basis of their extraintestinal or diarrheagenic nature is not supported by their phylogeny. The accessory genome of APEC ST23 strains exhibited limited conservation of APEC O1 genomic islands and a distinct repertoire of virulence-associated loci. In light of this diversity, we surveyed the phenotype of 2,185 signature-tagged transposon mutants of 7122 following intra-air sac inoculation of turkeys. This procedure identified novel APEC ST23 genes that play strain-and tissue-specific roles during infection. For example, genes mediating group 4 capsule synthesis were required for the virulence of 7122 and were conserved in IMT2125 but absent from APEC O1. Our data reveal the genetic diversity of E. coli strains adapted to cause the same avian disease and indicate that the core genome of the ST23 lineage serves as a chassis for the evolution of E. coli strains adapted to cause avian or human disease via acquisition of distinct virulence genes. Avian pathogenic Escherichia coli (APEC) imposes substantial economic and welfare costs on poultry producers worldwide. Respiratory infections typically involve inflammation of the air sacs and lung and may spread to visceral organs, causing perihepatitis, pericarditis, peritonitis, salpingitis, and sepsis (1). A need exists for effective cross-protective vaccines to control APEC in poultry, since autologous bacterins confer limited serotype-specific protection, and control via antibiotics is hindered by resistance and restrictions on prophylaxis. Diverse serotypes are associated with disease, and the molecular mechanisms underlying mucosal colonization and systemic translocation are ill defined. Serogroup O1, O2, and O78 strains are frequently isolated from diseased poultry and mostly belong to multilocus sequence types 95 and 23 (ST95 and ST23) (http://mlst.ucc.ie/mlst/dbs/Ecoli), as evidenced by recent surveys in chickens (2) and turkeys (3). The genetic traits that define the APEC pathotype and the extent of inter-and intra-ST and serogroup diversity are incompletely understood.Sequencing of the complete genome of a ST95 strain of APEC serotype O1:K1:H7 (APEC O1) revealed that it is closely related to extraintestinal pathogenic E. coli (ExPEC) strains associated with human urinary tract infections (4). This is further evident from multilocus sequence ...

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“…Carraminana et al [6] reported that 40% of the antibiotics produced in the United States were used in stock feeds. The widespread use of various antibiotics for treating animal infections has created antibiotic resistant bacterial strains [7] [8]. Antimicrobial resistance is one of our most serious health threats.…”

Section: Introductionmentioning

confidence: 99%