Listeriosis: A Primer

Department of Pediatrics, IWK Health Centre and Dalhousie University, Halifax, NS.
Canadian Medical Association Journal (Impact Factor: 5.96). 10/2008; 179(8):795-7. DOI: 10.1503/cmaj.081377
Source: PubMed
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    • "Listeria monocytogenes is the causative agent of listeriosis, a foodborne disease which affects the elderly, pregnant women, unborn and newborn babies and people with weakened immune systems (Allerberger and Wagner, 2010). In healthy adults and children, listeriosis causes few or no symptoms and may be mistaken for a mild viral infection or flu which makes the incidence of listeriosis difficult to establish (Bortolussi, 2008). However, an increasing rate of this foodborne illness has been reported in Europe in recent years related to a higher rate of listeriosis in people ≥65 years of age (Goulet et al., 2008). "
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    ABSTRACT: Bacteriophages and bacteriocins are promising biocontrol tools in food. In this work, two Listeria bacteriophages, FWLLm1 and FWLLm3, were assessed in combination with the bacteriocin coagulin C23 to inhibit Listeria monocytogenes. Preliminary results under laboratory conditions demonstrated that both antimicrobials act synergistically when they were applied in suboptimal concentrations. The combined approach was further assessed in milk contaminated with 5×10(4)CFU/ml L. monocytogenes 2000/47 and stored at 4°C for 10days. When used alone, phage FWLLm1 added at 5×10(6)PFU/ml, FWLLm3 at 5×10(5)PFU/ml and coagulin C23 at 584AU/ml kept L. monocytogenes 2000/47 counts lower than the untreated control throughout storage. However, when used in combination, inhibition was enhanced and in the presence of FWLLm1 and coagulin C23, L. monocytogenes 2000/47 counts were under the detection limits (less than 10CFU/ml) from day 4 until the end of the experiment. Resistant mutants towards phages and coagulin C23 could be obtained, but cross-resistance was not detected. Mutants resistant to FWLLm3 and coagulin C23 were also recovered from surviving colonies after cold storage in milk which may explain the failure of this combination to inhibit L. monocytogenes. Remarkably, the fraction of resistant mutants isolated from the combined treatment was lower than that from each antimicrobial alone, suggesting that synergy between bacteriocins and phages could be due to a lower rate of resistance development and the absence of cross-resistance. Copyright © 2015 Elsevier B.V. All rights reserved.
    International Journal of Food Microbiology 07/2015; 205:68-72. DOI:10.1016/j.ijfoodmicro.2015.04.007 · 3.08 Impact Factor
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    • "Therefore we define V to be the maximum of r · s i.i.d. uniform random variables defined on [0] [1]: "
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    ABSTRACT: The aim of this work is to present a MP test for extreme monotone randomized models. In particular it tests whether the extreme event of a sample comes from the same distribution as the other data. The application we present concerns the detection of epidemics of listeriosis in Lombardy from 2005 to 2011.
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    • "Listeria monocytogenes is a Gram-positive soil saprophyte and causative agent of a human foodborne infectious disease, listeriosis. L. monocytogenes infection in healthy adults may result in a spectrum of clinical illnesses ranging from general influenza-like symptoms such as fever, chills, and headache, to gastrointestinal symptoms including vomiting and diarrhea, which usually last one to four days in duration [1]–[3]. However, for immunocompromised individuals, such as infants, the elderly and pregnant women, listeriosis infections typically develop to more severe complications such as meningitis and encephalitis [1], [4], [5] leading to a mortality rate of 20% [1], [6]. "
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    ABSTRACT: Listeria monocytogenes is a foodborne bacterial pathogen and the causative agent of an infectious disease, listeriosis. L. monocytogenes is ubiquitous in nature and has the ability to persist in food processing environments for extended periods of time by forming biofilms and resisting industrial sanitization. Human listeriosis outbreaks are commonly linked to contaminated dairy products, ready-to-eat meats, and in recent years, fresh produce such as lettuce and cantaloupes. We identified a putative Crp/Fnr family transcription factor Lmo0753 that is highly specific to human-associated genetic lineages of L. monocytogenes. Lmo0753 possesses two conserved functional domains similar to the major virulence regulator PrfA in L. monocytogenes. To determine if Lmo0753 is involved in environmental persistence-related mechanisms, we compared lmo0753 deletion mutants with respective wild type and complementation mutants of two fully sequenced L. monocytogenes genetic lineage II strains 10403S and EGDe for the relative ability of growth under different nutrient availability and temperatures, soil survival, biofilm productivity and attachment to select fresh produce surfaces including romaine lettuce leaves and cantaloupe rinds. Our results collectively suggested that Lmo0753 plays an important role in L. monocytogenes biofilm production and attachment to fresh produce, which may contribute to the environmental persistence and recent emergence of this pathogen in human listeriosis outbreaks linked to fresh produce.
    PLoS ONE 09/2013; 8(9):e75736. DOI:10.1371/journal.pone.0075736 · 3.23 Impact Factor
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