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.

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.

scholarly journals Integration of Vibrio vulnificus into Marine Aggregates and Its Subsequent Uptake by Crassostrea virginica Oysters

2012 ◽  
Vol 79 (5) ◽  
pp. 1454-1458 ◽  
Author(s):  
Brett Froelich ◽  
Mesrop Ayrapetyan ◽  
James D. Oliver
Keyword(s):  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Bacterial Pathogen ◽  
Surrounding Water ◽  
Content Type ◽  
Marine Aggregates

ABSTRACTMarine aggregates are naturally forming conglomerations of larvacean houses, phytoplankton, microbes, and inorganics adhered together by exocellular polymers. In this study, we showin vitrothat the bacterial pathogenVibrio vulnificuscan be concentrated into laboratory-generated aggregates from surrounding water. We further show that environmental (E-genotype) strains exhibit significantly more integration into these aggregates than clinical (C-genotype) strains. Experiments where marine aggregates with attachedV. vulnificuscells were fed to oysters (Crassostrea virginica) resulted in greater uptake of both C and E types than nonaggregated controls. When C- and E-genotype strains were cocultured in competitive experiments, the aggregated E-genotype strains exhibited significantly greater uptake by oyster than the C-genotype strains.

scholarly journals Factors Influencing In Vitro Killing of Bacteria by Hemocytes of the Eastern Oyster (Crassostrea virginica)

1999 ◽  
Vol 65 (7) ◽  
pp. 3015-3020 ◽  
Author(s):  
Fred J. Genthner ◽  
Aswani K. Volety ◽  
Leah M. Oliver ◽  
William S. Fisher
Keyword(s):  
Bactericidal Activity ◽  
Vibrio Vulnificus ◽  
Hydrolytic Enzymes ◽  
Eastern Oyster ◽  
In Vitro Tests ◽  
Wild Type ◽  
Bacterial Strains ◽  
Dye Reduction ◽  
Colonial Morphology

ABSTRACT A tetrazolium dye reduction assay was used to study factors governing the killing of bacteria by oyster hemocytes. In vitro tests were performed on bacterial strains by using hemocytes from oysters collected from the same location in winter and summer. Vibrio parahaemolyticus strains, altered in motility or colonial morphology (opaque and translucent), and Listeria monocytogenes mutants lacking catalase, superoxide dismutase, hemolysin, and phospholipase activities were examined in winter and summer. Vibrio vulnificus strains, opaque and translucent (with and without capsules), were examined only in summer. AmongV. parahaemolyticus and L. monocytogenes, significantly (P < 0.05) higher levels of killing by hemocytes were observed in summer than in winter. L. monocytogenes was more resistant than V. parahaemolyticus or V. vulnificus to the bactericidal activity of hemocytes. In winter, both translucent strains of V. parahaemolyticus showed significantly (P < 0.05) higher susceptibility to killing by hemocytes than did the wild-type opaque strain. In summer, only one of the V. parahaemolyticus translucent strains showed significantly (P < 0.05) higher susceptibility to killing by hemocytes than did the wild-type opaque strain. No significant differences (P > 0.05) in killing by hemocytes were observed between opaque (encapsulated) and translucent (nonencapsulated) pairs of V. vulnificus. Activities of 19 hydrolytic enzymes were measured in oyster hemolymph collected in winter and summer. Only one enzyme, esterase (C4), showed a seasonal difference in activity (higher in winter than in summer). These results suggest that differences existed between bacterial genera in their ability to evade killing by oyster hemocytes, that a trait(s) associated with the opaque phenotype may have enabled V. parahaemolyticus to evade killing by the oyster’s cellular defense, and that bactericidal activity of hemocytes was greater in summer than in winter.

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.

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.

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
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