Interaction of Vibrio vulnificus and the Eastern Oyster, Crassostrea virginica

1994 ◽  
Vol 57 (3) ◽  
pp. 224-228 ◽  
Author(s):  
TRUDI N. GROUBERT ◽  
JAMES D. OLIVER
Keyword(s):  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Health Hazard ◽  
Effective Means ◽  
Ultra Violet ◽  
Eastern Oyster ◽  
Human Pathogen ◽  
Specific Identification ◽  
Conversion Rates ◽  
Differential Medium

The estuarine bacterium, Vibrio vulnificus, is a human pathogen associated with the consumption of raw oysters. To date, no effective means exists for the elimination of this health hazard in oysters meant for raw consumption. The purpose of this study was to investígate the interaction between V. vulnificus and the eastern oyster. These studies were facilitated through the use of a strain of V. vulnificus containing a TnphoA transposon that allowed specific identification of the bacterium on a selective and differential médium. In studies employing ultra-violet assisted (UV-assisted) depuration, no differences were found in the oysters of the encapsulated (virulent) and nonencapsulated (avirulent) morphotypes of V. vulnificus. Both types were readily depurated from the oysters, while a naturally obtained microflora was shown not to depurate. Virulence of V. vulnificus and conversion rates between the virulent and avirulent morphotypes of this bacterium were found to be unchanged by oyster passage.

Use of Diacetyl To Reduce the Load of Vibrio vulnificus in the Eastern Oyster, Crassostrea virginica

2003 ◽  
Vol 66 (1) ◽  
pp. 38-43 ◽  
Author(s):  
J. M. BIRKENHAUER ◽  
J. D. OLIVER
Keyword(s):  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Natural Populations ◽  
Eastern Oyster ◽  
Human Pathogen ◽  
Highly Virulent

Vibrio vulnificus is a highly virulent human pathogen that occurs naturally among the microflora of oysters. This organism has two portals of entry into humans, one of which is ingestion. Oysters containing V. vulnificus consumed in a raw or undercooked state often serve as a vehicle for the transmission of this organism. Previous studies conducted in our laboratory have examined various generally recognized as safe compounds and have determined that diacetyl, a component of butter, is among the most effective of these compounds in reducing loads of V. vulnificus in oysters. The purpose of this study was to further examine the role of diacetyl, along with that of depuration, in reducing loads of V. vulnificus. Shellstock oysters were treated with various concentrations of diacetyl, and we found that many of the oysters ceased pumping when diacetyl was added. The data obtained in this study indicated that treatment with diacetyl is ineffective; however, any reduction in V. vulnificus numbers may be masked when groups of oysters, some of which may not have taken up diacetyl, are sampled. We then investigated the efficacy of diacetyl in lowering levels of V. vulnificus in shucked oysters. Diacetyl was found to significantly reduce the load of V. vulnificus in shucked oysters containing natural populations. Overall, it appears that treatment with diacetyl is ineffective for shellstock oysters, although it has potential for use in reducing loads of V. vulnificus in shucked oysters.

Vibrio vulnificus Load Reduction in Oysters after Combined Exposure to Vibrio vulnificus–Specific Bacteriophage and to an Oyster Extract Component†

2005 ◽  
Vol 68 (6) ◽  
pp. 1188-1191 ◽  
Author(s):  
WILLIAM PELON ◽  
RONALD B. LUFTIG ◽  
KENNETH H. JOHNSTON
Keyword(s):  
Health Risk ◽  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Load Reduction ◽  
Combined Exposure ◽  
In Vitro System ◽  
Iron Deficient ◽  
Specific Bacteriophage

Oysters infected with Vibrio vulnificus can present a serious health risk to diabetic, immunocompromised, and iron-deficient individuals. Numerous studies have been conducted with the goal of eliminating this organism from raw oysters. We utilized two natural oyster-associated components: pooled Vibrio vulnificus–specific bacteriophage and an extract of the eastern oyster (Crassostrea virginica) that contains an antimicrobial component we named anti–Vibrio vulnificus factor, which is bactericidal for V. vulnificus. Although each component alone can reduce V. vulnificus numbers independently, the simultaneous use of both components in an in vitro system successfully more effectively reduced V. vulnificus bacterial loads.

scholarly journals Perkinsus marinus Extracellular Protease Modulates Survival of Vibrio vulnificus in Eastern Oyster (Crassostrea virginica) Hemocytes

1999 ◽  
Vol 65 (9) ◽  
pp. 4261-4263 ◽  
Author(s):  
B. D. Tall ◽  
J. F. La Peyre ◽  
J. W. Bier ◽  
M. D. Miliotis ◽  
D. E. Hanes ◽  
...  
Keyword(s):  
Serine Protease ◽  
Crassostrea Virginica ◽  
Time Course ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Intracellular Survival ◽  
Extracellular Protease ◽  
Perkinsus Marinus ◽  
In Vitro Effects

ABSTRACT The in vitro effects of the Perkinsus marinus serine protease on the intracellular survival of Vibrio vulnificusin oyster hemocytes were examined by using a time-course gentamicin internalization assay. Results showed that protease-treated hemocytes were initially slower to internalize V. vulnificus than untreated hemocytes. After 1 h, the elimination of V. vulnificus by treated hemocytes was significantly suppressed compared with hemocytes infected with invasive and noninvasive controls. Our data suggest that the serine protease produced byP. marinus suppresses the vibriocidal activity of oyster hemocytes to effectively eliminate V. vulnificus, potentially leading to conditions favoring higher numbers of vibrios in oyster tissues.

Long-Term Depuration of Crassostrea virginica Oysters at Different Salinities and Temperatures Changes Vibrio vulnificus Counts and Microbiological Profile

2018 ◽  
Vol 82 (1) ◽  
pp. 22-29
Author(s):  
OLEKSANDR TOKARSKYY ◽  
DOUGLAS L. MARSHALL ◽  
JEFF DILLON ◽  
LINDA S. ANDREWS
Keyword(s):  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Population Count ◽  
Psychrotrophic Bacteria ◽  
Log Reduction ◽  
Long Duration ◽  
Plate Counts ◽  
Vibrio Spp

ABSTRACT Previous short-duration depuration studies with the eastern oyster (Crassostrea virginica) demonstrated difficulty in achieving significant naturally incurred Vibrio vulnificus population count reductions. The present study used long-duration depuration (14 days) at controlled temperatures (10 or 22°C) and salinities (12, 16, or 20 mg/g). All depuration temperature–salinity combinations significantly reduced V. vulnificus counts, with greatest reductions seen in 12 mg/g, 10°C seawater (2.7-log CFU/g reduction) and in 20 mg/g, 22°C seawater (2.8-log reduction). Mesophilic vibrios dominated the overall microflora of freshly harvested oysters, whereas refrigerated storage selected for psychrotrophic bacteria (Pseudomonas spp., Aeromonas spp., Shewanella spp., Psychrobacter spp.) as well as did depuration at 10°C (Pseudoalteromonas spp., Shewanella spp., Vibrio spp.). Depuration at 22°C retained dominance of mesophilic vibrios, including pathogenic species, followed by Shewanella spp., Pseudoalteromonas spp., and Photobacterium spp. Although aerobic plate counts were lower in 22°C depurated oysters (5.0 log versus 6.0 log) compared with 10°C, depuration at 10°C offered greater V. vulnificus population reductions than depuration at 22°C. This advantage was only seen at 12 mg/g salinity, with no impact at 16 and 20 mg/g salinities. No depuration treatment reduced V. vulnificus counts to nondetectable levels. Use of prolonged depuration may be a helpful intervention to control V. vulnificus populations in oysters.

Effective reduction of Vibrio vulnificus in the Eastern oyster (Crassostrea virginica) using high salinity depuration

2013 ◽  
Vol 34 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Andrea M. Larsen ◽  
F. Scott Rikard ◽  
William C. Walton ◽  
Covadonga R. Arias
Keyword(s):  
Crassostrea Virginica ◽  
High Salinity ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Effective Reduction

Effectiveness of Icing as a Postharvest Treatment for Control of Vibrio vulnificus and Vibrio parahaemolyticus in the Eastern Oyster (Crassostrea virginica)

2008 ◽  
Vol 71 (7) ◽  
pp. 1475-1480 ◽  
Author(s):  
KEVIN MELODY ◽  
RESHANI SENEVIRATHNE ◽  
MARLENE JANES ◽  
LEE ANN JAYKUS ◽  
JOHN SUPAN
Keyword(s):  
Crassostrea Virginica ◽  
Cold Storage ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Storage Period ◽  
Eastern Oyster ◽  
Pathogenic Vibrio ◽  
Postharvest Treatment ◽  
Shellfish Sanitation ◽  
Vibrio Spp

The focus of this research was to investigate the efficacy of icing as a postharvest treatment for reduction of the levels of Vibrio vulnificus and Vibrio parahaemolyticus in commercial quantities of shellstock oysters. The experiments were conducted in June and August of 2006 and consisted of the following treatments: (i) on-board icing immediately after harvest; (ii) dockside icing approximately 1 to 2 h prior to shipment; and (iii) no icing (control). Changes in the levels of pathogenic Vibrio spp. during wholesale and retail handling for 2 weeks postharvest were also monitored. On-board icing achieved temperature reductions in all sacks in accordance with the National Shellfish Sanitation Program standard, but dockside icing did not meet this standard. Based on one-way analysis of variance, the only statistically significant relationship between Vibrio levels and treatment occurred for samples harvested in August; in this case, the levels of V. vulnificus in the noniced oysters were significantly higher (P < 0.05) than were the levels in the samples iced on-board. When analyzing counts over the 14-day storage period, using factorial analysis, there were statistically significant differences in V. vulnificus and V. parahaemolyticus levels by sample date and/or treatment (P < 0.05), but these relationships were not consistent. Treated (iced) oysters had significantly higher gaping (approximately 20%) after 1 week in cold storage than did noniced oysters (approximately 10%) and gaping increased significantly by day 14 of commercial storage. On-board and dockside icing did not predictably reduce the levels of V. vulnificus or V. parahaemolyticus in oysters, and icing negatively impacted oyster survival during subsequent cold storage.

Effects of resuspension of eastern oyster Crassostrea virginica biodeposits on phytoplankton community structure

2020 ◽  
Vol 640 ◽  
pp. 79-105
Author(s):  
ET Porter ◽  
E Robins ◽  
S Davis ◽  
R Lacouture ◽  
JC Cornwell
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
Crassostrea Virginica ◽  
Skeletonema Costatum ◽  
Eastern Oyster ◽  
Energy Dissipation Rate ◽  
Negative Effects ◽  
Cell Densities ◽  
Sediment Bottom ◽  
Nitrite Nitrate

Anthropogenic disturbances in the Chesapeake Bay (USA) have depleted eastern oyster Crassostrea virginica abundance and altered the estuary’s environment and water quality. Efforts to rehabilitate oyster populations are underway; however, the effect of oyster biodeposits on water quality and plankton community structure are not clear. In July 2017, we used 6 shear turbulence resuspension mesocosms (STURMs) to determine differences in plankton composition with and without the daily addition of oyster biodeposits to a muddy sediment bottom. STURM systems had a volume-weighted root mean square turbulent velocity of 1.08 cm s-1, energy dissipation rate of ~0.08 cm2 s-3, and bottom shear stress of ~0.36-0.51 Pa during mixing-on periods during 4 wk of tidal resuspension. Phytoplankton increased their chlorophyll a content in their cells in response to low light in tanks with biodeposits. The diatom Skeletonema costatum bloomed and had significantly longer chains in tanks without biodeposits. These tanks also had significantly lower concentrations of total suspended solids, zooplankton carbon, and nitrite +nitrate, and higher phytoplankton carbon concentrations. Results suggest that the absence of biodeposit resuspension initiates nitrogen uptake for diatom reproduction, increasing the cell densities of S. costatum. The low abundance of the zooplankton population in non-biodeposit tanks suggests an inability of zooplankton to graze on S. costatum and negative effects of S. costatum on zooplankton. A high abundance of the copepod Acartia tonsa in biodeposit tanks may have reduced S. costatum chain length. Oyster biodeposit addition and resuspension efficiently transferred phytoplankton carbon to zooplankton carbon, thus supporting the food web in the estuary.

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