Improved isolation and detection of toxigenic from coastal water in Saudi Arabia using immunomagnetic enrichment.

BACKGROUND

is recognized globally as a cause of foodborne gastroenteritis and its widely disseminated in marine and coastal environment throughout the world. The main aim of this study was conducted to investigate the presence of toxigenic in costal water in the Eastern Province of Saudi Arabia by using immunomagnetic separation (IMS) in combination with chromogenic Vibrio agar medium and PCR targeting gene of species level and virulence genes.

METHODS

A total of 192 seawater samples were collected from five locations and enriched in alkaline peptone water (APW) broth. One-milliliter portion from enriched samples in APW were mixed with an immunomagnetic beads IMB) coated with specific antibodies against polyvalent K antisera and separated beads with captured bacteria streaked on thiosulfate citrate bile salts sucrose (TCBS) agar and CHROMagar Vibrio (CaV) medium.

RESULTS

Of the 192 examined seawater samples, 38 (19.8%) and 44 (22.9%) were positive for , producing green and mauve colonies on TCBS agar and CaV medium, respectively. Among 120 isolates of isolated in this study, 3 (2.5%) and 26 (21.7%) isolates of isolated without and with IMB treatment tested positive for the toxin regulatory (R) gene, respectively. Screening of the confirmed R gene-positive isolates revealed that 21 (17.5%) and 3 (2.5%) were positive for the thermostable direct hemolysin () encoding gene in strains isolated with IMB and without IMB treatment, respectively. None of the strains tested positive for the thermostable related hemolysin () gene. In this study, we found that the CaV medium has no advantage over TCBS agar if IMB concentration treatment is used during secondary enrichment steps of environmental samples. The enterobacterial repetitive intergenic consensus (ERIC)-PCR DNA fingerprinting analysis revealed high genomic diversity, and 18 strains of were grouped and identified into four identical ERIC clonal group patterns.

CONCLUSIONS

The presented study reports the first detection of producing in coastal water in the Eastern Province of Saudi Arabia.