The hot oyster: levels of virulent Vibrio parahaemolyticus strains in individual oysters.
Vibrio parahaemolyticus is the leading cause of seafood-associated gastroenteritis and is most commonly transmitted by raw oysters. Consequently, detection of virulent strains of this organism in oysters is a primary concern for seafood safety. Vibrio parahaemolyticus levels were determined in 110 individual oysters harvested from two sampling sites in SC, USA. The majority of oysters (98%) contained low levels of presumptive V. parahaemolyticus However, two healthy oysters contained presumptive V. parahaemolyticus numbers that were unusually high. These two 'hot' oysters contained levels of presumptive V. parahaemolyticus within the gills that were ∼100-fold higher than the average for other oysters collected at the same date and location. Current V. parahaemolyticus detection practices require homogenizing a dozen oysters pooled together to determine V. parahaemolyticus numbers, a procedure that would dilute out V. parahaemolyticus in these 'hot' oysters. This study demonstrates the variability of V. parahaemolyticus densities taken from healthy, neighboring individual oysters in the environment. Additionally, environmental V parahaemolyticus isolates were screened for the virulence-related genes, tdh and trh, using improved polymerase chain reaction primers and protocols. We detected these genes, previously thought to be rare in environmental isolates, in approximately half of the oyster isolates.
Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
Savannah L
SL
Klein
Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA lovell@biol.sc.edu.
Charles R
CR
Lovell
D000818:Animals; D017931:DNA Primers; D005506:Food Contamination; D006801:Humans; D010125:Ostreidae / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D017747:Seafood / Q000382:microbiology / Q000706:statistics & numerical data; D012758:Shellfish / Q000382:microbiology / Q000706:statistics & numerical data; D014736:Vibrio parahaemolyticus / Q000254:growth & development* / Q000302:isolation & purification; D014774:Virulence; D014871:Water Microbiology
D017931:DNA Primers
Crassostrea virginica; Vibrio parahaemolyticus; seafood, gastroenteritis; tdh; trh