Skin microbiome odor

Chris Callewaert is a researcher at the Ghent University Hospital who studies the relationship between the skin microbiome and skin disease. In this capacity he is doing research into the relationship between the skin microbiome in armpits and the development of body odor. This research has earned him the title “Dr Armpit”.

Smelly armpits or axillary osmidrosis is a condition in which an unpleasant odor emanates from the armpit region. This can significantly affect the quality of life of people. The armpit is home to an enormous amount of bacteria. Interestingly, however, compared to other parts of the body, the diversity of the bacteria in the armpit is rather low. In fact, some very dominant bacteria reside in the armpit, with staphylococci or corynebacteria being the most commonly found strains. The composition of the microbiome in the armpits determines whether a person will have body odor or not. In fact, while a dominance of staphylococci will result in a normal body odor, corynebacteria give rise to an unpleasant, sour or even fecal-like smell. Unfortunately, the composition of the skin microbiome is difficult to control. The classic solution to counter body odor therefore consists of deodorants that kill the bacteria in the armpit. After a couple of hours, however, bacteria can grow back and by the evening the bad odor often returns.

In an attempt to develop a more durable solution for body odor, Dr Callewaert looked into the potential of microbial transplantations. Surprisingly, transplanting the skin microbiome from people without body odor to the washed armpits of people with body odor led to spectacular results. Following this procedure, transplanted people did not suffer from bad body odor for up to a month. While these results were impressive, doing such a skin microbiome transplantation is not feasible on a routine basis. Therefore, Callewaert and colleagues isolated and cultured the ‘good odor’ bacteria and put them into a spray. With this spray it is possible to transplant armpits with favorable bacteria on a daily basis. Clinical trial results with this strategy proved to be very promising and a spin-off company has been set up to commercialize the spray.