Bacillota can make up between 11% to 95% of the
human gut microbiome. The phylum Bacillota as part of the
gut microbiota has been shown to be involved in energy resorption, and potentially related to the development of
diabetes and
obesity. In multiple studies a higher abundance of Bacillota has been found in obese individuals than in lean controls. A higher relative abundance of Bacillota was seen in mice fed a western diet (high fat/high sugar) than in mice fed a standard low fat/ high polysaccharide diet. Specifically, within obese mice, the class
Mollicutes (within the Bacillota phylum) was the most common. When the microbiota of obese mice with this higher Bacillota abundance was transplanted into the guts of germ-free mice, the germ-free mice gained more fat than those transplanted with the microbiota of lean mice with lower Bacillota abundance. The presence of
Christensenella (Bacillota, in class Clostridia), isolated from human
faeces, has been found to correlate with lower
body mass index.
Faecalibacterium prausnitzii (F. prausnitzii) is a member of the Bacillota phylum that may have anti-inflammatory effects in humans. This species is associated with reduced low-grade inflammation in obesity. Additionally, patients with inflammatory bowel disease tend to have lower levels of
F. prausnitzii. It was recently mentioned that BilR (Bilirubin Reductase) is a gut microbial enzyme that reduces bilirubin to urobilinogen, emphasizing the role of the gut microbiome in the recycling of heme
Pathogenicity Several Bacillota species are common human pathogens. Examples include
Bacillus anthracis, Clostridioides difficile, and
Clostridium botulinum. Others, such as
Staphylococcus aureus and
Enterococcus faecalis, are opportunistic pathogens that cause illness in a minority of their hosts. Antibiotic resistance is an increasingly common problem with these infections.
Methicillin-resistant S. aureus (MRSA) is estimated to cause 100,000 deaths per year. == See also ==