Journal of Advances in Microbiology

Objective: Contamination of milk with Escherichia coli (E. coli) can pose significant public health and economic concerns. The current study was conducted to explore the prevalence and antibiotic resistance profiles of Shiga-toxin-producing Escherichia coli in milk samples of dairy cows in Egypt.

Study Design: Twenty milk samples were gathered from dairy cattle (ten from healthy cows and ten from mastitic cows) and examined for the presence of Shiga-toxin-producing E. coli using Eosin Methylene Blue agar. Molecular detection of virulence genes and phenotypic antimicrobial resistance were performed.

Results: E. coli was isolated from 65% (13/20) of the total milk samples (90% from mastitic cows and 40% from normal healthy cows). The virulence gene profiling of E.coli by polymerase chain reaction revealed that 84.62% (11/13) were Stx2a, 69.23% (9/13) were Stx2f, and 61.54% (8/13) were positive for Stx1 and Stx2 similarly. All the isolates showed resistance to Amikacin, Ciprofloxacin, Erythromycin, Linezolid, Penicillin G, and Trimethoprim/Sulfamethoxazole, while 92.3% expressed resistance to Amoxicillin/ Clavulanic acid, and Tylosin, and 84.62% of the isolates were resistant to Oxytetracycline indicating multidrug-resistant profiles.

Conclusion: The present work highlights the presence of various E. coli strains, including potential pathogens and multidrug-resistant isolates, in milk samples from dairy cows. Regular milk testing and improved mastitis control measures are the key to reduce the public health risks and to safeguarde dairy farm productivity.