What question did this study set out to answer?

The study aims to understand how two strains of Vibrio parahaemolyticus accumulate and depurate in blue mussels under controlled conditions.

March 10, 2026Open Access

Accumulation and strain-dependent depuration of tdh- and trh-positive Vibrio parahaemolyticus in blue mussels (Mytilus edulis) under closed conditions

Key Points

The study aims to understand how two strains of Vibrio parahaemolyticus accumulate and depurate in blue mussels under controlled conditions.
Exposed blue mussels to varying concentrations of Vibrio parahaemolyticus for 48 hours.
Measured accumulation of bacteria in mussel tissue post-exposure.
Conducted depuration trials for 72 hours after exposure to different bacterial loads.
Compared accumulation and depuration between clinical and environmental strains.
Accumulation in mussels increased significantly with higher doses and longer exposure times.
Both strains reached similar tissue concentrations after 48 hours.
Depuration varied markedly between strains, with one strain becoming undetectable at lower doses.
Significant effects of dose and strain on depuration, but time did not significantly affect removal.

Abstract

Vibrio (V.) parahaemolyticus is a leading seafood-borne human pathogen frequently detected in shellfish. While accumulation and depuration dynamics have been extensively studied in oysters, comparable data for blue mussels ( Mytilus edulis ) are limited. This study investigated the accumulation and depuration of two V. parahaemolyticus strains (clinical and environmental) and virulence genotype ( tdh + vs. trh + ) under controlled closed laboratory conditions. For the accumulation trials, mussels were exposed to 10 4 to 10 7 CFU V. parahaemolyticus /mL for 48h. Depuration trials were conducted for 72h after 18h exposure to 10 5 or 10 7 CFU/mL. Accumulation in mussel tissue was significantly affected by dose (F= 23.24, p < 0.001) and exposure time (F= 9.39, p < 0.001), while no strain effect was detected (F= 1.01, p = 0.315). Tissue concentrations of approximately 3–4 log 10 MPN/g were already detected within five minutes after exposure. Comparable final tissue concentrations of approximately 4–5 log 10 MPN/g were observed for both strains after 48h. In contrast, depuration differed markedly between strains. The RIMD strain ( tdh + ) declined to below the detection limit (LOD) when exposed to 10 5 CFU/mL but remained detectable at 10 7 CFU/mL, while the VPILSH strain ( trh + ) remained detectable after 72 h of depuration at both exposure levels. Depuration in mussel tissue was significantly affected by strain (F= 82.67, p < 0.001) and dose (F= 110.18, p < 0.001), while time was not significant (F= 0.39, p = 0.81). These findings reveal dose- and time-dependent accumulation but strain-dependent depuration, highlighting enhanced persistence of the environmental VPILSH strain in blue mussels. • Dose- and time-dependent accumulation of tdh- or trh -positive V. parahaemolyticus • Static depuration was incomplete, strain- and time-independent • 72 h depuration was insufficient to eliminate V. parahaemolyticus • Water concentrations did not reliably predict pathogen persistence in mussel tissue

Accumulation and strain-dependent depuration of tdh- and trh-positive Vibrio parahaemolyticus in blue mussels (Mytilus edulis) under closed conditions

Key Points

Abstract

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