One hundred and twenty clinical and commensal Escherichia coli strains isolated in Switzerland from humans and from companion and farm animals were an

Irrespective of the root causes, it is now generally accepted that over a number of decades our planet has experienced a period of rapid warming (see Fig. 1). Even more concerning is the accelerating rate of change. This temperature increase is accompanied by a number of environmental changes, including: melting of the ice caps at the poles and glaciers in mountainous environments, sea level rise, warming of the oceans, increased frequency, intensity and duration of extreme weather events such as storms and floods in some parts of the planet or droughts in others. However, although less apparent to the naked eye, climate change has also profound effects on the microbial world, with direct or indirect impacts on humans, animals and plants. In fact, the total number of bacteria and archaea inhabiting Earth has been estimated at approximately 10³⁰ cells representing as many as 10¹² microbial species (Locey and Lennon 2016). Many of these microorganisms coexist in a state of equilibrium with each other and the environment. These microorganisms are essential for life on Earth as we know it, contributing to different vital cycles involving soil, water and air, such as the nitrogen, carbon and oxygen cycles (Madsen 2011). The proper functioning of these cycles is paramount for critical processes such as the production of organic matter and food for plants and animals as well as plankton in oceans, or the bioremediation capacity of soils. Needless to say, a disruption of these processes and ecological equilibria by global climate change is of significant concern. Thus, the impact of climate change on infectious diseases is also a matter of concern and subject to scientific enquiry. The aim of this thematic issue on climate change and microbiology is to highlight a few of these potential effects both in the environmental and infectious diseases domains.