Issue: Metabolism, Health and Disease

07 May 2019 article

Welcome to the May edition of Microbiology Today, and up for investigation in this edition are microbial metabolism, health and disease. The ability of microbes to metabolise different substrates enables them to thrive in a vast diversity of niches, including various parts of the human host. The way microbes interact with metabolites influences how they affect the health of their host and can be linked to disease. This month our authors explore the fascinating range of ways in which these microbes and their metabolism can impact health.

To start us off on this theme, Kim Hardie reflects on how metabolism and the ability to utilise essential nutrients forms the basis of a healthy microbial cell. Revealing some of the many complex interactions linking metabolism and virulence, Kim demonstrates how these two factors are intertwined and can influence bacterial fitness within a population. Kim explains how these complex interactions can influence infection severity and concludes by providing some perspectives on how new technology could help further elucidate the intricate relationships between metabolism and virulence.

Next, Andrew Bell, Emmanuele Severi, Nathalie Juge and Gavin Thomas explore the various functions of sialic acid. Sialic acid is a metabolite of significant importance in bacterial–host interactions. Our authors outline the strategies microbes have devised for utilising sialic acid for different purposes. They reveal the ways in which both commensals and pathogens can use sialic acid, for example as food and for camouflage. They then Moving from bacteria to viruses, Sally Roberts and Joanna Parish consider how the development of organotypic raft cultures has improved our ability to study virus infection strategies. Explaining the basics of this technology, they describe how these rafts can be used to form fully differentiated epithelia. They explain how these organotypic rafts have been used to gain insights into the replication of herpesviruses, such as Epstein–Barr virus, and how they could be used in the future to support the testing of antivirals.

Staying with viruses, Matthew Moore discusses the difficulties in controlling norovirus, the outcome of infection (spoiler, it’s not good) and the complexities of in vitro cultivation of norovirus. Historically difficult to cultivate; it was only in 2014 that successful cultivation and replication of norovirus in human B cells was achieved, using enteric bacteria as a co-factor. Matthew reveals the advances in this field since 2014 and addresses the questions which will need to be answered to take this research forward.

We stay with the intestinal theme as Katharine Seton and Simon Carding walk us through the role of intestinal microbiota in health and disease. Starting with the microbiome in early life and highlighting the factors that impact on the health of our microbiome, they consider the impact of bacterial products on host health. With research increasingly making links between dysbiosis and disease, Katherine and Simon address the complexities of this area of research, the available evidence and the therapeutic potential in this area.

The Comment piece for this edition is written by Courtney Kousser, Farhana Alam and Rebecca Hall, and looks at the importance of fungi, their interactions within the human microbiome and the roles they can play in health. Explaining the range of interactions fungi can have with other microbes, they highlight how fungi can provide a route for bacterial dissemination, as well as impacting on the virulence of polymicrobial biofilms. The rising antimicrobial resistance of fungal pathogens and their ability to modulate the host immune system makes these microbes a fascinating part of the microbial world.

Rowena Jenkins

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Image: Faecal bacteria. Scanning electron micrograph of bacteria cultured from a sample of human faeces. Magnification: x6000 when printed 10 cm wide. Steve Gschmeissner/Science Photo Library.