|Director : MARTIN Paul (firstname.lastname@example.org)|
National Reference Center of Listeria : Laboratory-based surveillance of listeriosis and participation in investigations of listeriosis epidemiology in France.
World Health Organization Collaborating Center for Foodborne Listeriosis : Participation in laboratory-based surveillance of listeriosis in some Countries, multicenter study on L. monocytogenes typing.
Research : characterization of two populations of L. monocytogenes (strains isolated from humans and from foods) by their virulence proteins profiles, development of DNA micro-arrays for typing and epidemiological studies.
National Reference Centre (CNR) for Listeria:
Situation with respect to human listeriosis in 2000, according to the results of the CNR :
Two hundred and sixteen sporadic cases were registered in 2000, based on the strains received by the CNR. The clinical forms were distributed as follows: 48 (22%) maternal and neonatal forms and 168 (78%) non-maternal and non-neonatal forms. A large decrease in the number of perinatal forms was observed in 1994 and the number of perinatal forms has steadily decreased ever since. The non-perinatal forms were distributed as follows: 110 cases (65%) of bacteraemia/septicaemia, 42 cases (25%) of central nervous system infection and 16 cases (10%) of other forms. This distribution is similar to that observed in 1999.
Between 1996 and 2000, the annual number of cases of listeriosis was between 216 and 230. The results for 2000 therefore confirm the large decrease in the number of cases observed since 1996 (301 cases in 1995). This decrease must be seen in the light of the measures taken concerning the production and distribution of foodstuffs and the recommendations given to populations at risk.
WHO Collaborating Centre (WHOCC) for food-borne listeriosis :
Study of virulence proteins in L. monocytogenes.
Several observations have suggested that certain strains present in food may be less frequently responsible for infections in humans. These observations include the non-uniform distribution of serovars, ribovars, isoenzyme profiles and surface proteins according to whether the strain is of human or food origin. Further evidence that this may be the case is provided by heterogeneity in the virulence of strains in animal and cell models. The work carried out by the "Unité des InteractionsBactéries-Cellules" has demonstrated molecular mechanisms for host invasion in L. monocytogenes. A study of the expression of several virulence factors involved in various stages of the infections cycle is being carried out in collaboration with this unit, to compare clinical strains and strains isolated from food. Having compared expression of the virulence genes encoding listeriolysin O (LLO), Act A (involved in actin polymerisation), Ami (bacteriolysin) and InlB (required for entry into host cells) in 300 strains of Listeria monocytogenes isolated from sporadic human cases and 150 strains isolated from foods, attention is currently focused on the gene encoding InlA, which is required for the entry of the bacterium into human intestinal cells.
General approach to the epidemiology of listeriosis.
This programme involves three groups from the Pasteur Institute. Its principal aim is to identify differences between the genomes of L. monocytogenes (a species pathogenic in humans) and L. innocua (a non-pathogenic species) with a view to developing new tools for the epidemiology and typing of Listeria monocytogenes and to improving our understanding of the virulence mechanisms of this species. The laboratory is primarily involved in epidemiological aspects, for the development of a new method of typing for L. monocytogenes based on DNA microarrays.
|Publications of the unit on Pasteur's references database|
|Office staff||Researchers||Scientific trainees||Other personnel|
Christine PHAN - email@example.com
Malika GOUALI (chercheur temporaire)
Michel DOUMITH (chercheur temporaire)