Prevalence of Biofilm Formation and Wide Distribution of Virulence Associated Genes among Vibrio spp. Strains Isolated from the Monastir Lagoon, Tunisia

Abstract

A b s t r a c tIn the current study, 65 Vibrio spp. were isolated from the Monastir lagoon water, were characterized phenotypically and genotypically. In addition, we looked for the presence of three Vibrio parahaemolyticus virulence genes (tlh, trh and tdh) and ten Vibrio cholerae virulence genes (ctxA, vpi, zot, ace, toxR, toxT, tosS, toxRS, tcpA and cpP). We also investigated the antibiotic susceptibilities and the adherence ability of the identified strains to abiotic material and to biotic surfaces. The cytotoxicity activity against HeLa and Vero cell lines were also carried out for all tested strains. All Vibrio isolates were identified to the species level and produced several hydrolytic exoenzymes. The results also revealed that all strains were expressing high rates of resistance to tested antibiotics. The minimum inhibitory concentration (MIC) values showed that tetracycline and chloramphenicol were the most effective antibiotics against the tested bacteria. Vibrio alginolyticus and V. cholerae species were the most adhesive strains to both biotic and abiotic surfaces. Besides, V. alginolyticus isolates has the high levels of recombination of genes encoding V. cholerae and V. parahaemolyticus virulence factors. In vitro cytotoxic activities of several Vibrio extracellular product were also observed among HeLa and Vero cells. 308for investigation of the presence of three V. parahaemolyticus virulence genes (tlh, trh and tdh) and ten V. chole rae virulence genes (ctxA, vpi, zot, ace, toxR, toxT, tosS, toxRS, tcpA and tcpP). The isolates were also tested for their cytotoxic activity towards two epithelial cells. Their pattern of resistance to antibiotics was also carried out.

Rapid and Visualized Detection of Virulence-Related Genes of Vibrio cholerae in Water and Aquatic Products by Loop-Mediated Isothermal Amplification

“…This approximately 7-kb pathogenic island carries ctxAB, zot, ace, cep, and orfU genes (5). It has been reported that the zot gene encodes a zonula occludens toxin that increases transcellular ion transport and contributes to diarrhea in cholera, whereas the ace gene encodes an accessory cholera enterotoxin that disturbs small-intestinal tight junction permeability (11,18,20). In addition, previous studies have indicated that a cri gene is an important virulence-related gene required for toxin-linked cryptic plasmid replication in V. cholerae (26), whereas a nanH gene encodes a neuraminidase that is a key factor in the infectious process of many viruses and pathogenic bacteria (9).…”

“…In this study, based on the previous research, the LAMP method was applied for the first time in detection of four important virulence-related genes-ace, zot, cri, and nanH-of V. cholerae. The former two genes contribute to diarrhea in pandemic cholera (11,18,20), whereas the cri and nanH genes are key factors required for toxins (26) and the infectious process of many viruses and pathogenic bacteria (9), respectively. Inner, outer, and loop probes were designed and synthesized to target each of these genes.…”