Growing Bacteroides vulgatus in a strict oxygen free environment

Authors: Dr Paraic O Cuiv, Research Fellow in Gut Microbiology, UQ Diamantina Institute and Professor Mark Morrison, Chair, Microbial Biology and Metagenomics, UQ Diamantina Institute and Australian Infectious Diseases Research Centre.

Australia has amongst the highest rate of Inflammatory Bowel Disease (IBD) in the world but researchers at UQ Diamantina Institute are giving new hope to sufferers through their research into the microbiome and gut health in IBD. 

IBD is comprised of two predominant subtypes, Crohn’s disease and ulcerative colitis, which are characterised by episodic disabling inflammation of the gut. 

The disease has a lifelong impact and new therapeutic interventions are urgently needed to improve quality of life and restrain the healthcare costs associated with treatment.

It has long been known that IBD is underpinned by specific host genetic susceptibilities that are necessary but not sufficient for disease to develop. 

Interestingly, many of these genetic susceptibilities affect the ability of the host immune system to recognise and respond to microbes.

Consistent with this, it is now accepted that bacteria play a key role in the pathogenesis of IBD, although to date, no single causative bacterium has been identified. 

Instead, the microbes that naturally reside in the gastrointestinal tract, collectively termed the “gut microbiota”, play a central role in the pathogenesis of IBD. 

Thus new opportunities to better prevent or treat IBD could be developed if the causative microbes could be identified.

One of the most notable observations emerging from recent research is that despite the host genetic susceptibilities, the ability of gut bacteria to initiate and sustain an inflammatory response is restricted to a select number of gut bacteria. 

These bacteria are described as “pathobionts” in recognition of the fact that they are commonly found in the healthy gut environment but are also capable of causing disease under certain conditions.

Bacteroides vulgatus is one of the most abundant bacteria in the healthy human gut and a recognised pathobiont. 

In particular, it has been consistently identified as causing disease in animal models of IBD and has also been implicated in human disease.

The team’s research has focused on identifying the factors that enable B. vulgatus to colonise and persist in the IBD gut. Their analyses revealed that individual strains vary in their ability to initiate the host inflammatory response. 

These findings are consistent with the genomic analyses which revealed that B. vulgatus is characterised by significant interstrain variations and that specific genes that highly enriched in IBD subjects.

The research provids new insights into the role of B. vulgatus in the pathogenesis of IBD and will support the development of novel targeted therapeutic strategies.

Image: Dr Paraic O Cuiv growing Bacteroides vulgatus in a strict oxygen free environment.