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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

Plasmid pP4 of strain P4.Alignment of predicted sequence of conjugative plasmid pP4 of strain P4 aligned to plasmid F of strain K-12 and to plasmid p1303_109 of mastitis strain 1303.
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pone.0136387.g004: Plasmid pP4 of strain P4.Alignment of predicted sequence of conjugative plasmid pP4 of strain P4 aligned to plasmid F of strain K-12 and to plasmid p1303_109 of mastitis strain 1303.

Mentions: Strain specific features were found in each of the three MPEC strains studied (50, 91, 130 functions in strain VL2874, VL2732 and P4, respectively). Strain P4 specific features were mainly associated with prophages and with phospholipid and fatty acid biosynthesis. As previously reported [27], strain P4 also harbors a conjugative plasmid type IncF IC(FII), here named pP4, comprising contigs 25, 40, 42 and 59 of the current assembly. The presence of this plasmid in the genome of strain P4 was confirmed here by gel electrophoresis (data not shown). In silico analysis showed that the pP4 plasmid is estimated to be about 112 Kb long, to have a 47.7 GC percentage and to include 118 CDS. Plasmid pP4 is nearly identical to the plasmid F of strain K-12 (AP001918). Although virulence factors were not detected on the pP4 plasmid, an interesting observation was the presence of a region of 14,639 bp beyond the K-12 plasmid F backbone. BLAST search of this region revealed that it is 99% identical to plasmid p1303_109 (CP009167), found in the mammary pathogenic E. coli strain 1303 that was also isolated from acute bovine mastitis [54] (Fig 4). This region has 45.7 GC percent and includes 16 CDS (11 mobile element proteins, 3 hypothetical proteins and co-activators of prophage gene expression IbrA and IbrB).


Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli.

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

Plasmid pP4 of strain P4.Alignment of predicted sequence of conjugative plasmid pP4 of strain P4 aligned to plasmid F of strain K-12 and to plasmid p1303_109 of mastitis strain 1303.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0136387.g004: Plasmid pP4 of strain P4.Alignment of predicted sequence of conjugative plasmid pP4 of strain P4 aligned to plasmid F of strain K-12 and to plasmid p1303_109 of mastitis strain 1303.
Mentions: Strain specific features were found in each of the three MPEC strains studied (50, 91, 130 functions in strain VL2874, VL2732 and P4, respectively). Strain P4 specific features were mainly associated with prophages and with phospholipid and fatty acid biosynthesis. As previously reported [27], strain P4 also harbors a conjugative plasmid type IncF IC(FII), here named pP4, comprising contigs 25, 40, 42 and 59 of the current assembly. The presence of this plasmid in the genome of strain P4 was confirmed here by gel electrophoresis (data not shown). In silico analysis showed that the pP4 plasmid is estimated to be about 112 Kb long, to have a 47.7 GC percentage and to include 118 CDS. Plasmid pP4 is nearly identical to the plasmid F of strain K-12 (AP001918). Although virulence factors were not detected on the pP4 plasmid, an interesting observation was the presence of a region of 14,639 bp beyond the K-12 plasmid F backbone. BLAST search of this region revealed that it is 99% identical to plasmid p1303_109 (CP009167), found in the mammary pathogenic E. coli strain 1303 that was also isolated from acute bovine mastitis [54] (Fig 4). This region has 45.7 GC percent and includes 16 CDS (11 mobile element proteins, 3 hypothetical proteins and co-activators of prophage gene expression IbrA and IbrB).

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