iGEM Montpellier 2018 : A New Non-Hormonal Contraception


This year, and for the very first time, a Montpellier (France) iGEM team has been created, composed of nine passionate undergraduate students from different schools. iGEM is the world’s biggest competition of synthetic biology. They have decided to study the vaginal microbiome.


Microbiome. This word has been everywhere in the scientific community for the last decade. Although this is a very complex system, scientists are discovering new findings every day, and even if there are a lot of different microbiomes to study, one of the most represented is the gut microbiome. Did you know that another microbiome below is just as important and interesting than the gut microbiome for half of the population? The vaginal flora is part of every woman’s life, it is protecting every single one of them from a lot of inconveniences such as discomfort and even diseases. It is made from specific bacteria living together in balance to make the vagina a safe and healthy place. Unfortunately, this microbiome is sometimes damaged due to everyday life (for instance vaginal wash, bad hygiene or the membrane surfactant nonoxynol-9 (N-9) from vaginal contraceptive products). Once the balance is lost, the flora can be surrounded by pathogenic microorganisms. This can go from an itchy vagina to mycosis or increasing chances of having a sexually transmitted disease. Moreover, women have suffered from invasive and expensive methods for contraception, such as the pill and the IUDs (intrauterine devices). Based upon these facts, the Montpellier team wanted to tackle an iGEM project that would address those issues.


The team decided to focus on making a new kind of contraceptive using Lactobacillus jensenii, which is one of the most represented bacteria in the vaginal flora. This hormone-free contraception uses a designed Lactobacillus jensenii that has the ability to immobilize spermatozoa in the vagina. How does it really work? Their goal is to create bacteria capable of having a “light switch effect”. When a woman decides to turn it on, bacteria will have a spermicidal effect and will allow in situ contraception. Otherwise, bacteria will be in “off mode”, and spermatozoa will be able to pass. Several studies have demonstrated that Nisin - an antimicrobial peptide - has spermicidal activity. Nisin is a bacteriocin produced by Lactococcus lactis, which is nontoxic to humans. The idea is to introduce the gene that is coding for Nisin into Lactobacillus jensenii and then to apply a colony of these designed bacteria into the vagina for long-term contraception. When a woman wants to remove this contraceptive device, the team must find a way to stop the spermicidal effect of the bacteria.


Microbicide can allow a new way of contraception: safe and affordable, where women don’t have to negotiate with their partners.

Why is it crucial to find a new approach to contraception?

Hormonal contraception has a lot of side effects for women (such as weight gain or acne), a pill is easy to forget, and there is the environmental aspect of water contamination by hormones.

Moreover, it has been shown that it’s difficult for women to negotiate the use of condoms with their partners (which is the only method to prevent STD infections and another common method to avoid unwanted pregnancies). Microbicide can allow a new way of contraception: safe and affordable, where women don’t have to negotiate with their partners.


This project is generously supported by their university (Université de Montpellier), and the CBS research center (Center of Structural Biochemistry), which they are proud to represent on their visit to the USA. The team wants to take part in this science program by characterizing and sharing new parts of L. jensenii as well as to present their project to the scientific community.


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