Classifications Gut flora

candida albicans, dimorphic fungus grows yeast in gut

many species in gut have not been studied outside of hosts because cannot cultured. while there small number of core species of microbes shared individuals, populations of microbes can vary among different individuals. within individual, microbe populations stay constant on time, though alterations may occur changes in lifestyle, diet , age. human microbiome project has set out better describe microflora of human gut , other body locations.

the 4 dominant bacterial phyla in human gut firmicutes, bacteroidetes, actinobacteria, , proteobacteria. bacteria belong genera bacteroides, clostridium, faecalibacterium, eubacterium, ruminococcus, peptococcus, peptostreptococcus, , bifidobacterium. other genera, such escherichia , lactobacillus, present lesser extent. species genus bacteroides alone constitute 30% of bacteria in gut, suggesting genus important in functioning of host.

fungal genera have been detected in gut include candida, saccharomyces, aspergillus, penicillium, rhodotorula, trametes, pleospora, sclerotinia, bullera, , galactomyces, among others. rhodotorula found in individuals inflammatory bowel disease while candida found in individuals hepatitis b cirrhosis , chronic hepatitis b.

archaea constitute large class of gut flora important in metabolism of bacterial products of fermentation.

enterotype

an enterotype classification of living organisms based on bacteriological ecosystem in human gut microbiome not dictated age, gender, body weight, or national divisions. there indications long-term diet influences enterotype. 3 human enterotypes have been proposed, value has been questioned.