Detecção de genes de virulência e grupos filogenéticos de amostrasEscherichia coli isoladas de cães no Brasil
INTRODUCTIONEscherichia coli are a component of normal intestinal microbiota in humans and other animals. Phenotypic and genotypic characteristics allow the identification of E. coli pathogenic strains or pathovars (COURA et al., 2014). Dogs are colonized by E. coli during the first days of their life and some strains can cause enteric or extra-intestinal infections (BEUTIN, 1999 (BEUTIN, 1999). Other pathovars are associated with diarrhea in other animals, namely enteroaggregative E. coli (EAEC) and enteroinvasive E. coli (EIEC) (MAINIL, 2013). Because of the close contact with humans, dogs could increase the risk of transmitting potentially zoonotic microorganisms, such as EPEC and STEC (BEUTIN, 1999).In addition to the pathotype and pathovar classification, E. coli strains can be assigned to one of the seven phylogenetic groups, including A, B1, B2, C, D, E, and F (CLERMONT et al., 2013). E. coli genomic structure has shown that the strains belonging to different phylogroups are associated with the disease state and source of isolation (CLERMONT et al., 2013). The extraintestinal pathogenic E. coli (ExPEC) strains are clustered mostly in groups B2 and D and intestinal pathogenic E. coli are mostly in phylogroups A, B1, and E (ESCOBAR- PÁRAMO et al., 2004; CLERMONT et al., 2011). Although phylogenetic characterization is an important tool to improve the understanding of E. coli populations and the relationship between strains and disease (CLERMONT et al., 2011;COURA et al., 2015), few studies have determined phylogenetic groups of E. coli isolated from dogs worldwide, and of those that did, the most frequently used method was a triplex PCR method developed by CLERMONT in 2000. This method is only capable of determining phylogroups A, B1, B2, and D (HARADA et al., 2012;SALVARANI et al., 2012;SCHMIDT et al., 2015) instead of the seven phylogroups that were detected in this study. In Brazil, only two studies identified E. coli pathovars associated with diarrhea in dogs (ALMEIDA et al., 2012;PUÑO-SARMIENTO et al., 2013), but none determined the phylogenetic groups of E. coli. Therefore, this study aimed to detect the virulence genes, pathovars, and phylogenetic groups of E. coli strains isolated from the feces of dogs with and without diarrhea.
MATERIALS AND METHODS
Stool samplesStool samples were collected from 154 dogs, of which 92 were diarrheic and 62 were without diarrhea. Samples from diarrheic dogs were obtained directly from the rectum, at the Veterinary Hospital of Universidade Federal de Minas Gerais (Belo Horizonte city), upon admission. Collections were performed from dogs that were undergoing a consultation for the occurrence of diarrhea. With owner's consent, fecal samples from non-diarrheic animals were obtained from the dogs of students attending the Universidade Federal de Minas Gerais. For non-diarrheic dogs, fecal samples were either taken directly from the rectum or after spontaneous ...