Genome based phylogeny and comparative genomic analysis of intra-mammary pathogenic Escherichia coli.

Vincent P. Richards (1, 2) , Tristan Lefébure (2, 3) , Paulina Pavinski Bitar (2) , Belgin Dogan (4) , Kenneth Simpson (4) , Ynte H. Schukken (2) , Michael J Stanhope (2)

1 Department of Biological Sciences [Clemson]
2 Department of Population Medicine and Diagnostic Sciences
3 LEHNA - Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés
4 Department of Clinical Sciences, College of Veterinary Medicine

Escherichia coli is an important cause of bovine mastitis and can cause both severe inflam- mation with a short-term transient infection, as well as less severe, but more chronic inflam- mation and infection persistence. E. coli is a highly diverse organism that has been classified into a number of different pathotypes or pathovars, and mammary pathogenic E. coli (MPEC) has been proposed as a new such pathotype. The purpose of this study was to use genome sequence data derived from both transient and persistent MPEC isolates (two isolates of each phenotype) to construct a genome-based phylogeny that places MPEC in its phylogenetic context with other E. coli pathovars. A subsidiary goal was to con- duct comparative genomic analyses of these MPEC isolates with other E. coli pathovars to provide a preliminary perspective on loci that might be correlated with the MPEC phenotype. Both concatenated and consensus tree phylogenies did not support MPEC monophyly or the monophyly of either transient or persistent phenotypes. Three of the MPEC isolates (ECA-727, ECC-Z, and ECA-O157) originated from within the predominately commensal clade of E. coli, referred to as phylogroup A. The fourth MPEC isolate, of the persistent phe- notype (ECC-1470), was sister group to an isolate of ETEC, falling within the E. coli B1 clade. This suggests that the MPEC phenotype has arisen on numerous independent occa- sions and that this has often, although not invariably, occurred from commensal ancestry. Examination of the genes present in the MPEC strains relative to the commensal strains identified a consistent presence of the type VI secretion system (T6SS) in the MPEC strains, with only occasional representation in commensal strains, suggesting that T6SS may be associated with MPEC pathogenesis and/or as an inter-bacterial competitive attri- bute and therefore could represent a useful target to explore for the development of MPEC specific inhibitors.

Domaines: Biodiversité et Ecologie

Vincent P. Richards, Tristan Lefébure, Paulina Pavinski Bitar, Belgin Dogan, Kenneth Simpson, et al.. Genome based phylogeny and comparative genomic analysis of intra-mammary pathogenic Escherichia coli. . PLoS ONE, 2015, 10 (3, e0119799), pp.1-11. ⟨10.1371/journal.pone.0119799⟩. ⟨hal-01292456⟩