Biology of Spirochetes



Spirochetes are the causative agents of several important animal and human diseases such as syphilis, Lyme disease and Leptospirosis. The unit is composed of a research group on Leptospira and the National Reference Centers for Borrelia and Leptospira.

The main objective of the Unit is the study of virulence factors in pathogenic strains of Leptospira.


Mathieu Picardeau Lab

Our group has developed a number of tools for genetic manipulation of our model bacterium, the saprophyte L. biflexa in recent years. Since we were interested in iron homeostasis in Leptospira, we performed targeted and random mutagenesis in L. biflexa, then allowing the characterization of several genes encoding iron transporters. This project should also make it possible to evaluate the role of iron in the virulence of pathogenic Leptospira in the infected host.




We sequenced the complete genome of the saprophyte L. biflexa in collaboration with the Platform Genome Analysis of the Pasteur Institute and the Genoscope (Evry, France). The ease of genetic manipulation in L. biflexa provides us  with an ideal opportunity for studies of the biology of Leptospira. A comparative genomic analysis between saprophytes and pathogens should reveal clues on the life-styles of Leptospira in the environment and in the infected host providing an opportunity for understanding the transition of an environmental bacteria into an important human and animal pathogen.


The main objective of the National Reference Centers is to transmit the epidemiological traits of Leptospirosis and Lyme disease to Health authorities. We also have the duty to improve diagnostic techniques. For example, we developed a rapid and simple typing method based on the analysis of the polymorphism of variable-number tandem repeats (VNTR) loci in the genome of the pathogenic species of Leptospira. Finally, a surveillance of the incidence of tick contamination by Borrelia is conducted concurrently in different geographical areas in France.


This Unit, covering both fundamental questions and applied sciences in collaboration with the two NRCs, should help to improve our understanding of the biology of spirochetes which remains largely unknown.


Biology of Spirochetes
Institut Pasteur
28 rue du docteur Roux, 75724 Paris Cedex 15, France.
Tel: 33 (1) 45 68 83 37.
Fax: 33 (1) 40 61 30 01.