“Epidemic Clones” of Listeria monocytogenes Are Widespread and Ancient Clonal Groups

Thomas Cantinelli (1, 2, 3) , Viviane Chenal-Francisque (1, 2, 3) , Laure Diancourt (4) , Lise Frezal (5) , Alexandre Leclercq (1, 2, 3) , Thierry Wirth (6) , Marc Lecuit (3, 1, 2, 7, 8, 9, 10) , Sylvain Brisse (11)

1 CNRL - Centre National de Référence Listeria - National Reference Center Listeria
2 CC-OMS / WHO-CC - Centre collaborateur de l'OMS Listeria / WHO Collaborating Centre Listeria
3 Biologie des Infections - Biology of Infection
4 PF8 - Génotypage des Pathogènes et Santé Publique (Plate-forme)
5 IBENS - Institut de biologie de l'ENS Paris
6 EPHE - École Pratique des Hautes Études
7 UPD5 - Université Paris Descartes - Paris 5
8 Hôpital Necker - Enfants Malades [AP-HP]
9 Service des Maladies infectieuses et tropicales [CHU Necker]
10 Imagine - U1163 - Imagine - Institut des maladies génétiques (IHU)
11 Génomique évolutive des Microbes / Microbial Evolutionary Genomics

The food-borne pathogen Listeria monocytogenes is genetically heterogeneous. Although some clonal groups have been implicated in multiple outbreaks, there is currently no consensus on how "epidemic clones" should be defined. The objectives of this work were to compare the patterns of sequence diversity on two sets of genes that have been widely used to define L. monocyto-genes clonal groups: multilocus sequence typing (MLST) and multi-virulence-locus sequence typing (MvLST). Further, we evaluated the diversity within clonal groups by pulsed-field gel electrophoresis (PFGE). Based on 125 isolates of diverse temporal, geographical , and source origins, MLST and MvLST genes (i) had similar patterns of sequence polymorphisms, recombination, and selection, (ii) provided concordant phylogenetic clustering, and (iii) had similar discriminatory power, which was not improved when we combined both data sets. Inclusion of representative strains of previous outbreaks demonstrated the correspondence of epidemic clones with previously recognized MLST clonal complexes. PFGE analysis demonstrated heterogeneity within major clones, most of which were isolated decades before their involvement in outbreaks. We conclude that the "epidemic clone" denominations represent a redundant but largely incomplete nomenclature system for MLST-defined clones, which must be regarded as successful genetic groups that are widely distributed across time and space.

Domains: Life Sciences [q-bio]; Human health and pathology; Infectious diseases; Microbiology and Parasitology; Bacteriology

Thomas Cantinelli, Viviane Chenal-Francisque, Laure Diancourt, Lise Frezal, Alexandre Leclercq, et al.. “Epidemic Clones” of Listeria monocytogenes Are Widespread and Ancient Clonal Groups. Journal of Clinical Microbiology, 2013, 51 (11), pp.3770-3779. ⟨10.1128/JCM.01874-13⟩. ⟨pasteur-02869829⟩