Worldwide Distribution of Major Clones of Listeria monocytogenes
monocytogenes is worldwide a pathogen, but the geographic distribution of clones remains largely unknown. Genotyping of 300 isolates from the 5 continents and diverse sources showed the existence of few prevalent and globally distributed clones, some of which include previously described epidemic clones. Cosmopolitan distribution indicates the need for genotyping standardization.
Full-textDOI: · Available from: Alexandre Leclercq, Sep 28, 2015
- SourceAvailable from: Stephan Schmitz-Esser
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- "The other model states that persistence is largely a random process and that most L. monocytogenes strains can establish persistence if present in an appropriate niche at an appropriate time (Ferreira et al., 2014). Particularly L. monocytogenes strains of ST121 are often found in food production environments (Ragon et al., 2008; Parisi et al., 2010; Chenal-Francisque et al., 2011; Hein et al., 2011; Holch et al., 2013; Kastbjerg et al., 2014; Martin et al., 2014; Stessl et al., 2014; Wang et al., 2015). However, the molecular mechanisms underlying the phenomenon of persistence are currently unknown. "
ABSTRACT: The food-borne pathogen Listeria (L.) monocytogenes is often found in food production environments. Thus, controlling the occurrence of L. monocytogenes in food production is a great challenge for food safety. Among a great diversity of L. monocytogenes strains from food production, particularly strains belonging to sequence type (ST)121 are prevalent. The molecular reasons for the abundance of ST121 strains are however currently unknown. We therefore determined the genome sequences of three L. monocytogenes ST121 strains: 6179 and 4423, which persisted for up to eight years in food production plants in Ireland and Austria, and of the strain 3253 and compared them with available L. monocytogenes ST121 genomes. Our results show that the ST121 genomes are highly similar to each other and show a tremendously high degree of conservation among some of their prophages and particularly among their plasmids. This remarkably high level of conservation among prophages and plasmids suggests that strong selective pressure is acting on them. We thus hypothesize that plasmids and prophages are providing important adaptations for survival in food production environments. In addition, the ST121 genomes share common adaptations which might be related to their persistence in food production environments such as the presence of Tn6188, a transposon responsible for increased tolerance against quaternary ammonium compounds, a yet undescribed insertion harboring recombination hotspot (RHS) repeat proteins, which are most likely involved in competition against other bacteria, and presence of homologues of the L. innocua genes lin0464 and lin0465.Frontiers in Microbiology 04/2015; 6. DOI:10.3389/fmicb.2015.00380 · 3.99 Impact Factor
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- "These major clonal complexes are distributed worldwide (Chenal-Francisque et al., 2011). Interestingly, there is evidence that distribution of clones and serotypes differ among clinical, food and environmental isolates (Wiedmann et al., 1997; Gray et al., 2004; Ward et al., 2004; Chenal-Francisque et al., 2011). However, a limitation of these studies is that the collections of isolates that were analyzed are not fully representative of the complex ecology of members of the species L. monocytogenes. "
ABSTRACT: Listeria monocytogenes is the causative agent of the food-borne life threatening disease listeriosis. This pathogenic bacterium received much attention in the endeavor of deciphering the cellular mechanisms that underlie the onset of infection and its ability to adapt to the food processing environment. Although information is available on the presence of L. monocytogenes in many environmental niches including soil, water, plants, foodstuff and animals, understanding the ecology of L. monocytogenes in outdoor environments has received less attention. Soil is an environmental niche of pivotal importance in the transmission of this bacterium to plants and animals. Soil composition, microbial communities and macrofauna are extrinsic edaphic factors that direct the fate of L. monocytogenes in the soil environment. Moreover, farming practices may further affect its incidence. The genome of L. monocytogenes presents an extensive repertoire of genes encoding transport proteins and regulators, a characteristic of the genome of ubiquitous bacteria. Postgenomic analyses bring new insights in the process of soil adaptation. In the present paper focussing on soil, we review these extrinsic and intrinsic factors that drive environmental adaptation of L. monocytogenes.Frontiers in Cellular and Infection Microbiology 11/2013; 3:87. DOI:10.3389/fcimb.2013.00087 · 3.72 Impact Factor
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- "Subtype characterization of L. monocytogenes isolates from listeriosis outbreaks has suggested that many outbreaks were caused by a small number of L. monocytogenes epidemic clones , that is, by a closely related group of isolates that evolved clonally. Epidemic clones of L. monocytogenes have been implicated in several outbreaks and sporadic cases of listeriosis worldwide   , and for this reason, although not yet proven, they have been considered more virulent than other strains. "
ABSTRACT: Listeria was first described in 1926 by Murray, Webb, and Swann, who discovered it while investigating an epidemic infection among laboratory rabbits and guinea pigs. The role of Listeria monocytogenes as a foodborne pathogen was definitively recognized during the 1980s. This recognition was the consequence of a number of epidemic human outbreaks due to the consumption of contaminated foods, in Canada, in the USA and in Europe. Listeriosis is especially severe in immunocompromised individuals such as pregnant women. The disease has a low incidence of infection, although this is undeniably increasing, with a high fatality rate amongst those infected. In pregnant women listeriosis may cause abortion, fetal death, or neonatal morbidity in the form of septicemia and meningitis. Improved education concerning the disease, its transmission, and prevention measures for immunocompromised individuals and pregnant women has been identified as a pressing need.ISRN obstetrics and gynecology 09/2013; 2013(2):851712. DOI:10.1155/2013/851712