Virulence associated factors and antibiotic sensitivity pattern of Escherichia coli isolated from cattle and soil

Abstract

Aim: The present study was conducted to isolate pathogenic Escherichia coli from the faeces of apparently healthy cattle and soil of the farms to determine their susceptibility to commonly used antibiotics. Materials and Methods: A total of 90 samples (70 faecal and 20 soil samples) were collected aseptically and processed under required conditions for the isolation of E. coli. To confirm the isolates as E. coli, various biochemical tests like IMViC were performed. To assess the virulence of isolates, they were subjected to Congo red dye assay and hemolysis assay. Antibiotic sensitivity pattern of pathogenic isolates was studied by Disc diffusion method. Results: The prevalence of E. coli was observed to be 85.71% and 20% from the faecal and soil samples, respectively. Based on the phenotypic characteristics on CT SMAC and MUG Sorbitol, none of the isolates were found to be E. coli O157. The percent positivity on Congo red dye assay was 44.28% for faeces and 5% for soil while only faecal E. coli (4.28%) were found to be positive for hemolysis assay. The antibiogram of all 35 pathogenic isolates against 8 antibiotics showed that majority of pathogenic strains exhibited high level of sensitivity to Ceftriaxone (95%), Ciprofloxacin (93%), Amikacin (90%), Gentamycin (89%) and low level of sensitivity against Ampicillin (8%) and Streptomycin (5%). All isolates were 100% resistant to Amoxicillin and Tetracycline. Conclusion: Cattle act as main reservoirs of pathogenic E. coli that may enter the food chain by faecal contamination and pose potential public health hazards.

Keywords

• alpha hemolysis
• antibiogram
• congo red dye assay
• E. coli
• virulence factor