Study OAS · 22 January 2025

Oyster Blood Proteins Enhance Antibiotic Effectiveness

Recent research by Southern Cross University has unveiled that proteins found in the blood, or hemolymph, of the Sydney rock oyster possess significant antibacterial properties and can enhance the efficacy of conventional antibiotics.

Key Findings:

• Antibacterial Properties: The hemolymph proteins were effective against pathogens responsible for respiratory infections, such as Streptococcus pneumoniae and Streptococcus pyogenes.
• Biofilm Disruption: These proteins can prevent the formation of biofilms—a protective layer formed by bacteria—and disrupt existing biofilms, making bacteria more susceptible to antibiotics.
• Synergistic Effect with Antibiotics: When combined with conventional antibiotics, the oyster proteins enhanced the drugs' effectiveness against bacteria like Staphylococcus aureus and Pseudomonas aeruginosa, which are known to infect immunocompromised individuals.
• Safety Profile: Importantly, the oyster hemolymph proteins were not toxic to human lung cells, suggesting potential for safe therapeutic applications.

Significance:

The discovery offers a promising avenue in the fight against antimicrobial resistance (AMR), a pressing global health concern where bacteria evolve to withstand existing antibiotics, leading to challenging infections and increased mortality.

Additional Information:

Sydney Rock Oyster

The Sydney Rock Oyster (Saccostrea glomerata) is a species of oyster native to Australia and New Zealand. It's a popular delicacy and an important part of Australia's aquaculture industry.

• Scientific Name: Saccostrea glomerata
• Common Names: Sydney Rock Oyster (Australia), New Zealand Rock Oyster or Auckland Oyster (New Zealand)
• Distribution: Found in estuaries and coastal waters along the eastern coast of Australia, from Queensland to Victoria. Also native to northern New Zealand, though not commercially farmed there anymore.

Physical Characteristics:

• Thick, smooth shell, typically greyish-white on the outside and smooth white inside.

• The shell can grow up to 8 cm in length.

• Has small teeth on the inner margin of the shell near the hinge.

• Habitat: Thrives in sheltered estuaries and bays, attached to rocks and other hard surfaces in the intertidal zone and up to 3 meters below the low water mark. They can tolerate a wide range of salinities.

Life Cycle:

• "Broadcast spawners": release eggs and sperm into the water for fertilization.

• Larvae are free-swimming for up to three weeks before settling on a suitable substrate.

• They change sex during their lifetime, starting as males and later becoming females.

• Aquaculture: Widely cultivated in Australia, particularly in New South Wales. They are known for their unique flavor and long shelf life.

• Flavor Profile: Distinctive rich, creamy, and sweet flavor with a lingering aftertaste. The flavor can vary depending on the estuary where they are grown ("merroir").

Significance:

• Important part of Australia's seafood industry.
• Ecologically important as filter feeders, helping to maintain water quality in estuaries.
• A culturally significant food source for Indigenous Australians.

Antimicrobial Resistance (AMR)

Antimicrobial resistance (AMR) is a critical global health threat. It occurs when microorganisms (bacteria, fungi, viruses, and parasites) evolve to resist the effects of drugs designed to kill them, such as antibiotics, antifungals, antivirals, and antiparasitics. This makes infections harder to treat and increases the risk of disease spread, severe illness, and death.

• Definition: The ability of microorganisms to survive and multiply in the presence of antimicrobial drugs that were originally effective against them.  

Causes:

• Overuse and misuse of antimicrobials: This is the primary driver of AMR. Unnecessary prescriptions, incorrect dosages, and use of antibiotics for viral infections contribute significantly.  
• Use of antimicrobials in agriculture and animal husbandry: The use of antibiotics in livestock for growth promotion and disease prevention also contributes to the development and spread of resistant microorganisms.  
• Poor infection prevention and control practices: Inadequate hygiene, sanitation, and infection control measures in healthcare settings facilitate the spread of resistant microorganisms.  
• Spread of resistant microorganisms between humans, animals, and the environment: Resistant microorganisms can spread through various pathways, including direct contact, contaminated food and water, and the environment.  

Consequences:

• Increased treatment failures: Infections become more difficult and sometimes impossible to treat.  
• Longer durations of illness: Patients stay sick for longer periods.  
• Higher healthcare costs: More expensive and prolonged treatments are required.  
• Increased mortality: Infections that were once easily treatable can become life-threatening.
• Threat to modern medicine: Many medical procedures, such as surgery, organ transplantation, and chemotherapy, rely on effective antimicrobials to prevent infections. AMR threatens the safety of these procedures.  

Examples of Resistant Microorganisms:

• Methicillin-resistant Staphylococcus aureus (MRSA)  
• Vancomycin-resistant Enterococci (VRE)  
• Carbapenem-resistant Enterobacteriaceae (CRE)  
• Multi-drug resistant tuberculosis (MDR-TB)