27 mars 2014: Prof. Didier Raoult

Thursday, March 27th 2014, 12h30

Unité de recherche sur les maladies infectieuses tropicales (URMITE), Université Aix-Marseille


"Obesity and gut microbiota manipulation"

The manipulation of the gut microbiota is associated with weight gain, which has been used in the farm animals, as growth promotors, for more than 50 years. The antibiotics were very much used in farm animals. In Europe, their use is not authorized any more since 2002 whereas it is it always in the United States. Probiotics have been used as growth promotors, and are regulated, for 40 years in the farm industry in Europe. Most antibiotics are secreted by Actinomyces used like probiotics, to promote animal growth. The tetracycline was discovered in a probiotic. There are a specificity of the gut microbiota of the obese patients and a specificity of the microbiota of the very thin patients (anorexia or malnutrition). A literature analysis carried out in farm industry, in experimental models and humans, shows that some probiotics, in particular Lactobacillus, can be associated with a significant weight gain (in the birds, the pigs, the mice and humans) while others seem to have a protective effect against obesity. The effectiveness in weight gain is dependent on species and strains. In addition, the antibiotics prescribed in childhood, or for long periods (for example in the treatment of Helicobacter pylori or for endocarditis) are likely to cause very significant weight gain. The gut microbiota depends on nutrition and of the weight of the peoples and the manipulation of this microbiota can involve a considerable weight gain. For this reasons, antibiotics became recommended in the treatment of the severe denutritions.

Didier Raoult, born in 1952 in Dakar, Senegal, was trained in Medecine in Marseille, France (1972-78), were he specialised in internal medecine (1984) then in Infectious Diseases and Tropical Medicine (1985). Because the laboratory diagnostic became a major goal for him, he followed courses in microbiology and received a national diploma in Bacteriology, Virology (1981) and Parasitology (1982) and followed a course in Bacteriology at the Pasteur Institute in Paris, France (1984). He was trained in epidemiology by a continuous education program at the CDC, Atlanta, USA in Principles of Epidemiology (1983) and Infectious Diseases Control (1984). He parallely obtained a PhD in Microbiology in Montpellier, France (1985). He became Assistant Professor at Marseille School of Medicine in 1984, associate Professor in 1986 and full Professor in 1989. He is currently running a clinical microbiology laboratory for 2500 beds of University Hospitals, he is a consultant of infectious diseases for 2 half days/week. - As for administrative responsibilities, he was the President of the Scientific Committee of Marseille School of Medicine and University Hospital (1989-1994), then he became,the President of the Université de la Méditerranée in Marseille (Medicine, Science, Pharmacy, Economics, Sports, 20.000 students) (1994-1999). - As for scientific responsibilities, he is member of the ASM, IDSA, ESCMID, he did create the European Study Group of Rickettsia, Ehrlichia, Coxiella (EUWOG) in 1989 of which he is the President since 1999. He is member of the editorial board of Eur. J. Clin. Microbiol. Infect. Dis., J. Clin. Microbiol and Emer. Infect. Dis. He created alone in 1983 a research unit, “l’Unité des Rickettsies” which became National Reference Center in 1987, WHO Collaborative Center in 1988 and associated to CNRS (National Research Agency) in 1994. The laboratory currently is the largest in the world in the field of Rickettsial disease and 72 persons are working in it. Currently, this laboratory receive, from many countries, 10.000 samples per year for the diagnostic of Rickettsial diseases, tick bite infection, blood culture negative endocarditis and and unidentified infections.