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Updated: Aug 11, 2026
Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
Published on: December 23, 2022
Identification of Potential Vaccine Strains of Escherichia coli Isolates From Diarrhoeic Calves
Yasemin Erdoğan1, Ediz Kağan Özgen2, Murat Özmen1
1Department of Bacteriology, Erzurum Veterinary Control Institute, Republic of Türkiye Ministry of Agriculture and Forestry, Erzurum, Türkiye.
Background:
Escherichia coli is the most commonly isolated bacterium in cases of diarrhoea in calves under the age of 2 months.
Objectives:
This study aimed to identify E. coli strains with immunogenic potential by characterizing isolates from diarrheic calves through antigenic profiling and genotyping.
Methods:
The phenotypic and genotypic antibiotic resistance characteristics and virulence genes of the E. coli strains isolated from 500 faecal samples were examined, of which 88 were further genotyped using the Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA) method. Subsequently, 20 E. coli strains were selected based on their antibiotic resistance patterns and genetic typing (MLVA) results, and subjected to an analysis of their outer membrane vesicle profile.
Results:
Among these, strains Ec048 and Ec026 exhibited high OMV diversity and were identified as promising candidates for further immunogenic evaluation. Immunization of experimental animals with these strains enhanced humoural immune responses (IgG, IgM, CD20), whereas cellular immune parameters (CD4, CD8) showed no significant change.
Conclusions:
In conclusion, the study demonstrates that strains Ec048 and Ec026 elicit strong humoural immune responses, indicating their potential for vaccine development. However, protective efficacy was not assessed, and further studies including challenge experiments are required to confirm their suitability as vaccine strains.
