Microbiology Editor's Choice: understanding a mycobacterial thermophile

Posted on June 1, 2020   by Microbiology Society

Each month, a manuscript published in our flagship journal Microbiology  is chosen by a member of the Editorial Board. This month, the paper is titled 'A genuine mycobacterial thermophile: Mycobacterium hassiacum growth, survival and GpgS stability at near-pasteurization temperatures' and it was chosen by Dr Jen Cavet. 

Like many other nontuberculous mycobacteria (NTM), Mycobacterium hassiacum is regularly detected in water supply systems and associated, although rarely, with opportunistic human infections. Here, the authors show that M. hassiacum is the most thermophilic NTM known to date, growing optimally at 50-65°C, and remaining viable at near-pasteurization temperatures.
The high resilience of M. hassiacum to heat treatment, which is an antimicrobial strategy commonly used in food and drink industries as well as water distribution systems, raises the potential use of M. hassiacum as an indicator of mycobacterial control, particularly of other NTM that are more commonly associated with human disease. Moreover, due to its thermo-tolerance, M. hassiacum represents a potential source of thermostable and easily tractable mycobacterial proteins, thereby offering a much needed aid for anti-mycobacterial drug discovery.

A genuine mycobacterial thermophile: Mycobacterium hassiacum growth, survival and GpgS stability at near-pasteurization temperatures

Some environmental nontuberculous mycobacteria (NTM) are opportunistic pathogens and are commonly detected in water distribution systems. A few NTMs are known to cause chronic lung infections and are resistant to multiple antibiotics. NTM infections are on the rise, especially in the chronically ill and in the elderly.

This work reveals the survival of a model NTM at near-pasteurization temperatures and the stability of one enzyme likely involved in its resistance to thermal stress. The persistence of NTMs in drinking water and showerhead aerosols, associated with their high resistance to heat and to other disinfection strategies, calls for the implementation of measures to reduce human exposure to these potential pathogens, for which effective therapeutics are still lacking.

We spoke with corresponding author, Dr Nuno Empadinhas, to find out more: 

What is your institution and how long have you been there?

I am Principal Investigator at the CNC-Center for Neuroscience and Cell Biology, part of the University of Coimbra in Portugal. I was hired as an Assistant Researcher 12 years ago.

What is your research area? 

Molecular microbiology, specifically mycobacterial biology.

What inspired you to research this topic?

Diseases caused by mycobacteria, such as leprosy and tuberculosis, are the oldest known to civilization. Tuberculosis has killed over 1 billion people in the past 200 years and, despite more than a century of research, it remains the leading cause of infectious death in the 21st Century. Mycobacteria rely on phenomenal strategies to cope with adversity. Although the subject of my PhD thesis was the adaptation of extremophiles to stress conditions, I also consider mycobacterial physiology extreme in its own way, and them as “poly-extremophiles”.

What is the most rewarding part of your research?

Novelty. Biodiversity. Cracking genetic and biochemical puzzles. To be the first in the world to know what an enzyme does and how it does it. To be allowed to lean on the “shoulders of giants”.

What would you be doing if you weren't a scientist?

I would definitely be a farmer. Maybe I will be in my 'golden years'.

Visit our journals platform to access the full paper. Editor’s Choice articles published in Microbiology are free to read.