Specialist lecture on probiotic bacteria: Rebecca Rogers

Specialist Lecture:  Can environmental stress affect the functional properties of probiotic bacteria?

On 30^th July 2014, I had to opportunity to attend a specialist lecture from Dr. Daniel Armund of London Metropolitan University, at the London International Youth Science Forum. In a world where multi-drug resistant strains of bacteria and the use of antibiotics are becoming more and more prevalent, Dr Daniel Amund’s recent doctoral thesis on the influences of stress on probiotic bacteria has an enormous application. Launching his presentation with the jaw-dropping fact that humans are more bacteria than human – we have 100 trillion bacterial cells in our microbiome, 10 times our ‘human’ cell amount – Dr Amund initiated the explanation of his doctoral research.

Having a balanced and diverse microbiome of bacteria in the body is essential for regulation of human health, mood and protection. The prime probiotic bacteria has high resistance to acidity, bile and antibiotics – the latter of which should not be determined by genetic information on transferable plasmids, lest pathogenic bacteria obtain and develop the same antibiotic resistance - and, most importantly, destroys invasive pathogenic bacteria. As the specific bacterial species present in the microbiome are dependent on a myriad of factors, such as age, diet and the use of antibiotics, the microbiome is unique to every individual.

Of this research, what intrigued Dr Amund was the impact of adverse conditions of the alimentary canal on probiotic bacteria must travel. To what extent can ingested probiotic bacteria of yoghurt benefit humans after enduring stress? During his experiment, Dr Amund focused on 5 separate strains of Bifidobacterium, which are quite common in the probiotic products like yoghurt, and recreated the harsh, stressful environment of the alimentary canal. He altered factors such as pH, bile concentration and NaCl concentration.

Through the analysis of his results, Dr Amund found that the most likely relationship between stress and functionality of probiotic bacteria, is positive. This is based on an increased ability of the bacterium to form a biofilm which increases the probiotic bacteria’s resistance.

There is an essential term here: “most likely”. This thesis represents a gap in the body of knowledge as identified by Dr Amund. Yet, what is astonishing is in providing a possible solution to this question, Dr Amund has unearthed an abundance of uncertainty regarding the influences on probiotic bacteria. Another example of this unending uncertainty is the how the Food Standards Agency, or FSA, has recently rejected long-established health claims, requiring new research to be conducted.

An analogy that I found particularly remarkable is that between humans and bacteria, if not all living organisms. Throughout a human’s lifespan, genes will activate and deactivate according to the specific environment. The gene, gtf01207 of bacteria, is predominantly expressed in an environment of osmotic stress. Similarly, we find as humans that “what does not kill us, makes us stronger”, and similarly bacteria were able to form greater resistance via their biofilms after a stress. Yet despite this, both humans and bacteria will still have an ideal set of environmental parameters in which they thrive. So, it is necessary to learn from bacteria and adopt a relatively stress-free life to be the best human you can be. This is an essential life lesson that I took from this awe-inspiring lecture. Thank you, Dr Amund!

Dr Amund spoke at the London International Youth Science Forum 2014. To find out more about 2015's LIYSF, visit the website here.

Rebecca Rogers, South Africa