Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 9, 2443
eCollection

Occurrence of Bacterial Pathogens and Human Noroviruses in Shellfish-Harvesting Areas and Their Catchments in France

Affiliations

Occurrence of Bacterial Pathogens and Human Noroviruses in Shellfish-Harvesting Areas and Their Catchments in France

Alain Rincé et al. Front Microbiol.

Abstract

During a 2-year study, the presence of human pathogenic bacteria and noroviruses was investigated in shellfish, seawater and/or surface sediments collected from three French coastal shellfish-harvesting areas as well as in freshwaters from the corresponding upstream catchments. Bacteria isolated from these samples were further analyzed. Escherichia coli isolates classified into the phylogenetic groups B2, or D and enterococci from Enterococcus faecalis and E. faecium species were tested for the presence of virulence genes and for antimicrobial susceptibility. Salmonella members were serotyped and the most abundant serovars (Typhimurium and its monophasic variants and Mbandaka) were genetically characterized by high discriminative subtyping methods. Campylobacter and Vibrio were identified at the species level, and haemolysin-producing Vibrio parahaemolyticus were searched by tdh- and trh- gene detection. Main results showed a low prevalence of Salmonella in shellfish samples where only members of S. Mbandaka were found. Campylobacter were more frequently isolated than Salmonella and a different distribution of Campylobacter species was observed in shellfish compared to rivers, strongly suggesting possible additional inputs of bacteria. Statistical associations between enteric bacteria, human noroviruses (HuNoVs) and concentration of fecal indicator bacteria revealed that the presence of Salmonella was correlated with that of Campylobacter jejuni and/or C. coli as well as to E. coli concentration. A positive correlation was also found between the presence of C. lari and the detection of HuNoVs. This study highlights the importance of simultaneous detection and characterization of enteric and marine pathogenic bacteria and human noroviruses not only in shellfish but also in catchment waters for a hazard assessment associated with microbial contamination of shellfish.

Keywords: Campylobacter; HuNoVs; Salmonella; Vibrio; fecal bacterial indicators; shellfish; water.

Figures

FIGURE 1
FIGURE 1
Location of sampling sites. (A) La Fresnaye (Brittany) site 1. (B) Regnéville sur mer (Normandy) site 2. (C) La Vanlée (Normandy) site 3. (D) Location of studied sites on a map of France. Sampling sites are represented by arrows (water from river and brackish water), circles (shellfish and seawater) and stars (sediment).
FIGURE 2
FIGURE 2
Enumeration of fecal indicator bacteria. (A) Boxplots of Escherichia coli concentration in water and shellfish. (B) Boxplots of Enterococci concentration in water. Boxplots show the minimum, the 25th percentile, the median, the 75th percentile and the maximum concentration. For water samples, 1E, 2D, and 3C correspond to seawater and others to river or brackish water. For shellfish samples, 1F, 1H, 2E, and 3D correspond to oysters, 1G, 1I, 2F, and 3E to mussels, and 1J and 2G to cockles.
FIGURE 3
FIGURE 3
Distribution of E. coli isolates according to their phylogenetic group. The phylogenetic groups A, B1, B2, and D are represented by hatched, white, gray and black bars, respectively. S, shellfish; SW, seawater; W, river or brackish water.
FIGURE 4
FIGURE 4
Distribution of the main isolated species. Black, gray and hatched bars represent results from sites 1, 2, and 3, respectively.
FIGURE 5
FIGURE 5
Prevalence and isolation of Salmonella (A) and Campylobacter (B). The prevalence which corresponds to the presence of the invA or ttrBCA genes in selective enrichments for Salmonella or 16S RNA genes in Bolton broth for Campylobacter (dots) and the percentage of samples for which at least one strain was isolated (bars) are indicated as regard to sample type [water from river and brackish water (w), seawater (sw), shellfish (sh), and sediment (sd), site, season, temperature, and precipitation].
FIGURE 6
FIGURE 6
Prevalence and isolation of Vibrio parahaemolyticus, Vp (A), Vibrio cholerae, Vc (B), and Vibrio vulnificus, Vv (C). The prevalence which corresponds to the presence of the toxR gene, the IGS region and the vvhA gene in selective enrichments for Vp, Vc, and Vv, respectively (dots) and the percentage of samples for which at least one strain was isolated (bars) are indicated as regard to sample type [seawater (sw), and shellfish (sh), site, season, temperature, and precipitation].

Similar articles

See all similar articles

Cited by 3 articles

References

    1. Abeyta C., Deeter F. G., Kaysner C. A., Stott R. F., Wekell M. M. (1993). Campylobacter jejuni in a Washington state shellfish growing bed associated with illness. J. Food Prot. 56 323–325. 10.4315/0362-028X-56.4.323 - DOI
    1. AFNOR-NF-V-08-106:2010 (2010). Microbiologie des aliments: Dnombrement des E. coli présumés dans les coquillages vivants -Technique indirecte par impédancemétrie directe.
    1. Amagliani G., Brandi G., Schiavano G. F. (2012). Incidence and role of Salmonella in seafood safety. Food Res. Int. 45 780–788. 10.1016/j.foodres.2011.06.022 - DOI
    1. Andrade V. C., Zampieri B. B., Ballesteros E. R., Pinto A. B., de Oliveira A. J. (2015). Densities and antimicrobial resistance of Escherichia coli isolated from marine waters and beach sands. Environ. Monit. Assess. 187:342. 10.1007/s10661-015-4573-8 - DOI - PubMed
    1. Atmar R. L., Opekun A. R., Gilger M. A., Estes M. K., Crawford S. E., Neill F. H., et al. (2014). Determination of the 50% human infectious dose for Norwalk virus. J. Infect. Dis. 209 1016–1022. 10.1093/infdis/jit620 - DOI - PMC - PubMed

LinkOut - more resources

Feedback