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The GimA locus of extraintestinal pathogenic E. coli: does reductive evolution correlate with habitat and pathotype?
Timo Homeier1, Torsten Semmler, Lothar H Wieler
1Institute for Microbiology and Epizootics, Veterinary Faculty, Free University Berlin, Berlin, Germany.
Plos One
|June 8, 2010
Summary
The GimA genomic region, containing the IbeA gene, is primarily found in extraintestinal pathogenic E. coli (ExPEC) strains of phylogenetic group B2. Its presence and form (complete or remnant) correlate with specific ExPEC pathotypes, suggesting an ancestral role rather than a mobile genomic island.
Area of Science:
- Microbiology
- Genomics
- Evolutionary Biology
Background:
- The IbeA gene, located on the GimA genomic island, is crucial for the pathogenesis of extraintestinal pathogenic E. coli (ExPEC) strains.
- ExPEC pathotypes include newborn meningitic E. coli (NMEC) and avian pathogenic E. coli (APEC), highlighting the importance of understanding GimA's role.
Purpose of the Study:
- To determine the phylogeny and genomic island characteristics of the GimA region.
- To investigate the distribution and evolutionary patterns of GimA in various E. coli pathotypes.
Main Methods:
- Analysis of GimA insertion loci using Long Range PCR and DNA-DNA hybridization.
- Examination of 410 E. coli isolates (APEC, NMEC, UPEC, SEPEC, fecal, ECOR collection) for GimA presence and structure.
- Phylogenetic analysis of GimA and IbeA sequences, compared with Multi Locus Sequence Typing (MLST) data.
Main Results:
- Three GimA patterns were identified: complete (approx. 20.3 kb), absent, and a 342 bp remnant.
- GimA was predominantly found in E. coli phylogenetic group B2 strains.
- Complete GimA was more frequent in APEC and NMEC, while GimA remnants were associated with UPEC strains.
Conclusions:
- GimA appears to be an ancestral component of E. coli phylogenetic group B2, not a typical mobile genomic island.
- Genomic rearrangements within GimA, leading to complete and remnant forms, reflect reductive evolution.
- The distribution patterns of GimA variants correlate with specific ExPEC pathotypes, offering insights into their evolution.
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