The ecology of Escherichia coli - Escherichia coli: Pathotypes and Principles of Pathogenesis - page 5

FIGURE 1.2 Relative abundance of the main E. coli phylo-groups (A, B1, B2, D) with respect
to the source of isolation. Unpublished data and data taken from Gordon and Cowling (2003) , and
Power et al. (2005) .
FIGURE 1.3 Relative abundance of the main E. coli phylo-groups (A, B1, B2, D) with respect
to the source of isolation. Data taken from Unno et al. (2009) , Tenaillon et al. (2010) , and Li et al.
(2010) .
explain the very different relative abundances of the phylo-groups recovered
from humans living in different parts of the world.
Therefore, strains belonging to the different phylo-groups appear to have
different ecological niches and life-history characteristics. Phylo-group A and
B1 strains appear to be generalists able to occupy a broad range of vertebrate
hosts. By contrast, B2 and D strains are more commonly isolated from birds and
mammals than ectotherms. It has been argued that phylo-group B2 strains are