Phylogenetic grouping and probiotics antibacterial studies on Escherichia coli isolates obtained from calves' excrement in an Industrial slaughterhouse of Mashhad city

Salari, Zahra; Moghbeli, Majid; Farzin, Hamidreza; Jamshidian Mojaver, Majid

doi:10.22092/ari.2025.368000.3462

Phylogenetic grouping and probiotics antibacterial studies on Escherichia coli isolates obtained from calves' excrement in an Industrial slaughterhouse of Mashhad city

Articles in Press

Document Type : Original Articles

Authors

¹ Department of Microbiology, Damghan branch, Islamic Azad University, Damghan, Iran.

² Mashhad Branch, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran

10.22092/ari.2025.368000.3462

Abstract

Background: Diarrhea in calves caused by Escherichia Coli (E. Coli) poses an economic risk to livestock farms. Classifying new pathogen strains through genetic recombination aids in infection prevention and treatment. This study aims to identify E. Coli strains in calf feces and examine the antibacterial effects of probiotics on them.
Methods: 85 samples were prepared from healthy and diarrheal calves' excrement at Mashhad industrial slaughterhouse to isolate E. Coli strains. Then, they were phylogenetically grouped using multiplex polymerase chain reaction (PCR) on yjaA, chuA, arpA, and TspE4.C2 genes, based on the new Claremont method, and were classified using the ERIC-PCR method based on genetic diversity. Also, double-layer culture and plate-well methods investigated Lactobacilli's antibacterial and anti-adhesion effects (L.) Casei and Plantarum and their aggregation effects with isolates were done using the Coaggregation method.
Results: Based on the PCR results of 70 E. Coli strains, the phylogenetic grouping was classified as A( 40%), B1 (17.14%), B2 (14.3%), E (7.14%), F (5.71%), D (4.29%), C (0%), and unknown (11.42%). Their genetic diversity consisted 3 main clusters including subclusters: G1 (2 isolates), G2 (4 isolates), G3 (6 isolates), G4 (3 isolates), G5 (18 isolates), G6 (3 isolates). Probiotics' antibacterial and anti-adhesion effects were confirmed against pathogenic and non-pathogenic E. Coli strains, and these effects were more impressive about L. Casei than L. Plantarum.
Conclusion: To effectively prevent diarrhea in calves, it is essential to understand the phylogenetic grouping and genetic diversity of the bacterial causes. Additionally, probiotics can expedite the treatment of diarrhea.

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