Frequency of Escherichia coli virotypes in calf diarrhea and intestinal morphologic changes associated with these virotypes or other diarrheagenic pathogens

Abstract

Calf diarrhea is a common cause of pre-weaning morbidity and mortality in cattle operations. We evaluated the role of Escherichia coli by assessing the frequency of genes encoding virulence factors (virotypes) in E. coli from feces or intestinal contents, and the association of these virotypes or other diarrheagenic pathogens with intestinal morphologic changes in calves with or without diarrhea. E. coli was isolated from 408 feces and 105 intestines of calves with diarrhea and compared to those isolated from 635 feces and 100 intestines of calves without diarrhea, from 2002 to 2016. Virotype EAST1:F17, in combination with minor virotypes, was the most commonly detected type, but without differences in frequency between the 2 groups of calves. No significant intestinal morphologic changes were observed with the different E. coli virotypes in either group of calves, except for bacterial attachment to enterocytes for virotype STa:F5, which was detected only in calves with diarrhea. These observations suggest that E. coli, excluding virotype STa:F5, is not a significant diarrhea-causing agent in calves. However, the intestinal lesions observed in ~82% of calves with diarrhea were attributed to other diarrheagenic pathogens that include bovine coronavirus, Clostridium perfringens, Cryptosporidium spp., Eimeria spp., rotavirus, and Salmonella spp.

Cryptosporidium parvum and other enteric pathogens in scouring neonatal dairy calves from the Al Ain region, United Arab Emirates

“…In the present case report, E. coli was isolated from all the 36 faecal samples while the E. coli K99 antigen was only detected in 13 specimens. While E. coli K99 is an important cause of neonatal calf scours, other virulence factors including but not limited to F41, intimin, STa , Stx1 , Stx2 have also been reported in E. coli isolates from scouring neonatal calves ( Barigye et al, 2012 ; Ngeleka et al, 2019 ). While majority of the E. coli isolates from a bovine calf intestine are certainly normal flora, some of the K99-negative isolates cultured during the present study could have well been carrying other non-K99 virulence factors.…”

Antimicrobial Resistance, Serologic and Molecular Characterization of E. coli Isolated from Calves with Severe or Fatal Enteritis in Bavaria, Germany

“…Other published results suggested a positive correlation between animal age and the amount of Shiga toxin, supporting our findings including animals of young age [ 69 , 70 , 71 ]. Targeted infection studies with STEC led to severe disease and bloody diarrhea in neonatal calves, but more recent studies disproved this observation revealing a still controversial discussion [ 4 , 72 , 73 , 74 ].…”

Serotypes, Virulence Factors and Antibiograms of Escherichia coli Isolated from Diarrhetic Calves in Egypt: A review

“…These factors was called cytotoxic necrotizing factor (CNF). It has a molecular mass of approximately 115 Kda, the pathogenic countenance of E. coli O157: H7 involve the producing of Shiga toxin 1 (Stx1) and/or Shiga toxin 2 (Stx2), the possession of a locus of enterocyte effacement containing an eae A gene that encodes a protein called intimin, and the possession of an ~ 60 -Mda plasmid that encodes a hemolysin (Ngeleka, et al, 2019).…”