This is the time of the year of increased physical activity when we pay special attention to certain parts of the body, including the armpit. As is usually the case, our microbiota is involved because the odor associated with sweating is produced by microbial activity. The main culprits are skin bacteria, both aerobes and anaerobes. The products that hit our nostrils are medium length fatty acids such as 3-hydroxyl-3-methyl-hexanoic acid (HMHA), a compound that is released from a precursor L-glutamine conjugate. Fujii and collaborators found that one of the most active bacteria producing HMHA is a species of Anaerococcus labeled A20. This strain could be isolated from the axilla of 12 healthy people.
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