Molecular detection of nine essential virulence genes in Vibrio cholerae from recent cholera outbreaks in Ethiopian

Objective: Cholera is an acute diarrheal disease caused by Vibrio cholerae O1 or O139 serogroups. Vibrio cholerae O1 and O139 serogroup have different virulence and toxin associated genes. The mPCR method is used for detecting virulence and toxin associated (VTA) genes. The aim of the current study was to detect virulence genes in Vibrio cholerae using mPCR from recent cholera outbreak sites in Ethiopia. Methods: A total of 125 Vibrio cholerae isolates were obtained from 415 cholera-suspected participants using blood agar and thiosulfate citrate bile salt sucrose agar during the 2022–2024 outbreak in Ethiopia. A single colony was subcultured into nutrient agar. From NA, 3 to 5 colonies were taken for DNA extraction using the QIAamp® DNA Extraction Kit. The extracted DNA was amplified using mPCR. The mPCR products were visualized using 1.5% agarose gel electrophoresis in 1x TAE buffer and visualized under UV illumination following ethidium bromide staining. Results: All identified Vibrio cholerae isolates were O1 serogroups, El Tor biotypes, and Inaba serotypes. The frequently detected virulence genes were hlyA, followed by ompW, rfbO1, tcpA, zot, ompU, toxR, ace, and rtxC. All of these virulence genes were detected in Oromia, Amhara, and Addis Ababa. However, the detection frequencies were different across the regions. Conclusion: A high prevalence of virulence genes was identified in Ethiopia. The result of this study shows that cholera-causing V. cholerae strains are evolving constantly in epidemic areas in the country. This highlights the potential of the occurrence of more virulent V. cholerae strains.