Chapter 23
Defensive Microbiomes: A Widespread
Phenomenon in Nature
Sarah Worsley
Abstract Microbes, such as bacteria and fungi, produce antibiotic compounds
during competition with other species for resources such as space and nutrients.
Such compounds have underpinned much of modern medicine as, in their purified
form, they are widely prescribed by humans as antibiotics to cure bacterial and
fungal infections. However, numerous other organisms have been using the antimicrobial products of microbes to protect themselves against disease for millennia,
with many eukaryotic species forming close mutualistic interactions with defensive
microbes which live on or within their host species. In addition to producing
antibiotics, these microbes can inhibit infection by stimulating their host’s immune
system and by competing with, and thus excluding, pathogenic organisms. Developing an understanding of how interactions between hosts and protective microbes
arise and are effectively maintained over time, despite the evolution of pathogenic
resistance, could inform our own use of antibiotics as well as novel therapies. This
essay will discuss the prevalence of defensive microbiomes in nature and how their
assembly may inform future strategies to protect against disease.
23.1 Microbes Underpinning Modern Medicine
Humans have been widely using antibiotics to cure diseases caused by bacterial and
fungal agents since the late nineteenth century. Almost all of the earliest antibiotics,
and many of those used today, are the purified natural products of microbes which
have been isolated from environmental samples, such as soil (Gould 2016; Hopwood
2007). In natural systems, microorganisms produce these antibiotic compounds to
kill or inhibit the growth of other microbial species during competition for resources
such as nutrients or space.
Even before it was known that microbes were the source of many antimicrobial
compounds, ancient civilisations are thought to have used their products to prevent
S. Worsley (*)
University of East Anglia, Norfolk, UK
e-mail: s.worsley@uea.ac.uk
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_23
497
Defensive Microbiomes: A Widespread
Phenomenon in Nature
Sarah Worsley
Abstract Microbes, such as bacteria and fungi, produce antibiotic compounds
during competition with other species for resources such as space and nutrients.
Such compounds have underpinned much of modern medicine as, in their purified
form, they are widely prescribed by humans as antibiotics to cure bacterial and
fungal infections. However, numerous other organisms have been using the antimicrobial products of microbes to protect themselves against disease for millennia,
with many eukaryotic species forming close mutualistic interactions with defensive
microbes which live on or within their host species. In addition to producing
antibiotics, these microbes can inhibit infection by stimulating their host’s immune
system and by competing with, and thus excluding, pathogenic organisms. Developing an understanding of how interactions between hosts and protective microbes
arise and are effectively maintained over time, despite the evolution of pathogenic
resistance, could inform our own use of antibiotics as well as novel therapies. This
essay will discuss the prevalence of defensive microbiomes in nature and how their
assembly may inform future strategies to protect against disease.
23.1 Microbes Underpinning Modern Medicine
Humans have been widely using antibiotics to cure diseases caused by bacterial and
fungal agents since the late nineteenth century. Almost all of the earliest antibiotics,
and many of those used today, are the purified natural products of microbes which
have been isolated from environmental samples, such as soil (Gould 2016; Hopwood
2007). In natural systems, microorganisms produce these antibiotic compounds to
kill or inhibit the growth of other microbial species during competition for resources
such as nutrients or space.
Even before it was known that microbes were the source of many antimicrobial
compounds, ancient civilisations are thought to have used their products to prevent
S. Worsley (*)
University of East Anglia, Norfolk, UK
e-mail: s.worsley@uea.ac.uk
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_23
497