Oyster blood kills lung infection bacteria, enhances antibiotics up to 32x – new discovery

Researchers from Southern Cross University in Australia find a protein in Sydney Rock Oyster hemolymph enhances antibiotics by disrupting bacteria’s protective biofilms.

From Southern Cross University 25/01/25 (first released 21/01/25)

While slurping oysters is not likely to replace popping a pill, they could help in the fight against superbugs.

A ground breaking find out of Southern Cross University has shown oysters might be able to help treat a growing worldwide public health problem: antibiotic-resistant bacteria.

In a study published today in PLOS ONE, the researchers demonstrate a protein in the blood, or hemolymph, of a Sydney Rock Oyster not only kills bacteria but increases the effectiveness of some conventional antibiotics against a range of clinically important bacteria.

Oysters have long been used in some traditional medicines, including to treat respiratory infection.

Further, the molluscs’ blood has previously been shown to have anti-viral activity.

This new research supports the potential use of natural products from oysters to treat bacterial infections.

Importantly, the oyster hemolymph proteins were not toxic to human lung cells, suggesting it should be possible to optimise a safe effective dose.

The study was supervised by Professor Kirsten Benkendorff from the Faculty of Science and Engineering.

“Most organisms have natural defence mechanisms to protect themselves against infection,” said Professor Benkendorff, reflecting on the origins of the study.

“Oysters are constantly filtering bacteria from the water, so they are a good place to look for potential antibiotics.”

This latest paper builds on a previous study where the research team identified a protein fraction in the hemolymph (blood) of the Sydney Rock Oyster that inhibits Streptococcus pneumoniae, a bacterium that causes respiratory infections like pneumonia and tonsilitis.

Bacteria that cause infections often escape from antibiotics and the immune system by forming biofilms to protect themselves.

Biofilms are communities of microorganisms that attach to surfaces, enclosed in a sticky, protective matrix.

The team’s discovery showed oyster hemolymph can kill bacterial pathogens in solution and in biofilms.

“The oyster hemolymph proteins were found to prevent biofilm formation and disrupt biofilms, so the bacteria remain available to antibiotic exposure at lower doses,” said Professor Benkendorff.

“The hemolymph contains a mixture of proteins with known antimicrobial properties.”

“These may act to directly kill the bacteria, as well as preventing them from attaching to the cell surface.”

Antibiotics have been the mainstay of treatment for bacterial infections since the early 20th century.

Unfortunately, bacteria have developed resistance to many conventional antibiotics due to overuse and misuse of these medications.

Antimicrobial resistance is predicted to cause 40 million deaths by 2050.

The need to discover new antibiotics is urgent.

While a new antibiotic drug developed from oyster blood is still some time away, the discovery brings hope for natural alternatives to treat infections.

“It provides great opportunities for collaboration between researchers, aquaculture and pharmaceutical industries,” said Professor Benkendorff.

“In the meantime, slurping oysters could help keep the respiratory bugs away.”

“Oysters contain zinc which boosts the immune system and they have really good polyunsaturated fatty acids and vitamins that also help modulate immunity.”