Plastic material and heating of sea water favor the virulence of pathogenic bacteria

by | Mar. 17, 2022

More than 20 million tons of plastic waste are dumped into the seas and oceans every year. This destructive scourge for marine biodiversity is also a proven risk for human health.

The study just published by the Monaco Scientific Centre identifies a new threat: the increase in sea water temperature favours the attachment of pathogenic bacteria to plastic surfaces and increases the risk of infection.

The study program conducted on Vibrio parahaemolyticus, responsible for severe food poisoning, shows that “under the effect of sea water warming, this marine bacterium goes from a state of dormancy to a state of activation…” explains Dr. Dorota Czerucka, research director in the ecosystem and immunity team at the Monaco Scientific Centre. “Under these conditions, the overexpression of virulence factors allows it to produce proteins involved in biofilm formation – its ability to colonize surfaces – and adhesins – attachment molecules, the first step in adhering to a cell in order to infect it.”


This study conducted at 21° (average Mediterranean temperature), 27° (average tropical temperature), 31° (IPCC forecast for 2050) also shows that under these same conditions, Vibrio parahaemolyticus strongly expresses hemolysis, a toxin that attacks the bloodstream by targeting red blood cells.

In the oceans, bacteria live mostly associated with sediments, plankton and plastics. The conjunction between the presence of plastic and the increase in temperature can transform plastics into “ecological niches”, likely to participate in the dissemination of these pathogens or to create infectious outbreaks: either by ingestion of filter-feeding organisms such as mussels contaminated by microplastics; or by direct contact in the sea water.

This mechanism observed for Vibrio parahaemolyticus can be found in other bacteria such as Vibrio vulnificus responsible for serious skin infections, potentially fatal.

The study was made possible by the Monaco government, Friends of the Scientific Centre, and Lady Monika Bacardi. Read the full study just published in Frontiers in Microbiology here :