Unusual Genotype of a Uropathogenic Escherichia coli Strain Assigned to the B2 Phylogenetic Group

Center of Pharmaceutical Sciences, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.
Journal of clinical microbiology (Impact Factor: 3.99). 06/2011; 49(8):3105-6. DOI: 10.1128/JCM.00585-11
Source: PubMed


Extraintestinal pathogenic Escherichia coli (ExPEC) cause infections such as urinary tract infections, septicemia and meningitis.…

Download full-text


Available from: Nuno Mendonça, Jul 23, 2014
20 Reads
  • Source
    • "In order to determine the impact of the mutations we compared Doumith's multiplex PCR protocol [5] updating the design of the primers used in the 2000 Clermont's method [4], reducing unspecific annealing and promoting specific amplification, thus improving coverage. Non-specific amplifications (as for an acetyl-hydrolase gene) using conventional Clermont's protocol have been reported for B1 isolates [22], but this protocol has also occasionally failed in the amplification of chuA and/or yjaA [5], [23], [24], [25], [26]. In fact, in our series Clermont's multiplex PCR approach provides a worse assignment (14.0% "
    [Show abstract] [Hide abstract]
    ABSTRACT: The characterization of population structures plays a main role for understanding outbreaks and the dynamics of bacterial spreading. In Escherichia coli, the widely used combination of multiplex-PCR scheme together with goeBURST has some limitations. The purpose of this study is to show that the combination of different phylogenetic approaches based on concatenated sequences of MLST genes results in a more precise assignment of E. coli phylogenetic groups, complete understanding of population structure and reconstruction of ancestral clones. A collection of 80 Escherichia coli strains of different origins was analyzed following the Clermont and Doumith's multiplex-PCR schemes. Doumith's multiplex-PCR showed only 1.7% of misassignment, whereas Clermont's-2000 protocol reached 14.0%, although the discrepancies reached 30% and 38.7% respectively when recombinant C, F and E phylogroups were considered. Therefore, correct phylogroup attribution is highly variable and depends on the clonal composition of the sample. As far as population structure of these E. coli strains, including 48 E. coli genomes from GenBank, goeBURST provides a quite dispersed population structure; whereas NeighborNet approach reveals a complex population structure. MLST-based eBURST can infer different founder genotypes, for instance ST23/ST88 could be detected as the founder genotypes for STC23; however, phylogenetic reconstructions might suggest ST410 as the ancestor clone and several evolutionary trajectories with different founders. To improve our routine understanding of E. coli molecular epidemiology, we propose a strategy based on three successive steps; first, to discriminate three main groups A/B1/C, D/F/E and B2 following Doumith's protocol; second, visualization of population structure based on MLST genes according to goeBURST, using NeighborNet to establish more complex relationships among STs; and third, to perform, a cost-free characterization of evolutionary trajectories in variants emerging along the clonal expansion using parsimony methods of phylogenetic analysis.
    PLoS ONE 08/2014; 9(8):e105395. DOI:10.1371/journal.pone.0105395 · 3.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Escherichia coli represents a major cause of morbidity and mortality worldwide. The treatment of E. coli infections is now threatened by the emergence of antimicrobial resistance. The dissemination of resistance is associated with genetic mobile elements, such as plasmids, that may also carry virulence determinants. A proficient pathogen should be virulent, resistant to antibiotics, and epidemic. However, the interplay between resistance and virulence is poorly understood. This review aims to critically discuss the association and linked transmission of both resistance and virulence traits in strains from extraintestinal infections in E. coli, and intestinal pathotypes. Despite the numerous controversies on this topic, findings from research published to date indicate that there is a link between resistance and virulence, as illustrated by the successful E. coli ST131 epidemic clone. Perhaps the most commonly accepted view is that resistance to quinolones is linked to a loss of virulence factors. However, the low virulent phylogenetic groups might be more prone to acquire resistance to quinolones. Specific characteristics of the E. coli genome that have yet to be identified may contribute to such genetic linkages. Research based on bacterial populations is sorely needed to help understand the molecular mechanisms underlying the association between resistance and virulence, that, in turn, may help manage the future disseminations of infectious diseases in their entirety.
    Virulence 01/2012; 3(1):18-28. DOI:10.4161/viru.3.1.18382 · 4.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Using data from whole-genome projects, an updated multiplex PCR strategy was developed to assign Escherichia coli isolates rapidly to major phylogenetic groups. This assay accommodates sequence variations detected within target sequences, thereby increasing sensitivity and reliability. It was validated using 185 isolates of known sequence types and showed improved congruence with multilocus sequence typing data.
    Journal of clinical microbiology 07/2012; 50(9):3108-10. DOI:10.1128/JCM.01468-12 · 3.99 Impact Factor
Show more