Detection of genes encoding ompW and ctxA of Vibrio cholerae isolated from shrimp and shellfish at Kedonganan fish market, Bali-Indonesia

Abstract

<p>Contamination of pathogenic bacteria in food can lead to the emergence of foodborne disease. One of foodborne disease which often occurs in some developing countries such as Africa, Southeast Asia, and Latin America is cholera which is caused by <em>Vibrio cholerae</em>. The disease is transmitted through beverages and food, especially contaminated seafood. <em>V. cholerae</em> has several virulence factors including the outer membrane protein W <em>(ompW)</em> and cholerae toxin <em>(ctx).</em>The<em> ompW</em> acts as a protective barrier and can also be used as a marker specific species of <em>V. cholerae</em> and cholerae toxin is an enterotoxin responsible for the incidence of diarrhea in a cholera outbreak produced by pathogenic <em>V. cholerae</em>. This study was an observational study to determine the level of contamination of <em>V. cholerae</em> by detecting the outer membrane protein W <em>(ompW)</em> and cholerae toxin subunit A <em>(ctxA)</em> gene of <em>V. cholerae</em> in shrimp and shellfish sold at Kedonganan fish market. Samples were taken using total sampling technique and obtained 24 samples consisting of 14 shrimp samples and 10 shellfish samples. Samples were examined using culture methods and biochemical tests, and then further tested using Duplex Polymerase Chain Reaction (dPCR) to detect <em>ompW</em> and <em>ctxA</em> gene. The dPCR assay results showed 8 out of 14 (57.1%) samples from shrimp and 1 out of 10 (10%) samples from the shellfish positive carried <em>ompW</em> gene, and found no positive samples carrying the <em>ctxA</em> gene in samples derived from shrimp and shellfish. Chi square test analysis results indicated contamination of <em>V. cholerae</em> in shrimp was higher than shellfish based on <em>ompW</em> gene (p<0.05). It can be concluded that the shrimp and shellfish at Kedonganan fish market are contaminated by <em>V. cholerae</em>. Further research is needed to detect the virulence factors besides <em>ompW</em> and <em>ctxA </em>of<em> V. cholerae</em> in seafood.</p><pre><strong> </strong></pre>Keywords: Foodborne disease, <em>Vibrio cholerae</em>, <em>ompW</em> gene<em>,</em> <em>ctxA</em> gene, and Duplex Polymerase Chain Reaction (dPCR).

Molecular Epidemiology of Antimicrobial Resistance and Virulence Profiles of Escherichia coli, Salmonella spp., and Vibrio spp. Isolated from Coastal Seawater for Aquaculture

“…For V. cholerae , more than half (51.3%) of the isolates were positive for ompW , which codes for an outer membrane protein, but none harbored the ctx gene which codes for the cholera toxin. This result agrees with previous studies showing that isolates of environmental V. cholerae are often not positive for the ompW gene [ 42 , 43 ]. The V. cholerae serogroups O1, O139, and O141 were also not found in this study.…”