Superbugs have evolved to resist existing antimicrobial treatments, but new research into oysters may lead us to better antibiotics.
By Nigel Chimbetete
The survival of all life-forms on Earth depends on their ability to adapt, evolve, and thrive. Moreover, the mortality of a single life has primarily depended on their ability to protect themselves from bacteria, viruses, and pathogens, which now commonly go by the term “bugs.”
Industries like agriculture, human and animal health, and cosmetics rely on antimicrobials to eliminate harmful bugs. Unfortunately, this increased dependency has led to these bugs evolving to become resistant to current antimicrobial treatments. Hence, we are now living in the age of “superbugs.” Current research focuses on discovering compounds that decrease antimicrobial resistance and improving technologies currently utilized.
Thankfully, a team of researchers at Southern Cross University (SCU) discovered potential agents against superbugs hidden inside oysters.
A closer look into superbugs on the “half shell”
“Most organisms have natural defense mechanisms to protect themselves against infection. Oysters are constantly filtering bacteria from the water, so they are a good place to look for potential antibiotics,” said Professor Kirsten Benkendorff from SCU’s Faculty of Science and Engineering.
The study conducted and published by her team at SCU indicated the presence of antimicrobial proteins and peptides (AMPPs) in a semi-purified sample of oyster blood, from the Australian oyster Saccostrea glomerata, commonly called Sydney rock oyster. This work marks a significant step in investigating and extracting AMPPs from marine invertebrates. A recent review of AMPPs derived from aquatic invertebrates showed the phylum Mollusca, which oysters belong to, having the second highest recorded AMPPs.
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The study showed that the extract from Sydney rock oysters was effective against superbugs that cause respiratory infections, such as Streptococcus spp. The abundant type of AMPPs identified in the extract of the oysters was cystatins. These get their name from their function of inhibiting cysteine proteases and, as a result, play a critical role in strengthening immunity in various organisms, including humans, animals, and plants. Another finding within this work outlined the presence of other key proteins and peptides in the oyster blood extract, such as carbonic anhydrase, which could play a role in reducing the acidic conditions thereby increasing the activity of cystatins.
In the culinary world, oysters on the half-shell go very well with a combination of select sauces. However, Dr. Benkendorf and her team had other recipes in mind in their lab. “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.”
The study also showed a synergetic effect when combining the oyster blood extract with conventional antibiotics (ampicillin, gentamicin, trimethoprim, and ciprofloxacin), observing up to a 32-fold increase in efficacy against Streptococcus spp., Pseudomonas aeruginosa, Moraxella catarrhalis, Klebsiella pneumoniae, and Staphylococcus aureus.
“It provides great opportunities for collaboration between researchers, aquaculture, and pharmaceutical industries,” said Dr. Benkendorff.
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When a group of bioactive compounds is extracted to increase the concentration effect against targeted organisms, toxicity can be the barrier that stops all investigative progress despite the high success rates. Thankfully, toxicity assays in the SCU study indicated acceptable safety levels and that the compounds could be safely administered via inhalation, injection, and topical applications.
Since oysters are already farmed and harvested for consumption, the researchers point to the opportunity to sustainably optimize cultivation processes to further their research. For instance, oysters used for extractions may be smaller, misshaped oysters currently underpriced as “seconds.” In addition, researchers can harvest oysters during periods where water quality is acceptable for extracts but not high enough for food safety. They also foresee developing more efficient extraction methods and eventually a commercially viable chemical synthesis.
“In the meantime,” Dr. Benkendorff concluded, “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.”
Bon Appetit and Happy Shucking.
This study was published in the peer-reviewed journal PLoS ONE.
References
Aminov, R. I. (2010). A brief history of the antibiotic era: lessons learned and challenges for the future. Frontiers in Microbiology, 1, 134. https://doi.org/10.3389/fmicb.2010.00134
Rodrigues, T., Guardiola, F. A., Almeida, D., & Antunes, A. (2025). Aquatic invertebrate antimicrobial peptides in the fight against aquaculture pathogens. Microorganisms, 13(1), 156. https://doi.org/10.3390/microorganisms13010156
Southern Cross University. (2025, January 21). New discovery shows oyster blood proteins improve antibiotic effectiveness. https://www.scu.edu.au/news/2025/oyster-blood-proteins-antibiotic-effectiveness/
Summer, K., Guo, Q., Liu, L., Barkla, B., Giles, S., & Benkendorff, K. (2025). Antimicrobial proteins from oyster hemolymph improve the efficacy of conventional antibiotics. PLoS ONE, 20(1), e0312305. https://doi.org/10.1371/journal.pone.0312305
The information contained in this article is for informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.
Featured image provided by Southern Cross University.
About the Author
Nigel Chimbetete has a PhD in Food Science, specializing in Nutritional Biochemistry and Food Product Development. He is passionate about all topics surrounding food biochemistry and food sustainability. Outside of the lab, Nigel enjoys spending time with his family, traveling, and playing five-a-side soccer with his local community. Connect with him through @ChimbesHealth on X (formerly Twitter).
