Bacterial Diversity in the Human Gut

Abstract

Publisher Summary The human digestive tract is colonized by highly complex microbial ecosystem containing vast numbers of bacteria that could be assigned to several hundred bacterial species. Bacterial colonization of the gut is affected by a wide variety of host, microbiological, environmental and dietary factors, as indicated in the chapter. Until recently, our knowledge of bacterial diversity in the large intestine was derived by using classical viable counting techniques. However, the advent of molecular methods of analysis has led to renewed interest in the structure and composition of the gut ecosystem. The advantages of culturing techniques are that they are relatively inexpensive, widely available, and quantitative. On the other hand molecular techniques are rapid and have the potential for high throughput analysis. Biological samples can be frozen, while DNA is easily transported among laboratories. They also allow so-called unculturable species to be detected. The disadvantages of these technologies are that they tend to be expensive, while some bacteria are more susceptible to lysis than others and can therefore be detected more easily.