Bacteriophage as models for virus removal from Pacific oysters (<i>Crassostrea gigas</i>) during re-laying

Humphrey, T. J.; Martin, Keith L.

doi:10.1017/s0950268800057034

Cited by 16 publications

(7 citation statements)

References 15 publications

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“…The accumulation of microbial contaminants by mussels was similar to patterns reported previously for bivalve shellfish (14). Both E. coli and F ϩ bacteriophage were accumulated rapidly over 24 h, thereafter reaching an apparent equilibrium, suggesting that similar mechanisms are responsible for both viral and bacterial accumulation in bivalve shellfish.…”

Section: Discussionsupporting

confidence: 84%

Behavior of Escherichia coli and male-specific bacteriophage in environmentally contaminated bivalve molluscs before and after depuration

Doré

Lees

1995

Appl Environ Microbiol

121

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We monitored the differential reduction rates and elimination patterns of Escherichia coli and male-specific (F ؉) bacteriophage during UV depuration for 48 h in oysters (Crassostrea gigas) and mussels (Mytilus edulis) contaminated by short-term (1 to 3 weeks) and long-term (more than 6 months) exposure to sewage in the marine environment. The time taken to reduce levels of E. coli by 90% was 6.5 h or less in all cases. In contrast, the amounts of time needed to reduce levels of F ؉ bacteriophage by 90% were considerably longer: 47.3 and 41.3 h (after short-and long-term exposures, respectively) in mussels and 54.6 and 60.8 h (after short-and long-term exposures, respectively) in oysters. No differences in the rates of reduction of indicators of viral pollution following exposure of the shellfish to either short-or long-term sewage contamination were observed. Further experiments were conducted with mussels to determine the relative distributions of E. coli and F ؉ bacteriophage in tissue before and during depuration. Prior to depuration the majority of E. coli organisms (90.1%) and F ؉ bacteriophage (87.3%) were detected in the digestive tract (i.e., the digestive gland and intestine). E. coli and F ؉ bacteriophage were reduced in all tissues except the digestive gland to undetectable levels following depuration for 48 h. Within the digestive gland, levels of F ؉ bacteriophage were reduced to 30% of initial levels, whereas E. coli was reduced to undetectable levels. These results confirm previous laboratory studies showing the differential reductions of levels of E. coli and F ؉ bacteriophage during depuration. They also demonstrate that these differential elimination patterns are not affected by the duration of sewage contamination and that F ؉ bacteriophage are retained only in the digestive gland and are not sequestered into other internal tissues.

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Section: Discussionsupporting

confidence: 84%

Behavior of Escherichia coli and male-specific bacteriophage in environmentally contaminated bivalve molluscs before and after depuration

Doré

Lees

1995

Appl Environ Microbiol

121

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“…This contradiction may be due to the degree of pollution, time of exposure and the molluscan species. Many studies reported the ability of bivalves to accumulate bacteria (Humphrey and Martin, 1993;El-Shenawy, 2004). At the same time, they can purge themselves of bacterial contaminants within 48 h, or they may be held up to 72 h in some cases (Dore and Lees, 1995).…”

Section: Discussionmentioning

confidence: 99%

The effect of depuration on heavy metals, petroleum hydrocarbons, and microbial contamination levels in Paphia undulata (Bivalvia: Veneridae)

El-Gamal¹

2011

CZECH J ANIM SCI

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ABSTRACT:The depuration of 8 heavy metals (Zn, Pb, Ni, Mn, Cu, Cr, Co and Cd), total petroleum hydrocarbons and pathogenic bacteria of Paphia undulata was tested and the survival of depurated clams was evaluated. Investigated samples were collected from Ismailia, Egypt. The initial metal concentrations were significantly higher in the whole soft tissues than in water and sediment except for Mn. After 24 h depuration, Zn, Pb, Ni, Mn, Cu, Cr and Cd were significantly reduced to 44, 23, 25, 17, 61, 41, and 75%, respectively. After three days of depuration the reduction was significant only for Cu, Cr, Co and Cd (27, 15, 23 and 52%, respectively). The total petroleum hydrocarbons were reduced significantly to 72% after three days of depuration, while after 24 h they were reduced to 90% compared to their initial concentrations. Four pathogenic bacteria were identified in the soft tissues of P. undulata (Vibrio sp., Shigella sp., Escherichia coli and Salmonella sp.). After one-day depuration the results evidenced the mean microbial reduction to 75, 31, 68, and 36%, respectively, compared to their initial counts. After three days of depuration the counts of Vibrio sp. and Salmonella sp. were reduced to 3% and 8%, respectively, while Escherichia coli was not detected on the third day. Shigella sp. was increased by 22% compared to the first day of depuration. The viability and mortality were not influenced by the depurative treatment.

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“…In the present study the counts of total bacteria, fecal coliforms, pathogenic bacteria, and coliphage were monitored to assess the efficiency of microbial depuration of bivalves. Humphrey and Martin (1993) and Formiga-Cruz (2003) previously reported that the bivalve had the ability to accumulate a microbial contaminant. The results of the present work indicated that bivalves collected from the moderately polluted site (II) reached acceptable bacterial counts according to international standards (European Communities, 1991).…”

Section: Discussionmentioning

confidence: 99%

Heavy‐metal and microbial depuration of the clam Ruditapes decussatus and its effect on bivalve behavior and physiology

El-Shenawy

2004

Environmental Toxicology

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The bivalve Ruditapes decussatus was evaluated as a possible biomonitor of heavy-metal contamination. Concentrations of copper (Cu), cobalt (Co), iron (Fe), nickel (Ni), and manganese (Mn) were measured in R. decussatus. Water and sediment samples were collected at two stations of Timsah Lake in Ismailia, Egypt, from October to November 2002, using atomic absorption spectrophotometry (AAS). Results from the heavy-metal and microbial analyses indicated that site II was less contaminated than site I. The bivalve showed accumulation of metals, with a bioaccumulation factor (BAF) greater than 4. The bioaccumulation of metals varied strongly according to the sampling site. After 48 h of depuration, Fe, Ni, Co, Cu, and Mn were reduced significantly, to 46.8% and 47.7%, 19.9% and 20.3%, 27.3% and 27.9%, 35.9% and 36.6%, and 18.2% and 26.6%, compared with the initial concentrations, in clam tissue at the two stations. In bivalves from site II the counts of total bacteria, fecal coliforms, and bacterial pathogens were reduced by more than 90%, whereas phage counts were only reduced by 56% after 4 days of depuration. The depuration of bivalves collected from the heavily polluted site (I) was not effective, as coliforms were reduced only by 85% after 4 days, whereas counts of pathogens and pathogenic indicators such as Vibrio, fecal Streptococcus, and coliphage decreased to less than 50% of the initial concentration. The time necessary to decrease contamination to 10%, 50%, and 90% for clams at both stations was consistently shorter for heavy metals than for microorganisms. Investigation of the effects of heavy-metal and microbiological depuration on valve movement and physiological rates (oxygen consumption and ammonia excretion) was carried out on R. decussatus to test the utility of physiological stress indices in assessing the health of depurated animals. Clams in the experimental tanks exhibited various states of activity, which were rated by identifying and scoring (0-4) the different parameters, including shell gap, siphon extension, and foot protrusion. Moreover, an increase in ammonia excretion was usually associated with an increase in respiration rate. The oxygen-to-nitrogen ratio provided a sensitive indicator of bivalve health. It can be concluded that shellfish monitoring and depuration data depended on the initial concentration of the pollutants. There were differences in the physiological responses of clams from the two sites during the periods of pre- and postdepuration of the contaminants. There was a significant correlation between reduction of metal concentration in clam tissue and enhancement of valve movement, as well as activity and increasing respiration rate.

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Bacteriophage as models for virus removal from Pacific oysters (Crassostrea gigas) during re-laying

Cited by 16 publications

References 15 publications

Behavior of Escherichia coli and male-specific bacteriophage in environmentally contaminated bivalve molluscs before and after depuration

Behavior of Escherichia coli and male-specific bacteriophage in environmentally contaminated bivalve molluscs before and after depuration

The effect of depuration on heavy metals, petroleum hydrocarbons, and microbial contamination levels in Paphia undulata (Bivalvia: Veneridae)

Heavy‐metal and microbial depuration of the clam Ruditapes decussatus and its effect on bivalve behavior and physiology

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