Deletions of chromosomal regions coding for fimbriae and hemolysins occur in vitro and in vivo in various extra intestinal Escherichia coli isolates

Hacker, Jörg; Bender, Larisa; Ott, Manfred; Wingender, Jochen; Lund, B; Marre, R.; Goebel, Werner

doi:10.1016/0882-4010(90)90048-u

Cited by 276 publications

(213 citation statements)

References 35 publications

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“…Evidence supports the idea that PAIs are considered genetic units horizontally transferred through bacterial species during evolution (11). PAIs have common features including a preference for insertion at tRNA sites and atypical GC content (9,10). On the other hand, it has been suggested that operons are also mobile elements originated by horizontal transfer events (8).…”

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confidence: 62%

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A genomic population genetics analysis of the pathogenic enterocyte effacement island in Escherichia coli : The search for the unit of selection

Melgoza‐Castillo

Eguiarte

Souza

2005

Proc. Natl. Acad. Sci. U.S.A.

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Comparative genomic analysis is a powerful tool for understanding the history and organization of complete genomes. The mathematical tools of population genetics combined with genomic analysis provide a powerful approach to dissect heterogeneities in genome evolution. This study presents a hierarchical analysis of the enterocyte and effacement island (35 kb), which is found in the enteropathogenic and enterohemorrhagic strains in Escherichia coli and in Citrobacter rodentium. The locus of enterocyte and effacement in E. coli is considered to be a clonal unit inside a clonal organism and is expected to evolve as a single unit. This analysis examines the clonal assumption by determining genetic diversity, GC content, and the substitution rates at the different functional levels of (i) the complete pathogenic island, (ii) the five operons in which the island is organized, and (iii) for each of the individual 41 genes that comprise the locus. We find that there is a conserved region that is composed of genes that belong to the type III secretion system and that may be products of horizontal transfer. A more diverse region is composed of genes for secreted proteins and genes that we infer to be original components of the E. coli genome. This genetic mosaic seems to be differentially affected by selection and mutation. Our results suggest that recombination and selection may be breaking this structure so that different elements are, at best, weakly coupled in their evolution. These observations suggest that the units of selection are not the complete island, but rather, much smaller units that comprise the island.natural selection ͉ pathogenicity island ͉ positive Darwinian selection ͉ mutation ͉ GC content

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confidence: 62%

“…Typical examples of genomic islands are the pathogenic islands (PAIs) present in pathogenic bacteria that form the principal molecular component responsible for the development of a specific disease (9)(10)(11). Evidence supports the idea that PAIs are considered genetic units horizontally transferred through bacterial species during evolution (11).…”

mentioning

confidence: 87%

A genomic population genetics analysis of the pathogenic enterocyte effacement island in Escherichia coli : The search for the unit of selection

Melgoza‐Castillo

Eguiarte

Souza

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…Further studies revealed that additional genes involved in uropathogenicity are located on those islands (e.g. determinants coding for P fimbriae), which were consecutively renamed 'pathogenicity islands' (Hacker et a/., 1990;Blum etal., 1994). As the term 'pathogenicity island' (Pai) has become increasingly popular (Falkow, 1996;Lee, 1996;Groisman and Ochman, 1996), it is necessary to develop a precise definition.…”

Section: Definition Of Pathogenicity Islandsmentioning

confidence: 99%

Pathogenicity islands of virulent bacteria: structure, function and impact on microbial evolution

Hacker¹,

Blum-Oehler²,

Mühldorfer³

et al. 1997

Molecular Microbiology

1,016

738

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Summary Virulence genes of pathogenic bacteria, which code for toxins, adhesins, invasins or other virulence factors, may be located on transmissible genetic elements such as transposons, plasmids or bacteriophages. In addition, such genes may be part of particular regions on the bacterial chromosome, termed‘pathogenicity islands’(Pais). Pathogenicity islands are found in Gram‐negative as well as in Gram‐positive bacteria. They are present in the genome of pathogenic strains of a given species but absent or only rarely present in those of non‐pathogenic variants of the same or related species. They comprise large DNA regions (up to 200 kb of DNA) and often carry more than one virulence gene, the G+C contents of which often differ from those of the remaining bacterial genome. In most cases, Pais are flanked by specific DNA sequences, such as direct repeats or insertion sequence (IS) elements. In addition, Pais of certain bacteria (e.g. uropathogenic Escherichia coli, Yersinia spp., Helicobacter pylori) have the tendency to delete with high frequencies or may undergo duplications and amplifications. Pais are often associated with tRNA loci, which may represent target sites for the chromosomal integration of these elements. Bacteriophage attachment sites and cryptic genes on Pais, which are homologous to phage integrase genes, plasmid origins of replication or IS elements, indicate that these particular genetic elements were previously able to spread among bacterial populations by horizontal gene transfer, a process known to contribute to microbial evolution.

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“…These, may have been acquired by plasmids and bacteriophages and can encode the molecular arsenal that enables these strains to colonize the urinary tract and survive in extraintestinal sites. In UPEC, the most studied PAIs are: PAI I and II identified in E. coli J96 and CFT073, and PAI I and IV in E. coli, with PAI IV 536 being more common in UPEC [6,7]. The presence of PAIs in UPEC is a feature associated with clinically severe forms of infection [8].…”

Section: Introductionmentioning

confidence: 99%

Presence of virulence genes and pathogenicity islands in extraintestinal pathogenic Escherichia coli isolates from Brazil

Cyoia

Rodrigues

Nishio

et al. 2015

J Infect Dev Ctries

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Introduction: Extraintestinal pathogenic Escherichia coli (ExPEC) is associated with various diseases such as urinary tract infections, neonatal meningitis and septicemia. There are many virulence factors (VF) encoded by genes in ExPEC, including papC, papG, ecpA, iroN, fyuA, iutA, ompTp, tsh, hlyF, hlyA and iss. These virulence genes may be present in pathogenicity islands (PAI) or plasmids. Methodology: In this study, we analyzed the presence of VF encoding genes, PAI sequences and phylogenetic groups of 96 ExPEC strains isolated from the urine and blood of patients at the University Hospital of Londrina, and we compared them with 50 faecal commensal strains from healthy individuals. Results: The VF fyuA (65.60%) was detected in pathogenic strains and commensal strains (46%). A comparison of the distribution of ExPEC and commensal strains in the phylogenetic groups showed that more ExPEC strains belonged to group B2 whereas more of the commensal isolates belonged to group A. The distribution of the seven PAI sequences between commensal strains and ExPEC strains showed that PAI IV 536 was common in both ExPEC and commensal isolates. Conclusions: These results showed that the ExPEC strains that belonged to group B2 had more PAI sequences compared to those of the other groups, especially group B1, which had virulence genes but the lowest percentage of PAI sequences, which leads us to conclude that the virulence of ExPEC strains characterized as B2 is likely attributed to PAI encoded genes, whereas the virulence of ExPEC strains belonging to phylogenetic group B1 is likely due to plasmid encoded virulence genes.

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Deletions of chromosomal regions coding for fimbriae and hemolysins occur in vitro and in vivo in various extra intestinal Escherichia coli isolates

Cited by 276 publications

References 35 publications

A genomic population genetics analysis of the pathogenic enterocyte effacement island in Escherichia coli : The search for the unit of selection

A genomic population genetics analysis of the pathogenic enterocyte effacement island in Escherichia coli : The search for the unit of selection

Pathogenicity islands of virulent bacteria: structure, function and impact on microbial evolution

Presence of virulence genes and pathogenicity islands in extraintestinal pathogenic Escherichia coli isolates from Brazil

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