Field survey at Hempstead Harbor.

<p>Field survey at Hempstead Harbor. A) Concentrations of total (blue) and pathogenic (red) <i>V</i>. <i>parahaemolyticus</i>. B) Percent of total <i>V</i>. <i>parahaemolyticus</i> identified as pathogenic. C) Concentrations of enterococci (solid) and fecal coliforms (dashed). Error bars represent 95% confidence intervals.</p

Field survey at Oyster Bay Harbor.

<p>Field survey at Oyster Bay Harbor. A) Concentrations of total (blue) and pathogenic (red) <i>V</i>. <i>parahaemolyticus</i>. B) Percent of total <i>V</i>. <i>parahaemolyticus</i> identified as pathogenic. C) Concentrations of enterococci (solid) and fecal coliforms (dashed). Error bars represent 95% confidence intervals.</p

Total <i>Vibrio parahaemolyticus</i> concentrations in response to dissolved organic matter and water temperature.

<p>A) Concentrations of total <i>V</i>. <i>parahaemolyticus</i> with and without dissolved organic matter additions; B) Proportion of samples containing pathogenic <i>V</i>. <i>parahaemolyticus</i> with and without dissolved organic matter additions; C) Concentrations of total <i>V</i>. <i>parahaemolyticus</i> with and without a water temperature increase. Error bars represent 95% confidence intervals. Significant differences (<i>p</i><0.05) are indicated with an asterisk.</p

Primer sequences used in the MPN PCR assay.

<p>Primer sequences used in the MPN PCR assay.</p

Logistic regression model.

<p>Logistic regression model.</p

Field survey at Cold Spring Harbor.

<p>Field survey at Cold Spring Harbor. A) Concentrations of total (blue) and pathogenic (red) <i>V</i>. <i>parahaemolyticus</i>. B) Percent of total <i>V</i>. <i>parahaemolyticus</i> identified as pathogenic. C) Concentrations of enterococci (solid) and fecal coliforms (dashed). Error bars represent 95% confidence intervals.</p

The ability of algal organic matter and surface runoff to promote the abundance of pathogenic and non-pathogenic strains of <i>Vibrio parahaemolyticus</i> in Long Island Sound, USA

<div><p>Food safety is a major concern in the shellfish industry, as severe illness can result from consuming shellfish that have accumulated waterborne pathogens. Shellfish harvesting areas are typically monitored for indicator bacteria such as fecal coliforms that serve as proxies for enteric pathogens although these indicators have shown little relation to some naturally occurring pathogenic bacteria such as <i>Vibrio parahaemolyticus</i>. To examine the dynamics and ecology of pathogenic and non-pathogenic strains of <i>V</i>. <i>parahaemolyticus</i> and address the relevance of indicator bacteria in predicting <i>V</i>. <i>parahaemolyticus</i> concentrations, field surveys and experiments were carried out in western Long Island Sound, NY, USA, a region that has experienced recent outbreaks of shellfish contaminated with <i>V</i>. <i>parahaemolyticus</i>. Pathogenic and non-pathogenic strains were quantified via PCR detection of marker genes and most probable number techniques. Field survey data showed little correspondence between fecal coliforms and <i>V</i>. <i>parahaemolyticus</i>, but significant correlations between <i>V</i>. <i>parahaemolyticus</i> and an alternative indicator, enterococci, and between <i>V</i>. <i>parahaemolyticus</i> and short-term (48 h) rainfall were observed. Experiments demonstrated that enrichment of seawater with phytoplankton-derived dissolved organic matter significantly increased the concentration of total <i>V</i>. <i>parahaemolyticus</i> and the presence pathogenic <i>V</i>. <i>parahaemolyticus</i>, but higher temperatures did not. Collectively, these study results suggest that fecal coliforms may fail to account for the full suite of important shellfish pathogens but that enterococci could provide a potential alternative or supplement to shellfish sanitation monitoring. Given the ability of algal-derived dissolved organic matter to promote the growth of pathogenic <i>V</i>. <i>parahaemolyticus</i>, restricting nutrient inputs into coastal water bodies that promote algal blooms may indirectly decrease the proliferation of <i>V</i>. <i>parahaemolyticus</i> and protect public health.</p></div

Field survey at Northport Harbor.

<p>Field survey at Northport Harbor. A) Concentrations of total (blue) and pathogenic (red) <i>V</i>. <i>parahaemolyticus</i>. B) Percent of total <i>V</i>. <i>parahaemolyticus</i> identified as pathogenic. C) Concentrations of enterococci (solid) and fecal coliforms (dashed). Error bars represent 95% confidence intervals.</p

Field survey spearman rank correlations.

<p>Field survey spearman rank correlations.</p