Some authors analyzed the distribution of the main phylogenetic groups among E. coli strains isolated from human and animal feces. Gordon and Selleck C646 Cowling [10] observed that the relative abundance of phylogenetic groups among mammals is dependent on the host diet, body mass and climate. Escobar-Páramo et al. [5] analyzing fecal strains isolated from birds, non-human mammals and humans, observed the prevalence of groups AZD4547 price D and B1 in birds,

A and B1 in non-human mammals, and A and B2 in humans. These authors concluded that one of the main forces that shapes the genetic structure of E. coli populations among the hosts is domestication. Baldy-Chudzik et al. [20] analyzed feces from zoo animals and found a prevalence of group B1 in herbivorous animals and a prevalence of group A in carnivorous and omnivorous animals. The aim of this work was to analyze the distribution of phylogenetic groups and subgroups in feces from different animals and to assess the potential application

of this analysis in identifying the major source of fecal contamination in the environment. Results In this work, 241 E. coli strains isolated from feces of different animals and 12 strains isolated from a sewage source were allocated into four phylogenetic groups (i.e. A, B1, B2 and D) and seven subgroups (i.e. A0, A1, B1, B22, B23, D1 and D2). As shown in Table 1, the strains analyzed were distributed among the seven subgroups, and the prevalence Urocanase indexes calculated for the subgroups were: A0 = 83.33%,

A1 = 83.33%, B1 CT99021 cell line = 100%, B22 = 50%, B23 = 16.67%, D1 = 66.67 and D2 = 66.67%. It is interesting to note that strains from group B1 were found among all the analyzed hosts, whereas strains from subgroup B23 were found only in humans. Table 1 Distribution of the E. coli phylogenetic subgroups among the hosts analyzed Phylogenetic subgroup Human Cow Chicken Pig Sheep Goat A0 0 12 7 4 4 1 A1 38 2 3 17 0 2 B1 8 29 2 9 20 13 B22 5 0 1 2 0 0 B23 7 0 0 0 0 0 D1 26 4 0 5 3 0 D2 10 3 0 2 2 0 Total 94 50 13 39 29 16 The graphic representation shown in Figure 1 allowed the identification of remarkable trends among the E. coli strains from the different hosts. Humans are the only host bearing strains from all the phylo-groups, except for subgroup A0. The strains found in the pig samples were also distributed among all phylo-groups, except for subgroup B23, which contains only strains from the human samples. Most of the strains from the chicken samples were included in subgroup A0, that is, these strains did not reveal the presence of the genetic markers investigated. Most of the strains of cows, goats and sheep fell within group B1, despite the fact that four strains of cows and three of chickens were assigned to subgroup D1 and two strains of goats and two of cows were assigned to group A1. Figure 1 Graphic representation of the occurrence of genetic markers in E. coli strains isolated from different hosts.