Occurrence of pathogenic vibrios in coastal areas of France

Abstract

Aims: This study was carried out to investigate the occurrence of potentially pathogenic species of Vibrio in French marine and estuarine environments. Methods and Results: Samples of coastal waters and mussels collected between July and September 1999 were analysed by culture, using selective media including thiosulphate-citratebile salts-sucrose and modified cellobiose-polymixin B-colistin agar. Presumptive Vibrio colonies were isolated and identified using selected biochemical tests. Specific primers based on flanking sequences of the cytolysin, vvhA gene, pR72H DNA fragment and 16S-23S rRNA intergenic spacer region (ISR) were used in a polymerase chain reaction (PCR) to confirm the identification of Vibrio vulnificus, V. parahaemolyticus and V. cholerae, respectively. In this study, V. alginolyticus (99 of 189) was the predominant species, followed by V. parahaemolyticus (41 of 189), V. vulnificus (20 of 189) and non-O1/non-O139 V. cholerae (three of 189). All 20 V. vulnificus isolates showed PCR amplification of the vvhA gene, 16 of which had been isolated from estuarine water. The PCR amplification of the pR72H DNA fragment in 41 V. parahaemolyticus isolates generated two unique amplicons of 387 and 320 bp. The latter, present in 24AE4% of these isolates, had not previously been found in V. parahaemolyticus strains examined to date. Amplification of the trh gene in two of the isolates suggested these to be virulent strains. Three strains identified as V. cholerae by amplification of the 16S-23S rRNA ISR were confirmed to be non-cholera (non-O1/non-O139) strains. Conclusions:The results of this study demonstrated the presence of pathogenic Vibrio species in French coastal waters. Furthermore, the PCR approach proved useful for the rapid and reliable confirmation of species identification. Significance and Impact of the Study: These findings indicate the potential sanitary risk associated with the presence of pathogenic Vibrio spp. in cultivated mussels and in the aquatic environment. The PCR can be used to detect pathogenic vibrios directly in environmental samples.

Temporal and Spatial Distribution Patterns of Potentially Pathogenic Vibrio spp. at Recreational Beaches of the German North Sea

“…This suggests that the ratio observed here is realistic, although more strains need to be checked for more reliable evidence. Presence of the trh gene alone seems to be a common characteristic of V. parahaemolyticus communities in Northern European waters and has been shown for several studies in this region [39,69,70]. Up to now, only tdh-positive strains were associated with V. parahaemolyticus infections in Europe, however [68], and tdh is the gene that has been mainly attributed to haemolysis [71].…”

“…The potential health risk by this organism needs to be properly determined, especially during the summertime. The haemolysis gene vvh has been associated with a large proportion of V. vulnificus isolates in Northern European Waters [37,39] and was even used as a species-specific marker [74], suggesting that environmental V. vulnificus isolates inherently carry haemolysis genes. Despite this, V. vulnificus is generally not very virulent; however, it has an exceptional toxicity with 30 % of wound infections ending in fatalities [4].…”

“…[15]), few environmental studies have considered the sedimentary matrix (e.g. [39,40]), thus neglecting an important component with regard to the assessment of possible health risks.…”

Isolation and characterization of Vibrio parahaemolyticus from seafoods along the southwest coast of India

“…In the 1980s few gastroenteritis cases were reported from the KP negative V. parahaemolyticus isolates, which led to the discovery of the thermostabele direct haemolysin (TDH)-related haemolysin, TRH (Hervio-Heath et al 2002). Studies revealed the TDH and TRH, encoded by the phenotypic tests viz., KP and urea hydrolysis respectively, were considered as phenotypic markers for pathogenicity (Kaysner et al 1994).…”

Occurrence and distribution of virulent strains of Vibrio parahaemolyticus in seafoods marketed from Cochin (India)

“…Epidemiological studies revealed an association between the Kanagawa positive phenomenon (KP+) and gastroenteritis (Okuda et al 1997a). In the 1980s few gastroenteritis cases were reported from the KP negative V. parahaemolyticus isolates, which led to the discovery of the TDH-related haemolysin (TRH) (Hervio-Heath et al 2002). Studies revealed the thermostable direct haemolysin (TDH) and the TDH-related haemolysin (TRH), encoded by the tdh and trh genes, respectively, as the major virulence factors of this organism (Shirai et al 1990).…”