Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity

Froelich, Brett; Williams, Tiffany C.; Noble, Rachel T.; Oliver, James D.

doi:10.1128/aem.07855-11

Cited by 47 publications

(45 citation statements)

References 36 publications

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“…When the drought ended in 2010, the salinity returned to ca. 15‰, and we were again able to routinely isolate V. vulnificus from these waters and oysters (93). Such findings are consistent with studies suggesting "relaying" oysters from low to high salinity waters significantly reduces the V. vulnificus load (94,95).…”

Section: Importance Of Salinitysupporting

confidence: 78%

The Biology of Vibrio vulnificus

2015

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Vibrio vulnificus, carrying a 50% fatality rate, is the most deadly of the foodborne pathogens. It occurs in estuarine and coastal waters and it is found in especially high numbers in oysters and other molluscan shellfish. The biology of V. vulnificus, including its ecology, pathogenesis, and molecular genetics, has been described in numerous reviews. This article provides a brief summary of some of the key aspects of this important human pathogen, including information on biotypes and genotypes, virulence factors, risk factor requirements and the role of iron in disease, association with oysters, geographic distribution, importance of salinity and water temperature, increasing incidence associated with global warming. This article includes some of our findings as presented at the

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Section: Importance Of Salinitysupporting

confidence: 78%

The Biology of Vibrio vulnificus

2015

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“…Water temperatures and TSS levels were positively correlated with oyster and water V. vulnificus levels, while salinity was negatively correlated. For both oysters and water, the levels of V. vulnificus appeared to increase to ϳ17% salinity and then began to decrease, as commonly reported (10,(31)(32)(33)(34). Clam concentrations remained mostly stable as salinity increased.…”

Section: Discussionsupporting

confidence: 58%

“…in oysters remained mostly flat along the salinity gradient, with salt-tolerant Vibrio spp. and other bacteria likely occupying oyster matrices vacated by less-salt-tolerant species such as V. vulnificus (31,32). In clams, Vibrio levels began increasing at ϳ25% salinity; currently, we have no explanation for this observation.…”

Section: Discussionmentioning

confidence: 62%

Differences in Abundances of Total Vibrio spp., V. vulnificus, and V. parahaemolyticus in Clams and Oysters in North Carolina

Froelich

Phippen

Fowler

et al. 2017

Appl Environ Microbiol

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Filter feeding shellfish can concentrate pathogenic bacteria, including Vibrio vulnificus and Vibrio parahaemolyticus, as much as 100-fold from the overlying water. These shellfish, especially clams and oysters, are often consumed raw, providing a route of entry for concentrated doses of pathogenic bacteria into the human body. The numbers of foodborne infections with these microbes are increasing, and a better understanding of the conditions that might trigger elevated concentrations of these bacteria in seafood is needed. In addition, if bacterial concentrations in water are correlated with those in shellfish, then sampling regimens could be simplified, as water samples can be more rapidly and easily obtained. After sampling of oysters and clams, either simultaneously or separately, for over 2 years, it was concluded that while Vibrio concentrations in oysters and water were related, this was not the case for levels in clams and water. When clams and oysters were collected simultaneously from the same site, the clams were found to have lower Vibrio levels than the oysters. Furthermore, the environmental parameters that were correlated with levels of Vibrio spp. in oysters and water were found to be quite different from those that were correlated with levels of Vibrio spp. in clams.IMPORTANCE This study shows that clams are a potential source of infection in North Carolina, especially for V. parahaemolyticus. These findings also highlight the need for clam-specific environmental research to develop accurate Vibrio abundance models and to broaden the ecological understanding of clam-Vibrio interactions. This is especially relevant as foodborne Vibrio infections from clams are being reported.KEYWORDS clams, ecology, food, oysters, shellfish, Vibrio A n estimated 84,000 people contract foodborne Vibrio infections each year in the United States, resulting in 500 hospitalizations and 100 deaths (1, 2). Unlike most other major foodborne bacterial pathogens, the number of cases caused by Vibrio spp. is increasing and currently is the highest since national reporting began (2, 3). While at least 12 Vibrio spp. are potentially pathogenic to humans, the two foodborne Vibrio spp. that cause the most infections and the most deaths in the United States are Vibrio parahaemolyticus and Vibrio vulnificus, respectively (2, 4).V. vulnificus is the single most fatal foodborne pathogen in the United States, and perhaps the world (4), accounting for 95% of all U.S. seafood-related deaths, with a fatality rate approaching 50% (5). Infections resulting from ingestion typically produce symptoms such as fever, chills, nausea, abdominal pain, hypotension, and the development of secondary lesions on the extremities (5, 6). V. parahaemolyticus infections are

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“…4) away from the discharge. These results agree with those of previous studies (Kelly, 1982;Singleton et al, 1982;O'neill et al, 1992;Hoi et al, 1998;DePaola et al, 2003;Pfeffer et al, 2003;Lyons et al, 2007;Froelich et al, 2012) that showed similar relationships between the water quality parameters and Vibrionaceae concentrations in oysters observed in our study.…”

Section: Case Studies-oyster Safety For Consumptionsupporting

confidence: 83%

Effects of Microbial and Heavy Metal Contaminants on Environmental/Ecological Health and Revitalization of Coastal Ecosystems in Delaware Bay

Ozbay

Chintapenta

Cannon

et al. 2017

Front. Environ. Sci.

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The presence of heavy metals, excess nutrients, and microbial contaminants in aquatic systems of coastal Delaware has become a public concern as human population increases and land development continues. Delaware's coastal lagoons have been subjected to problems commonly shared by other coastal Mid-Atlantic states: turbidity, sedimentation, eutrophication, periodic hypoxic/anoxic conditions, toxic substances, and high bacterial levels. The cumulative impact of pollutants from run-off and point sources has degraded water quality, reduced the diversity and abundance of various fish species, invertebrates, and submerged aquatic vegetation. The effects are especially pronounced within the manmade dead end canal systems. In this article, we present selected case studies conducted in the Delaware Inland Bays. Due to the ecological services provided by bivalves, our studies in Delaware Inland Bays are geared toward oysters with special focus on the microbial loads followed by the water quality assessments of the bay. The relationships between oysters (Crassostrea virginica), microbial loads and nutrient levels in the water were investigated. The heavy metal levels monitored further away from the waste water treatment plant in the inland bays are marginally higher than the recommended EPA limits. Also, our studies confirmed that aerobic bacteria and Vibrionaceae levels are salinity dependent. Total bacteria in oysters increased when nitrate and total suspended solids increased in the waters. Studies such as these are important because every year millions of Americans consume raw oysters. Data collected over the last 10 years from our studies may be used to build a predictive index of conditions that are favorable for the proliferation of human pathogenic bacteria. Results from this study will benefit the local community by helping them understand the importance of oyster aquaculture and safe consumption of oysters while making them appreciate their ecological and commercial values. This will also be of tremendous help to the commercial shellfish aquaculture farms to predict poor conditions to prevent oysters' consumption when bacterial levels are high in water.

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Apparent Loss of Vibrio vulnificus from North Carolina Oysters Coincides with a Drought-Induced Increase in Salinity

Cited by 47 publications

References 36 publications

The Biology of Vibrio vulnificus

The Biology of Vibrio vulnificus

Differences in Abundances of Total Vibrio spp., V. vulnificus, and V. parahaemolyticus in Clams and Oysters in North Carolina

Effects of Microbial and Heavy Metal Contaminants on Environmental/Ecological Health and Revitalization of Coastal Ecosystems in Delaware Bay

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