“Bacterial action may also have some role to play in pheromone production, but not much is known about this at the time of writing. For example, the pheromone androstenol may oxidise (by bacterial action) to androstenone. Androstadienone can also be converted into androstenone. However, bacteria are responsible for causing the bad smells associated with body odor, and they do this by metabolising the chemicals (including the pheromones) in the oily apocrine secretions. A study on bacterial action on pheromones can be found here.”