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Justin's Story

This page explores Dr Justin O’Sullivan’s role in the Gut Bugs team and the work he has contributed to the trial.

Justin O'Sullivan


Dr Justin O’Sullivan is Associate Director for Research at the Liggins Institute, the University of Auckland. He is Co-Investigator on the Gut Bugs trial and developed Gut Bugs along with Principal Investigator, Professor Wayne Cutfield.


Justin is a microbiologist. He completed his PhD in molecular microbiology at the University of Otago and has held postdoctoral positions at the University of Kent and the University of Oxford in England. Dr O’Sullivan’s research interests include genome biology and epigenetics - understanding more about the complex relationships between genotype (what a cell’s DNA codes for) and phenotype (the physical expression or what is actually seen). He uses and develops methods and technologies from molecular biology, bioinformatics and computational biology.


Nature of Science Ideas

  • Science is a collaborative process and scientists often work in teams
  • Science is about asking questions and testing new ideas



Justin’s role in Gut Bugs is to design and develop trial procedures and to lead teams of researchers. He explains: “Projects like Gut Bugs are huge. They run for multiple years across multiple people. People join the trial to contribute to specific areas or needs. So it’s a really interesting thing. A lot of people are doing PhDs (like Thilini Jayasinghe and Karen Leong), and we have to ensure that each PhD student is able to have a fixed piece of work that is theirs, that they have done and published. We have structured the trial in a way to ensure that people are getting significant pieces of work that they can use to say: ‘This is my contribution’.”

This is possible because, in a trial like Gut Bugs, it’s not just about the experimental design. Different analyses on different aspects mean that different questions will emerge, which are all very important, and which contribute to the overall knowledge about the process. Will the bacteria engraft into a person (become successfully incorporated into the body)? Will the engraftment cause a change? Is it the bacteria that are responsible for any change seen, or is it another component of the microbiome (for example, the mycological or fungal component)?


As leaders of the Gut Bugs trial, Prof. Cutfield and Dr O’Sullivan also have different expertise and different roles. Justin (as the microbiologist) is specifically responsible for the microbiome analysis and for the development of processes for capsule preparation, while Prof. Cutfield is responsible for the clinical component.


Nature of Science Ideas

  • Science builds on what is already known
  • Science is about asking questions and testing new ideas, but contemporary social issues and environments inform the questions asked


Before any new ideas or medical treatments can be used to help people, there must be a careful scientific process of trial and development. This includes an ethics process.


The original idea for Gut Bugs evolved out of discussions between Justin and Wayne, who had been working together for many years. Justin reiterates that although Gut Bugs is “pretty radical”, the original idea of faecal transfer is not unique. Chinese in the fourth century used faecal transfers to restore bacterial balance in the colon and successfully treat Clostridium difficileinfection. The idea for Gut Bugs occurred within the current context of rising rates of obesity and trying to understand ways to treat this current epidemic. 


Importantly, there was enough evidence to convince the ethics committees and others (for example, the project funders) that the idea was viable. The trial was designed with strict controls around data monitoring and safety, such as looking for pathogens and potential side effects. The Ethics Board was confident that if anything was to happen, the issue would be identified quickly and that systems were in place to fix it. 


Justin mentions that, so far, there have been no treatment-associated difficulties. He says, “it’s actually a phenomenally safe thing to do - it’s really amazing - as long as you are doing the right things.” However, he cautions that there remains a very remote possibility that a huge complication (which the team are, as yet, unaware of) could show up long-term. 


Nature of Science Ideas

  • Science is a collaborative process and scientists often work in teams where different people hold different skills sets
  • You don’t need to know it all… Science is about being able to understand and talk with others about their work


Safety is the key consideration in everything that the Gut Bugs team attempts - they are extremely careful to ensure that what they are doing will not negatively impact people. If the pilot had shown any negative consequences, it would have been stopped immediately.


Nature of Science Ideas

  • Science is a collaborative process and scientists often work in teams where different people hold different skills sets
  • You don’t need to know it all… Science is about being able to understand and talk with others about their work


Understanding the complexity of a trial such as this and comprehending how different skill sets merge to manage this complexity is important, according to Justin. Due to the breadth of expertise required, Gut Bugs is a team effort - and not something that just one individual can do. 


He describes the trial as “a true collaboration”, requiring statistical expertise, medical expertise and microbiology expertise. With teams working together, “what comes out is way more complex than what went in.” Justin acknowledges that, by international standards, the Gut Bugs team is not particularly big and yet, it is still quite large. 



It is also important in a trial such as this to be able to talk to other researchers on the team. It’s about being able to think and converse across different disciplines. It’s about communicating with individuals and understanding enough about their knowledge to be able to integrate it with other knowledge or findings being produced.


Dr O’Sullivan is excited by the results of the Gut Bugs pilot. Findings from this small trial show clear evidence that the gut microbiome shifted. This means that there was engraftment and that there is augmentation (increase in gut bacteria diversity) - “that’s fantastic”, he says. He is similarly excited by evidence that recipients’ blood work changed - a significant difference such as this, and noted with such a small number of participants, is evidence that “things are changing.” 


Nature of Science Idea

  • Science is innovative, exciting, and breaks new ground