Virulence Profile of Enteropathogenic Escherichia Coli (Epec) Isolated From the Cases of Neonatal Calf Diarrhea

Abstract

H ealth of the newborn calves is a matter of balance concerning the pathogens, immune system of the newborn animal, environment and management system. Infection in newborn calves is multifactorial in nature and it seems to be the result of interaction between different factors that may contribute to the buildup of infection including the immunological, nutritional, and environmental factors, (Hosein, 2018). Neonatal calf diarrhea is one of the most serious health problems in the livestock industry and an important cause of economic losses due to high morbidity and mortality rates, high treatment costs and low growth rate, (Al-Alo et al., 2018; Anderson et al., 2003; Bazeley, 2003). Diarrhea is the most important cause of losses in calves up to 30 days of age and still problematic, likely because of the multi-factorial nature of the disease, Gomez and Weese (2017). Difference between health and disease among new born calves is very often just a slight tip of a delicate balance that weighs calf and environmental factors with the pathogens to which the calf will be exposed. E. coli an important enteric pathogen of bovine neonates, is established in intestines shortly after the birth and remains throughout life. It has been incriminated as a major cause of diarrhea characterized by progressive dehydration and death that may occur depending on the age of the calf when scour started and the pathotypes of E. coli involved (Nguyen et al., 2011). Several E. coli serotypes, causing morbidity and mortality, have been isolated from calves suffering from diarrhea (Wani et al., 2003). E. coli pathotypes that are incriminated in neonatal calf diar-research Article Abstract | A total of 14 (30.43%) diarrheic calves of 1-4 weeks out of 46 calves kept under poor hygienic conditions in a dairy farm were suffering clinically from acute diarrhea. Diarrheic calves showed fever, diarrhea, dehydration, pneumonia recumbence and death of two calves. Thirteen (92.85 %) isolates of E. coli out of the 14 collected rectal swaps of diarrheic calves were identified on bacteriological and molecular basis. The results of the amplification of phoAgene using PCR revealed that all E. coli isolates showed positive result for the presence of phoAgene, thus confirming their identity as E. coli. All tested E. coli isolates were positive for intimin (eae) A, attaching and effacing gene (gene species specific) for E. coli (100%). No isolate had shiga toxin1 (stx1), shiga toxin 2 (stx2), hemolysin (hylA), and E. coli enterotoxin genes heat stable enterotoxin (st) and heat labile enterotoxin (lt). The obtained results indicate the possible participation of pathogenic E. coli in calf diarrhea. EPEC represented 100% of the tested E. coli strains obtained from diarrheic calves. The obtained results indicated that EPEC infection is a major health problem among calves and suggests the significance of poor hygiene measures in the investigated farm the possible participation of calves in the zoonotic transmission of pathogenic E. coli.