Virulence factors of Escherichia coli isolated from calves with diarrhea in Brazil

Abstract

Two hundred and five Escherichia coli strains isolated from calves with diarrhea from mid-western Brazil were screened for the presence of virulence factors associated with bovine colibacillosis. One hundred and two (49.8%) of the E. coli strains produced toxins: Shiga toxins 1 (9.7%) and 2 (6.3%), α-hemolysin (9.7%), enterohemolysin (6.8%), Cytotoxic Necrotizing Factors type 1 (0.5%), and type 2 (4.4%), enterotoxins LT-II (8.3%) and STa (3.9%). No strain produced enterotoxin LT-I. Fimbrial adhesins F5 and F17 were produced by 7.3% and 4.8% of the strains, respectivly, and none expressed F41. Seven strains (3.4%) possessed the gene eae and belonged to serotypes O26:H-; O111:H-and O118:H16. These results suggest that calves in Brazil may be an important source of pathogenic E. coli for animals and humans.

Virulence factors of Escherichia coli isolated from diarrheic calves

“…Colibacillosis is common in Brazil, as some studies have reported (Leomil et al, 2003;Salvadori et al, 2003). Among the 173 E. coli isolates studied from northwestern of São Paulo State, 85 (49.1%) were found to be positive for at least one of the virulence factors examined, a result similar to that reported by Salvadori et al (2003).…”

Detection of virulence and antimicrobial resistance genes in Escherichia coli isolates from diarrhoiec dogs in Iran

“…In this study, the prevalence (50%) of EHEC pathotype is higher compared against 1 (7.1%) of the isolates which haboured cnf (1) only and was regarded as NTEC (De Rycke et al 1999;Landraud et al 2000, Salvadoris et al 2003, Shahrani et al 2014, and 6 (42.9%) which haboured stx only and were grouped as STEC (Aslani et al 2008, Shahrani et al 2014. This result suggested that EHEC strains may be the predominant diarrhoeagenic E. coli pathotype isolated from dogs with diarrhoea in Iran.…”

“…Diarrhoeagenic E. coli isolate may belong to the enteroinvasive E. coli (EIEC), enterohaemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), entroaggregative E. coli (EAEC), necrotoxic E. coli (NTEC), enterotoxigenic/shiga-like toxin producing E. coli (STEC) or diffusely adherent E. coli (DAEC) strain/ pathotypes, depending on the type of virulent factor(s) elaborated and the type of lesion produced (Bien et al 2011, De Rycke et al 1999, Puno-Sarmiento et al 2013, Salvadoris et al 2003. Nevertheless, canine diarrhoea may not primarily be caused by E. coli, although pathogenic strains of E. coli has been widely incriminated in cases of diarrhoea in humans and animals (Aslani et al 2008, Salvadoris et al 2003, Shahrani et al 2014. In many clinical conditions of dogs such as canine distemper, parvoviral enteritis, coronavirus infection, helminthosis, etc and a myriad of non-infectious and toxic conditions, the integrity of intestinal mucosa is altered resulting in enteritis and diarrhoea (Hammermueler et al 1995, Torkan et al 2015.…”

“…Diarrhoeagenic E. coli strains have been reported to harbour genes which encode virulent factors responsible for their pathogenicity (Aslani et al 2008, Bien et al 2011, Shahrani et al 2014. Virulent factors often possessed by pathogenic E. coli strains and used for their classification into pathotypes include: Shiga-like/Shiga toxin (stx) encoded by Shiga toxinogenic (stx) genes 1 and 2 (stx1 and stx2), cytotoxic necrotizing factor (cnf) encoded by cytotoxic necrotizing factor genes 1 and 2 (cnf1 and cnf2), and intimin encoded by E. coli attaching and effacing (eae) gene (De Rycke et al 1999, Landraud et al 2000, Salvadoris et al 2003, Bentancor et al 2007, Puno-Sarmiento et al 2013. These virulent factors have been widely reported to be associated with diarrhoea in humans and animals (Randall et al 2004, Aslani et al 2008, Kavitha et al 2010.…”

“…Various antimicrobial resistance determinants including multidrug resistance genes encoding for extended-spectrum β-lactamases have been described in E. coli isolates from companion animals (Bradford 2001, Costa et al 2008, Ewers et al 2010, Shaheen et al 2011, Tajbakhsh et al 2015. Antimicrobial resistance genes spread easily among bacterial organisms by mobile genetic elements like plasmids, and transposons (Salvadoris et al 2003, Randall et al 2004.…”