Antibiotic resistance in the Wadden Sea

When you get sick from a bacterial infection, you can treat it with antibiotics. These are drugs that can kill bacteria. If antibiotics are used too often, bacteria can become resistant to them, making them less effective against infections. Our veterinarian Ana Rubio Garcia tests rescued seals for bacteria that have become resistant to antibiotics. This research can tell us more about antibiotic resistance in the Wadden Sea.

Laatst geupdate op 16-01-2023
  • Zeehondenmoeder en pup
  • Medicatie voor zeehonden
  • Onderzoek naar antibioticaresistentie bij zeehonden

What is antibiotic resistance?

If people use antibiotics too often, the bacteria they are supposed to treat can become resistant. This means that the bacteria are no longer sensitive to the drug—they won’t be killed by it anymore. This is very problematic. If it keeps happening, the chance of healing a bacterial infection becomes smaller and smaller. New medicines would have to be developed to fight these bacteria. That is why it is important to only use antibiotics when necessary.

How does this end up in the Wadden Sea?

There is a chance that antibiotic-resistant bacteria end up in the Wadden Sea. When these bacteria leave our body, they get into the sewers through the water we use. From there, they can find their way into rivers and eventually the sea. For example, seals might come into contact with this type of bacteria and ingest them. By examining these seals, we can demonstrate that there are antibiotic-resistant bacteria in the Wadden Sea.

Onderzoek naar bacteriën bij zeehonden

Bacteria in seals

Ana wants to know if seals have bacteria in their bodies that are not sensitive to antibiotics. Her doctoral research (PhD) concerns all microscopic organisms that can occur in a seal, such as bacteria, viruses, and fungi. As a part of her research, Ana investigates whether antibiotic-resistant bacteria are common in seals.

We carry out this research on the seals that we have in rehabilitation. With each intake, we take a sample from the seal’s anus with a cotton swab. The cells in this sample are then grown in our laboratory. By multiplying cell samples in the lab, we can see which types of organisms there are.

Did you know...

We work together with several parties to monitor antibiotic resistance in the Wadden Sea. The research is supervised by the Faculty of Veterinary Medicine of Utrecht University (UU) and the Department of Medical Microbiology and Infection Prevention of the University Medical Centre Groningen (UMCG). Determining the type of bacteria and the presence of antibiotic resistance is done by the IZORE laboratory in Leeuwarden.

Results of the research

Ana's research shows various results. For example, seals have many of the same types of bacteria in their bodies as humans. She also found very few bacteria that were no longer sensitive to antibiotics. In other words: there are not a lot of antibiotic-resistant bacteria in seals. That is good news! For now, things seem to be going well with antibiotic resistance in the Wadden Sea.

Antibiotic treatment in seals

We also looked at what happens to a seal in rehabilitation if it needs antibiotics to treat an infection. It appears that there is no difference between the bacteria of seals that received the treatment and seals that didn’t. This means that the seals’ gut bacteria returned to normal after treatment. This is very striking, since the recovery of natural gut bacteria in humans can sometimes take months or years. This implies that the use of antibiotics in rehabilitated seals will have no effect on the Wadden Sea when they are released.

The seal as bio-indicator for antibiotic resistance

Seals are an important bio-indicator for antibiotic resistance in the Wadden Sea—they show us how things are going with their environment. By continuing this research, we can keep an eye on whether or not the situation changes.

Watch a mini-documentary below about how the centre monitors antibiotic resistance in seals:  

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