Escherichia coli K88 Interaction with IgA Oligosaccharides

Diarrhea from enterotoxigenic Escherichia coli (E. coli) expressing the K88 fimbrial adhesin causes high morbidity and mortality among newborn and weaned piglets. K88 fimbrial adhesins are surface filaments with lectin activity that recognize specific glycoconjugates (glycoproteins or glycolipids) on the surface of intestinal cells. Carbohydrates that compete for adhesion attachment could serve as an alternative for disease prevention. In this study, IgA, IgG and IgM oligosaccharides were tested to inhibit the adhesion of E. coli K88 to piglet mucins. Immunoglobulins were isolated from porcine serum by hydrophobic interaction chromatography (HIC) and purified by affinity chromatography. In vitro K88 adhesin interacts specifically with IgA oligosaccharides, but not with carbohydrates of IgG or IgM. Also IgA oligosaccharides partially inhibit the adherence of K88 strain to porcine intestinal mucins

Molecular and Genomic Characterization of Vibrio mimicus Isolated from a Frozen Shrimp Processing Facility in Mexico.

Vibrio mimicus is a gram-negative bacterium responsible for diseases in humans. Three strains of V. mimicus identified as V. mimicus 87, V. mimicus 92 and V. mimicus 93 were isolated from a shrimp processing facility in Guaymas, Sonora, Mexico. The strains were analyzed using several molecular techniques and according to the cluster analysis they were different, their similarities ranged between 51.3% and 71.6%. ERIC-PCR and RAPD (vmh390R) were the most discriminatory molecular techniques for the differentiation of these strains. The complete genomes of two strains (V. mimicus 87, renamed as CAIM 1882, and V. mimicus 92, renamed as CAIM 1883) were sequenced. The sizes of the genomes were 3.9 Mb in both strains, with 2.8 Mb in ChI and 1.1 Mb in ChII. A 12.7% difference was found in the proteome content (BLAST matrix). Several virulence genes were detected (e.g. capsular polysaccharide, an accessory colonization factor and genes involved in quorum-sensing) which were classified in 16 categories. Variations in the gene content between these genomes were observed, mainly in proteins and virulence genes (e.g., hemagglutinin, mobile elements and membrane proteins). According to these results, both strains were different, even when they came from the same source, giving an insight of the diversity of V. mimicus. The identification of various virulence genes, including a not previously reported V. mimicus gene (acfD) in ChI in all sequenced strains, supports the pathogenic potential of this species. Further analysis will help to fully understand their potential virulence, environmental impact and evolution

Maximum likelihood (ML) and Neighbor joining (NJ) phylogenetic trees of 28 core genome virulence genes.

<p>The ML and NL phylogenetic trees of both chromosomes of <i>V</i>. <i>mimicus</i> CAIM 1882, 1883, 602 and <i>V</i>. <i>mimicus</i> 451 were obtained using MEGA, where <i>V</i>. <i>cholerae</i> O1 biovar El Tor N16961 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144885#pone.0144885.ref034" target="_blank">34</a>] was used as outgroup.</p

BLAST matrix (proteome comparison) of <i>V</i>. <i>mimicus</i> 451, <i>V</i>. <i>mimicus</i> CAIM 602, <i>V</i>. <i>mimicus</i> CAIM 1882 and <i>V</i>. <i>mimicus</i> CAIM 1883.

<p>The BLAST matrix was obtained using CMG-biotools [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144885#pone.0144885.ref035" target="_blank">35</a>].</p

Genome Atlas obtained of <i>V</i>. <i>mimicus</i> CAIM 602 (green), CAIM 1882 (red), CAIM 1883 (blue) and <i>V</i>. <i>mimicus</i> 451 (as control strain).

<p>The atlas was constructed with GeneWiz Browser 0.94. From the inner ring to the outer ring: Percent AT, GC Skew, Global Inverted Repeats, Global Direct Repeats, Position Preference, Stacking Energy and Intrinsic Curvature.</p

Composite dendrogram for the three strains of <i>V</i>. <i>mimicus</i> isolated from frozen shrimp process (<i>V</i>. <i>mimicus</i> 87, 92 and 93) and <i>V</i>. <i>mimicus</i> CAIM 602T (type strain).

<p>The dendrogram and a similarity matrix were obtained by a cluster analysis of ERIC-PCR, GTG-5, RAPD and ARDRA (Bionumerics, Applied Maths, Inc).</p

Dendrograms of ERIC-PCR, RAPD, GTG-5PCR and ARDRA used for the analysis of <i>V</i>. <i>mimicus</i> 87, 92, 93 and CAIM 602 (type strain).

<p>The images were analyzed with Bionumerics software (Applied Maths, Inc.) with Dice correlation coefficient for the distance matrix and UPGMA with optimization set at 1% to create the dendrogram.</p