Dr Armpit to the rescue!

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Chris Callewaert received a Master’s degree in Bioengineering at Ghent University in 2010. In February this year he successfully finished his PhD about body odor, and more specifically, that of smelly armpits. He tries to solve this problem in a unique way: by using bacterial transplantations. We spoke with this ambitious young man.

Tell me about the goal of your PhD.
“The overall objective was to investigate everything around body odor and formulate solutions to counter it. As such, we characterized the microbiota involved in axillary body odor, investigated the psychological impact of it, studied the effect of the widely-used deodorants and antiperspirants on the armpit microbiome, analyzed the effect of textiles on body odor development and studied the bacterial exchange in laundry machines.  We investigated the possibility of bacterial transplants to improve one’s body odor,  developed an artificial sweat composition for high-throughput screening of compounds, and then developed nano-capsules for slow release of perfumes on the skin.”

What were the main findings?
“With the recent novel molecular analysis tools, we were able to characterize all bacterial species involved in the malodor development in the human armpit (Corynebacterium spp. were the most important ones) and clothes (Micrococcus spp. were the important ones here). Surprisingly, we also found bacterial species responsible for a good odor in the armpit. The use of deodorants and antiperspirants caused an increase in bacterial diversity. In the case of antiperspirants, it can also result in an increase in Corynebacterium spp., which could lead to more body odor development.  Antiperspirants work against hyperhidrosis (sweating a lot), but not against osmidrosis (smelling a lot), as the aluminum salts cannot reach the sweat glands where body odor originates from.

Additionally, polyester clothes were identified as a source of body odor. Micrococci were isolated, detected and selectively enriched on the polyester shirts and regarded partially responsible for the malodor generation. Laundering of the clothes resulted in a decrease in microbial counts, however, the same bacterial species were still present. Laundering resulted in a microbial selection of typical clothes and skin-related bacteria on the washed textiles. Malodor-causing microbiota can consequently be further distributed to other laundered clothes.

This research investigated the potential of an armpit bacterial transplantation to improve the axillary odor. The armpit bacterial transplantation seemed successful between family members. An induced dominance of Staphylococcus spp. was obtained, together with a decrease of Corynebacterium spp., with a subsequent improvement in axillary odor. The axillary therapy caused an odor improvement in both the short (one month – 90%) and longer term (three months or longer – 50% of the treated people).
The bottom line of this research is: we have long thought that killing off all bacteria was the solution against body odor. The answer all along might have been the protection of the ‘right’ bacteria.”

You gave a TED-talk at TEDxGhent, how did you get there?
“TEDxGhent organized a PhD contest to win a slot at the main TEDxGhent event in 2013. I participated in this and was able to win this competition.”

Your research became a media hype (The Washington Post, Terzake, Scheire en de Schepping, VRT news, RTBF news, Volkskrant). How did that happen?
“Ghent University launched our call for ‘smelly armpits’ on  social media, which was picked up by the Belgian television, newspaper and radio media. Many people were interested and came to our lab to investigate their armpits. As a form of feedback, the website DrArmpit.com was launched. It is also a place to share ideas and thoughts about smelly armpits. Body odor is a problem   worldwide; many people face it and worry about it. Our research indicated a high psychological impact. Today the website attracts over 8000 unique visitors each month, coming from all corners of the world. This website, together with the results from the published manuscripts, seemed very interesting for the international media.”

I will definitely continue on this path. DrArmpit has just begun.

In comparison to a general PhD student, you seem very aware of the importance of promoting your research. 
“An important part of research is communication. Most of the research is discussed through so-called A1 publications. This is still the way to go, but next to this there are many opportunities to communicate research openly with the public. After all, through my research, I want to inform and help people.”

Why did you choose smelly armpits as a research topic? 
“I chose this topic after a personal experience: my body odor changed from one day to the next. I dived into literature searching for the answer, but did not find it. Subsequently, I developed my own theory on how to solve it, in accordance with how I got it. Now I know this theory can work, as seen in several subjects, and as seen for myself: I eventually got rid of the body odor.

The final aim is to solve body odor. We will continue to work on it until we find a cure that works for everybody.”

Read more on www.drarmpit.com !