Final answer:
The gut microbiome is primarily composed of the phyla Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, and the CFB group, which include significant genera such as Bacteroides, Clostridium, and Bifidobacterium among others.
Step-by-step explanation:
The human gut microbiome is composed of various microorganisms, including bacteria from different phyla that play a crucial role in health and disease. Five phyla that predominantly compose the gut microbiome are:
- Proteobacteria: This is a major phylum of gram-negative bacteria, including many known to be part of the normal human microbiota as well as some pathogens. The Proteobacteria are diverse, containing classes like Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, and Epsilonproteobacteria.
- Bacteroidetes: This phylum includes genera such as Bacteroides and Prevotella, which are important in the gut microbiome. Bacteroides, in particular, can constitute up to 30% of the gut microbiome.
- Firmicutes: This phylum includes the genera Clostridium, Ruminococcus, and others. Members of Clostridium are especially noted for their presence in the gut.
- Actinobacteria: This group includes the genus Bifidobacterium, known for its beneficial effects in the human gut such as the production of important vitamins.
- CFB Group: This includes the genera Cytophaga, Fusobacterium, and Bacteroides. They share similarities in DNA nucleotide sequences and are known for their rod-shaped, anaerobic characteristics.
Understanding these phyla provides insight into the complexity and significance of the microbiome in human health.