The Human Microbiome


The human microbiome consists of hundreds of trillions of microorganisms, outnumbering human cells by 10 to 1 with as many as 3 million bacterial genes to our approximately 20 thousand. While the microbiome has recently become an area of active research, its overall effects on human health remain largely unknown.

Bacteria from the human microbiome were among the first ones ever described by Antony van Leeuwenhoek, the “Father of Microbiology”. Despite that, until recently the studies of human-associated bacteria have been almost exclusively focused on pathogens. This has led to many advances in medicine and public health, including sterilization, antimicrobials, and antibiotics, however a vast number of other beneficial microorganisms that could critically impact human health have historically gone largely unstudied.

While pathogenic bacteria can be present in our microbiome, it also contains a vast number of commensal organisms that are either non-pathogenic or can only can become pathogenic under very specific conditions. In addition to not being pathogenic, these commensal bacteria are increasingly shown to have beneficial functions such vitamin K processing and the breakdown of complex carbohydrates, increasing their bioavailability.

If these natural commensal bacteria are eliminated by antibiotics or other means, an imbalance in the microbiome occurs. Clostridium difficile (C. diff), for example, causes life-threatening gut infections in people who have been taking antibiotics, killing 14,000 people per year in the US. When commensal bacteria are reintroduced by a simple transplant of gut flora from a healthy individual, the Clostridium infection is often resolved. This illustrates that maintaining a balanced microbiome safeguards human health.

AOBiome’s work focuses on re-introducing beneficial commensal bacteria such as Ammonia Oxidizing Bacteria to the human microbiome.