1. It’s the small things in life The perils and power of microbes

2. What is a microbiome? A microbiome includes all the microorganisms in a particular ecosystem. The term is sometimes used to describe the community of microorganisms in a particular place. Sometimes it is used to describe the total of the genetic material of the microorganisms in a particular ecosystem.

3. The human microbiome The human microbiome refers to all of the microorganisms that live in and on your body, including your gut and your skin. Human cells are outnumbered ten to one by microbes in our bodies. We are home to around 10 000 different species of microbe. You are carrying around with you about one hundred trillion bacteria that make up 1–3% of your body mass.

4. Types of microorganism The type of microorganisms in the human biome varies depending on factors including where they are found on your body, what you have been eating and what medicines you have taken.

5. Types of microorganism Actinobacteria e.g. Streptomyces spp., Bifidobacterium spp. Bacteroidetes e.g. Bacteroides spp. Cyanobacteria Firmicutes e.g. Clostridium spp., Bacillus spp. Fusobacteria Proteobacteria e.g. Escherichia spp., Helicobacter spp. oesophagus stomach (without H. pylori) stomach (with H. pylori) hair skin colon vagina nostril mouth

6. The chicken microbiome The chicken microbiome is the community of microorganisms living in and on a chicken. A healthy balance of microorganisms makes for a healthy chicken. Microorganisms found in the guts of chickens do not usually make chickens ill, but if some of those microbes get onto the meat during processing and then into the human gut, they can cause illness in people.

7. The soil microbiome The soil microbiome is the community of microorganisms that live in the soil. It is huge – scientists have found that virtually every soil sample they analyse contains around 30 000 species of microorganisms.

8. Finding new antibiotics Antibiotic resistance in bacteria means the time may come when we can no longer cure bacterial diseases with the antibiotics we have now. Scientists are searching for new antibiotics in many places, such as crocodile blood, fish slime, the deep sea abyss and soil.

9. Hope from the soil Some microbes in the soil microbiome make chemicals that destroy other microorganisms; maybe they can help us too. However, we have not found a way to culture 90% of the microorganisms that grow in soil in the laboratory, so we have a long way to go. In 2015, scientists discovered teixobactin – a completely new type of antibiotic from soil bacteria that cured MRSA and TB in mice.

10. Hope from humans Scientists have only recently started to agree that a healthy mixture of microorganisms in your body may be important for keeping your gut healthy, helping you to maintain a healthy body mass and protecting you against microorganisms that can cause disease. Scientists are beginning to think that the human microbiome may contain organisms that will make the antibiotics of the future.