Occurrence of the tdh and trh genes in Vibrio parahaemolyticus isolates from waters and raw shellfish collected in two French coastal areas and from seafood imported into France.

Unité du Choléra et des Vibrions, Centre National de Référence des Vibrions et du Choléra, Institut Pasteur, 25, rue du Dr Roux, 75 724 Paris 15, France.
International Journal of Food Microbiology (Impact Factor: 3.43). 04/2004; 91(3):319-25. DOI: 10.1016/j.ijfoodmicro.2003.07.006
Source: PubMed

ABSTRACT The occurrence of the hemolysin genes, tdh and trh, in Vibrio parahaemolyticus strains isolated from environmental samples collected in two French coastal areas, clinical samples, and seafood products imported into France was studied. Polymerase chain reaction (PCR) with two sets of primers was used to detect the hemolysin genes. Most of the clinical isolates (91%) and 1.5% of the isolates from seafood possessed the hemolysin genes. Three and fifteen percent, respectively, of the two groups of environmental strains carried the hemolysin genes depending on the geographic site. The tdh and trh genes play important roles in virulence. Thus, our results indicate that pathogenic V. parahaemolyticus isolates are present in French coastal areas and in seafood imported into France. Furthermore, they may also be present in French seafood products.

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    ABSTRACT: Vibrio parahaemolyticus is a marine microorganism, recognized as an important cause of foodborne illness particularly in Asia, South America and United States. Outbreaks are rarely reported in Europe, but they can occur unexpectedly in relation, among other reasons, to the spread of highly virulent strains. It is known that the risk is proportional to exposure levels to pathogenic V. parahaemolyticus (i.e. carrying the tdh and/or the trh genes) but currently there is a lack of occurrence data for pathogenic V. parahaemolyticus in shellfish production areas of the Member States. In this study a total of 147 samples of bivalve molluscs, from harvesting areas of two Italian regions (Sardinia and Veneto) were analyzed for Escherichia coli and salmonella, according to Reg 2073/2005, and for detection and enumeration of total and toxigenic V. parahaemolyticus strains using a new DNA colony hybridization method. Environmental parameters (water temperature and salinity) were also recorded. Results of E. coli were consistently in agreement with the legislation limits for the harvesting class of origin and Salmonella was detected only in one sample. The average contamination levels for total V. parahaemolyticus were 84 and 73CFU/g respectively for Sardinia and Veneto, with the highest value reaching 8.7×10(3)CFU/g. Nineteen samples (12.9%) resulted positive for the presence of potentially pathogenic V. parahaemolyticus strains, with levels ranging between 10 and 120CFU/g and most of the positive samples (n=17) showing values equal or below 20CFU/g. A significant correlation (r=0.41) was found between water temperature and V. parahaemolyticus levels, as well as with isolation frequency. The data provided in this study on contamination levels of total and potentially pathogenic V. parahaemolyticus, seasonal distribution and correlation with water temperature, will help in defining appropriate monitoring programs and post-harvest policies for this hazard, improving the management of the harvesting areas and the safety of bivalve molluscs.
    International journal of food microbiology 04/2014; · 3.01 Impact Factor
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    ABSTRACT: Genomic DNA of Vibrio parahaemolyticus were characterized by antibiotic resistance, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis. These isolates originated from 3 distantly locations of Selangor, Negeri Sembilan and Melaka (East coastal areas), Malaysia. A total of 44 (n = 44) of tentatively V. parahaemolyticus were also examined for the presence of toxR, tdh and trh gene. Of 44 isolates, 37 were positive towards toxR gene; while, none were positive to tdh and trh gene. Antibiotic resistance analysis showed the V. parahaemolyticus isolates were highly resistant to bacitracin (92 %, 34/37) and penicillin (89 %, 33/37) followed by resistance towards ampicillin (68 %, 25/37), cefuroxime (38 %, 14/37), amikacin (6 %, 2/37) and ceftazidime (14 %, 5/37). None of the V. parahaemolyticus isolates were resistant towards chloramphenicol, ciprofloxacin, ceftriaxone, enrofloxacin, norfloxacin, streptomycin and vancomycin. Antibiogram patterns exhibited, 9 patterns and phenotypically less heterogenous when compared to PCR-based techniques using ERIC- and RAPD-PCR. The results of the ERIC- and RAPD-PCR were analyzed using GelCompare software. ERIC-PCR with primers ERIC1R and ERIC2 discriminated the V. parahaemolyticus isolates into 6 clusters and 21 single isolates at a similarity level of 80 %. While, RAPD-PCR with primer Gen8 discriminated the V. parahaemolyticus isolates into 11 clusters and 10 single isolates and Gen9 into 8 clusters and 16 single isolates at the same similarity level examined. Results in the presence study demonstrated combination of phenotypically and genotypically methods show a wide heterogeneity among cockle isolates of V. parahaemolyticus.
    World Journal of Microbiology and Biotechnology (Formerly MIRCEN Journal of Applied Microbiology and Biotechnology) 09/2013; · 1.35 Impact Factor
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    ABSTRACT: In the present work, we examined 120 shellfish samples (40 each of shrimp, crab and cockle) collected from different fish shops in Mansoura city, Egypt, for the presence of potentially pathogenic strains of Vibrio parahaemolyticus. The conventional method as exemplified by biochemical means indicated that 40 (33.3%) of samples were positive for V. parahaemolyticus. Molecular means as represented by PCR, however, verified that only 20 (16.7%) shellfish samples were positive for V. parahaemolyticus. These 20 positive samples were distributed as 9, 8 and 3 of shrimp, crab and cockle, respectively. Biochemical analyses of the recovered 143 presumptive V. parahaemolyticus colonies indicated that 89 isolates were identified as V. parahaemolyticus. PCR analysis, for the presence of the species-specific toxR gene, indicated that only 27 (30.34%) out of these 89 isolates were verified as V. parahaemolyticus. These molecularly verified 27 strains were distributed as 14, 10 and 3 isolates from the examined shrimp, crab and cockle samples, respectively. Out of the 27 molecularly identified isolates, three (11%) strains were verified to be potentially pathogenic based on detection of tdh and/or trh virulent genes. One of these 3 strains that derived from shrimp was positive for both tdh and trh. The second strain (derived from cockle) was positive for tdh only, while the third one (derived from shrimp) was positive for trh only. The two strains that were positive for tdh, were also verified to be positive for Kanagawa reaction. This study concluded that the examined shellfish may carry the potential human health risk associated with the presence of pathogenic V. parahaemolyticus and that the reliable molecular detection methods should be included in the routine seafood examination in addition to the conventional bacteriological methods.
    Food Control. 10/2013; 33(2):399–405.


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Jun 2, 2014