Characterization of Escherichia coli isolated from foals.

This research article discusses the testing and analysis of 99 strains of E. coli found in foals (baby horses), with the aim of distinguishing the strains associated with diarrheic and healthy foals. The findings revealed the presence of potentially dangerous strains even in the foals that appeared healthy.

Research Methodology

• The researchers collected 99 strains of E.coli from foals for this study.
• These strains were extensively analyzed and characterized based on various parameters such as serotype, biotype, antibiogram, hemolysin production, fimbrial hemagglutinins, certain toxin genes and the existence of the attaching effacing (eae) gene.
• Both, foals showing symptoms of diarrhea and healthy foals, were considered for this study.

Key Findings

• The study found no distinguished characteristics or differences based on serotype, biotype, or antibiogram between E. coli strains isolated from diarrheic foals and those from normal foals.
• However, differences were observed in terms of hemolysin production (a type of toxin) and the presence of mannose-resistant hemagglutinins (a form of protein) between E. coli from both groups of foals.
• Three strains isolated from diarrheic foals were found to be positive for slt (Shiga like toxin) genes, and one was positive for STb (Heat-stable enterotoxin B) and LT (heat-labile enterotoxin) genes. One strain from a healthy foal also had the STb gene.
• As determined by the polymerase chain reaction, a technique to amplify the number of copies of a specific region of DNA, eight strains of E. coli possessed the eae (intimin) gene, which is typically found in pathogenic E.coli strains. Among these, seven strains were from diarrheic foals, and one was from a healthy foal.
• The eae-positive strains did not possess slt genes and vice versa, suggesting different virulence factors at play in these two types of strains.

Implications

• The results of this study indicate that strains of E. coli, which produce enterotoxins, are not significantly involved in causing sporadic diarrhea in foals.
• However, the presence of slt-positive and eae-positive strains in the feces of both diarrheic and healthy foals could suggest the potential for pathogenic manifestations if conditions change.