Using bioreactors to study the effects of drugs on the human microbiota.

The study of complex microbial communities has become a major research focus as mounting evidence suggests the pivotal role microbial communities play in host health and disease. Microbial communities of the gastrointestinal tract, known as the gut microbiota, have been implicated in aiding the host with vitamin biosynthesis, regulation of host energy metabolism, immune system development, and resistance to pathogen invasion. Conversely, disruptions of the gut microbiota have been linked to host morbidity, including the development of inflammatory diseases, metabolic disorders, increased cardiovascular risk, and increased risk of infectious diseases. However, studying the gut microbiota in humans and animals is challenging, as many microorganisms are fastidious with unique nutritional or environmental requirements that are often not met using conventional culture techniques. Bioreactors provide a unique solution to overcome some of the limitations of conventional culture techniques. Bioreactors have been used to propagate and establish complex microbial communities in vitro by recapitulating the physiological conditions found in the GI tract. These systems further our understanding of microbial physiology and facilitate our understanding of the impact of medications and xenobiotics on microbial communities. Here, we review the versatility and breadth of bioreactor systems that are currently available and how they are being used to study faecal and defined microbial communities. Bioreactors provide a unique opportunity to study complex microbial interactions and perturbations in vitro in a controlled environment without confounding biotic and abiotic variables.