Limits...
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

Heatmap of the area under the curve of phenotype microarray.Heatmap of the area under the curve (AUC) parameter extracted from kinetic data over 24 h in phenotype microarray with validation by 100 bootstrap repetitions. Numerals after the strain name indicate technical replicates of the same strain. The heatmap color indicates the AUC; yellow for higher values and blue for lower.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4556653&req=5

pone.0136387.g002: Heatmap of the area under the curve of phenotype microarray.Heatmap of the area under the curve (AUC) parameter extracted from kinetic data over 24 h in phenotype microarray with validation by 100 bootstrap repetitions. Numerals after the strain name indicate technical replicates of the same strain. The heatmap color indicates the AUC; yellow for higher values and blue for lower.

Mentions: The metabolic utilization of a total of 758 nutrient sources was assessed. Reactions were categorized into positive, weak or negative based on AUC values. All four strains were negative to a total of 243 reactions, weak to 31 reactions and positive to 127 reactions. A heatmap of AUC values for all reactions is presented in Fig 2, showing that strains P4 and VL2874 were similar, and strain VL2732 was the most divergent one. The number and percentage of positive reactions by nutrient type are presented in Table 3. Strain VL2732 was the most versatile in terms of the number of nutrients metabolized. Accordingly, the number of unique positive reactions in each strain, i.e. positive reactions in a single strain that were negative or weak in the other ones, was higher for strain VL2732 (n = 123, representing 36% of the positive reactions in this strain), in contrast to K71 (n = 7, 4% of positive reactions in this strain), VL2874 (n = 3, 2% of positive reactions in this strain) and P4 (n = 5, 3% of positive reactions in this strain). Notably, strain VL2732 showed the highest versatility in the ability to use peptides as a source of nitrogen, to metabolize organic sulfur compounds and in the responsiveness to nutritional supplements (measured as improved growth over non-supplemented medium). Whether these characteristics provide this strain with an advantage to explore the intra-cellular niche, thus allowing it to install a persistent infection in the mammary gland, could be a subject of further investigation.


Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli.

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

Heatmap of the area under the curve of phenotype microarray.Heatmap of the area under the curve (AUC) parameter extracted from kinetic data over 24 h in phenotype microarray with validation by 100 bootstrap repetitions. Numerals after the strain name indicate technical replicates of the same strain. The heatmap color indicates the AUC; yellow for higher values and blue for lower.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0136387.g002: Heatmap of the area under the curve of phenotype microarray.Heatmap of the area under the curve (AUC) parameter extracted from kinetic data over 24 h in phenotype microarray with validation by 100 bootstrap repetitions. Numerals after the strain name indicate technical replicates of the same strain. The heatmap color indicates the AUC; yellow for higher values and blue for lower.
Mentions: The metabolic utilization of a total of 758 nutrient sources was assessed. Reactions were categorized into positive, weak or negative based on AUC values. All four strains were negative to a total of 243 reactions, weak to 31 reactions and positive to 127 reactions. A heatmap of AUC values for all reactions is presented in Fig 2, showing that strains P4 and VL2874 were similar, and strain VL2732 was the most divergent one. The number and percentage of positive reactions by nutrient type are presented in Table 3. Strain VL2732 was the most versatile in terms of the number of nutrients metabolized. Accordingly, the number of unique positive reactions in each strain, i.e. positive reactions in a single strain that were negative or weak in the other ones, was higher for strain VL2732 (n = 123, representing 36% of the positive reactions in this strain), in contrast to K71 (n = 7, 4% of positive reactions in this strain), VL2874 (n = 3, 2% of positive reactions in this strain) and P4 (n = 5, 3% of positive reactions in this strain). Notably, strain VL2732 showed the highest versatility in the ability to use peptides as a source of nitrogen, to metabolize organic sulfur compounds and in the responsiveness to nutritional supplements (measured as improved growth over non-supplemented medium). Whether these characteristics provide this strain with an advantage to explore the intra-cellular niche, thus allowing it to install a persistent infection in the mammary gland, could be a subject of further investigation.

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