Is the Ocean our Toilet?: E. Coli threatening Australian Sea Lions with Mariel Fulham
BY FARRAH LEONE
I first came in contact with Mariel Fulham through my piece called “Fire Retardant Fur Seals: A Team Interview”. She was involved in a project that detected the level of fire retardant chemicals in three pinniped species of southern Australia. One of these species, the Australian Sea Lion (N. cinerea) is endangered AND endemic with only ~6,500 breeding adults remaining. Currently, the species faces PFA’s threatening the immune system development in pups, hookworms, tuberculosis, and, according to Mariel, human strands of E. Coli.
Fulham’s speciality is studying the microbiome (the “ecosystem” of tiny organisms living inside of something else to help it survive) of pinnipeds (seals, sea lions, and walruses). She conducted her field research simultaneously with the study mentioned above.
Mariel Fulham and her new friend! (Photo Credit: Mariel Fulham)
What came first, your love of seals or your love of microbiology?
My love for animals definitely lead to my love of seals first. I was lucky enough to do my honours project with Dr Rachael Gray looking at Escherichia coli in Australian sea lion pups. From that project I found my interest for research and studying bacteria, and have been fortunate enough to continue that project and turn it into a PhD to now look at bacteria in Australian sea lion, Australian fur seal and long-nosed fur seal pups.
2. Why did you focus on younger seals as opposed to adults?
We originally collected adult samples opportunistically from each colony that we were sampling pups. These samples were from unknown adults and the isolation of E. coli was much lower from adult samples which made the decision to focus on pups a lot easier. The focus of our research group is on pinniped pup health – we collect samples from pups that allow us to investigate and monitor their health. Looking at E. coli in pups that we also have health data for means that we can look at the presence of E. coli in relation to pup health as well.
3. How many days do you approximate that E. coli (or at least the human strands) can live outside of the host?
It depends on the environment that the bacteria is contained in and the environmental conditions. If the bacteria is in faecal (poo) samples, it is more protected can last longer than if it was outside in the environment by itself. If environmental conditions are favourable for the survival of bacteria it could survive for 3-4 days outside a host.
4. Do you have any ideas of areas that might be contributing more E. coli pollution than the rest?
Not at this stage. Looking at sources of the E. coli was outside the scope of our study. Hopefully future investigations will give us an opportunity to find out more about the E. coli strains we identified and trace them back to a source.
5. Were any of your results surprising to you?
We were surprised that there was no difference in the E. coli phylotypes across the three species and the eight breeding colonies we looked at. We initially thought that the human-associated B2 and D phylotypes would be more prevalent in colonies that are located closer to human populations and have more interactions with humans (Seal Bay on Kangaroo Island and Seal Rocks off Phillip Island are both big tourist attractions). What we found was that the location of the colony didn’t make a difference to the distribution of E. coli phylotypes. We were surprised to see such widespread distribution of the human-associated B2 phylotype – the pups we are sampling haven’t yet left their breeding colony so the environments they are exposed to are very limited and they are not yet foraging for themselves. This suggests that the bacteria is either transferred maternally (from their mothers), or the breeding colonies are contaminated with the bacteria.
6. Have you noticed any of the negative side effects of B2 and D E. coli in the pups?
No, we haven’t, which is great. The B2 phylotype is associated with bacteria that causes disease in humans and avian species, especially when the hosts are immunocompromised. We hope that finding out a bit more information about the actual bacteria we are finding (such as the specific strain of E. coli) can help us understand whether the E. coli in the pups could potentially cause disease in the future.
7. What suggestions do you have for the individual to reduce their E. coli or impact in general on the species?
At this stage it is really about investigating the source of the E. coli. We have done the first step in actually identifying it, but now we need to know where it is actually coming from in order to understand how to limit further spread and environmental contamination.
8. Are there any resources that people can be directed to learn more,
sign petitions, volunteer, etc?
Our research group at the University of Sydney in the Sydney School of Veterinary Science will continue to publish new data in similar areas! Hopefully bringing more awareness to the issues that are being faced by the pups will provide a platform for more resources in the future.