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Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli.

Blum SE, Heller ED, Sela S, Elad D, Edery N, Leitner G - PLoS ONE (2015)

Bottom Line: Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes.Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism.Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel; National Mastitis Reference Center, Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel; Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel.

ABSTRACT
Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study reveals virulence factors and phenotypic characteristics of MPEC that may play a role in pathogenesis of E. coli mastitis.

No MeSH data available.


Related in: MedlinePlus

Relative Manhattan distance of predicted proteomes.Predicted proteomes of three mammary pathogenic E. coli and representatives of diverse E. coli pathotypes and non-pathogenic strains. Dendrogram generated on the basis of gene presence/absence considering all genes, including singletons, and validated after 100 bootstraps repetitions (depicted in red). Genes were clustered by 80% sequence identity over 80% sequence length. The three mammary pathogenic strains are closely related, and significantly distant from the environmental, non-mammary pathogenic strain K71.
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pone.0136387.g008: Relative Manhattan distance of predicted proteomes.Predicted proteomes of three mammary pathogenic E. coli and representatives of diverse E. coli pathotypes and non-pathogenic strains. Dendrogram generated on the basis of gene presence/absence considering all genes, including singletons, and validated after 100 bootstraps repetitions (depicted in red). Genes were clustered by 80% sequence identity over 80% sequence length. The three mammary pathogenic strains are closely related, and significantly distant from the environmental, non-mammary pathogenic strain K71.

Mentions: Proteomes were predicted for representative genomes and compared pairwise for gene clustering into families. The Manhattan distance between the predicted proteomes based on gene family presence/absence is shown as a dendrogram in Fig 8. Overall, ExPEC, mainly UPEC genomes, clustered separately from most of the intestinal pathotypes. MPEC strains were included in the general intestinal E. coli cluster, and were separated from the non-mammary pathogenic strain K71. Similarity of mastitis strains and other E. coli proteomes ranged from 56% to 79%. A full similarity matrix of pairwise comparisons between proteomes is provided in S1 Fig. The similarity between MPEC strains and the non-mammary pathogenic strain K71 was 71.7%, 69.7% and 72.6% for strain VL2874, VL2732 and P4, respectively. In contrast, the similarity among mastitis strains was 80.5% between VL2874 and VL2732, 80.5% between VL2732 and P4, and 79.7% between VL2874 and P4.


Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli.

Blum SE, Heller ED, Sela S, Elad D, Edery N, Leitner G - PLoS ONE (2015)

Relative Manhattan distance of predicted proteomes.Predicted proteomes of three mammary pathogenic E. coli and representatives of diverse E. coli pathotypes and non-pathogenic strains. Dendrogram generated on the basis of gene presence/absence considering all genes, including singletons, and validated after 100 bootstraps repetitions (depicted in red). Genes were clustered by 80% sequence identity over 80% sequence length. The three mammary pathogenic strains are closely related, and significantly distant from the environmental, non-mammary pathogenic strain K71.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4556653&req=5

pone.0136387.g008: Relative Manhattan distance of predicted proteomes.Predicted proteomes of three mammary pathogenic E. coli and representatives of diverse E. coli pathotypes and non-pathogenic strains. Dendrogram generated on the basis of gene presence/absence considering all genes, including singletons, and validated after 100 bootstraps repetitions (depicted in red). Genes were clustered by 80% sequence identity over 80% sequence length. The three mammary pathogenic strains are closely related, and significantly distant from the environmental, non-mammary pathogenic strain K71.
Mentions: Proteomes were predicted for representative genomes and compared pairwise for gene clustering into families. The Manhattan distance between the predicted proteomes based on gene family presence/absence is shown as a dendrogram in Fig 8. Overall, ExPEC, mainly UPEC genomes, clustered separately from most of the intestinal pathotypes. MPEC strains were included in the general intestinal E. coli cluster, and were separated from the non-mammary pathogenic strain K71. Similarity of mastitis strains and other E. coli proteomes ranged from 56% to 79%. A full similarity matrix of pairwise comparisons between proteomes is provided in S1 Fig. The similarity between MPEC strains and the non-mammary pathogenic strain K71 was 71.7%, 69.7% and 72.6% for strain VL2874, VL2732 and P4, respectively. In contrast, the similarity among mastitis strains was 80.5% between VL2874 and VL2732, 80.5% between VL2732 and P4, and 79.7% between VL2874 and P4.

Bottom Line: Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes.Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism.Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel; National Mastitis Reference Center, Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel; Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan, Israel.

ABSTRACT
Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study reveals virulence factors and phenotypic characteristics of MPEC that may play a role in pathogenesis of E. coli mastitis.

No MeSH data available.


Related in: MedlinePlus