The Chesapeake Bay Bacteria You Didn’t Know About

 

Fig: These graph shows how V. parahaemolyticus levels in the Chesapeake Bay change with salinity, water clarity, and temperature across different seasons. Warmer and cloudier waters generally support more bacteria.

Have you ever wondered why eating raw or undercooked seafood sometimes makes people sick? One reason is a bacterium called Vibrio parahaemolyticus which is naturally occurring in brackish and marine waters and is one of the leading causes of seafood borne illnesses. A 2017 study led by Benjamin J.K. Davis explores what environmental conditions promote or limit this bacterium in the Chesapeake Bay's Water. They collected various water samples from various spots across four years. They tested these samples for things like temperature, saltiness (salinity), cloudiness (turbidity), and oxygen levels. Moreover, they checked if the versions that cause food poisoning were present. What they found was that V. parahaemolyticus thrives in warm, cloudy water, and it struggles to survive in saltier water. However, salt is not a big factor if the water is already warm or murky. Something interesting was that most water samples that contained this bacterium did not contain the genetic markers that cause virulence, meaning that the bacteria is not considered a harmful strain. Researchers noted, though, that figuring out how and when it becomes virulent is still an ongoing investigation. They also pointed out that shellfish can carry high levels of the disease-causing strains. This study is important because it shows how environmental conditions in the Chesapeake Bay influence the growth of V. parahaemolyticus. This can later be used to predict when seafood might be riskier to eat, helping protect both people who enjoy seafood and the industries that depend on it.

Article:

Davis BJK, Jacobs JM, Davis MF, Schwab KJ, DePaola A, Curriero FC. 2017. Environmental Determinants of Vibrio parahaemolyticus in the Chesapeake Bay. Applied and Environmental Microbiology. 83(21). doi:10.1128/aem.01147-17. https://doi.org/10.1128/aem.01147-17.