Thomas Brauge

• PhD; HDR
• Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail

The wall teichoic acid (WTA) is the major carbohydrate found within the extracellular matrix of the Listeria monocytogenes biofilm. We first addressed the frequency of spontaneous mutations in two genes (lmo2549 and lmo2550) responsible for the GlcNAcylation in 93 serotype 1/2a strains that were mainly isolated from seafood industries. We studied t...

This study was designed to assess the efficiency of eight extraction methods regarding their ability to release superficial (exogenous) and intracellular (endogenous) DNA from B. cereus spores for subsequent analysis by quantitative PCR (qPCR). B. cereus spore suspensions were subjected to both commercial DNA extraction kits and mechanical DNA extr...

Seafood products are widely consumed all around the world and play a significant role on the economic market. Bacteria of the Vibrio genus can contaminate seafood and thus pose a risk to human health. Three main Vibrio species, V. cholerae, V. parahaemolyticus and V. vulnificus, are potentially pathogenic to humans. These species are responsible fo...

The aim of this study was to characterize the Listeria monocytogenes biofilm and particularly the nature of the carbohydrates in the biofilm extracellular matrix and culture supernatant versus to cell wall carbohydrates. L. monocytogenes serotype 1/2a and 4b strains were able to form complex biofilms embedded in an extracellular matrix. The soluble...

Foodborne pathogens are responsible of foodborne diseases and food poisoning and thus pose a great threat to food safety. These microorganisms can adhere to surface and form a biofilm composed of an extracellular matrix. This extracellular matrix protects bacterial cells from industrial environmental stress factors such as cleaning and disinfection...

The performance of a new method developed in 2021 by the European Union Reference Laboratory (EURL) for Listeria monocytogenes based on 12 multiplex real-time PCR, allowing the identification of the molecular serotype and the 30 major L. monocytogenes multilocus sequence typing clonal complexes (CC), was assessed through a European interlaboratory...

This study assessed the impact of six disinfectant-neutralizing buffers on Listeria monocytogenes adhering to stainless steel surfaces treated with quaternary ammonium or hydrogen peroxide-based disinfectants. The goal was to evaluate potential stressors induced by these buffers during sampling, minimizing false negatives in food industry surface m...

Background In the context of pathogen surveillance, it is crucial to ensure interoperability and harmonized data. Several surveillance systems are designed to compare bacteria and identify outbreak clusters based on core genome MultiLocus Sequence Typing (cgMLST). Among the different approaches available to generate bacterial cgMLST, our research u...

Foodborne pathogens are responsible for foodborne diseases and food poisoning and thus pose a great threat to food safety. These microorganisms can adhere to surface and form a biofilm composed of an extracellular matrix. This matrix protects bacterial cells from industrial environmental stress factors such as cleaning and disinfection operations....

Background In the context of pathogen surveillance, it is crucial to ensure interoperability and harmonized data. Several surveillance systems are designed to compare bacteria and identify outbreak clusters based on core genome MultiLocus Sequence Typing (cgMLST). Among the different approaches available to generate bacterial cgMLST, our research u...

Vibrio parahaemolyticus is a threat to human health and one of the leading bacterial causes of seafood-borne infection worldwide. This pathogen is autochtonous in the marine environment and is able to acquire antimicrobial resistance (AMR) mechanisms, which is a global concern. However, the emergence of AMR V. parahaemolyticus strains in seafood is...

Tout au long de la chaîne alimentaire, les aliments peuvent être exposés à des agents pathogènes qui peuvent affecter leur qualité et donc la santé des consommateurs. Cet ouvrage traite de la gestion des risques et spécifiquement les risques microbiologiques.Après le stade de la production primaire, avoir une bonne connaissance des stratégies et de...

Tout au long de la chaîne alimentaire, les aliments peuvent être exposés à des agents pathogènes qui peuvent affecter leur qualité et donc la santé des consommateurs. Cet ouvrage traite de la gestion des risques et spécifiquement les risques microbiologiques.Après le stade de la production primaire, avoir une bonne connaissance des stratégies et de...

Phytoplankton and zooplankton play a crucial role in marine ecosystems as the basis of the food webs but are also vulnerable to environmental pollutants. Among emerging pollutants, antimicrobial resistance (AMR) is a major public health problem encountered in all environmental compartments. However, the role of planktonic communities in its dissemi...

Vibrio spp. are opportunistic human and animal pathogens found ubiquitously in marine environments. Globally, there is a predicted rise in the prevalence of Vibrio spp. due to increasing ocean temperatures, which carries significant implications for public health and the seafood industry. Consequently, there is an urgent need for enhanced strategie...

Staphylococcus is a significant food safety hazard. The marine environment serves as a source of food for humans and is subject to various human-induced discharges, which may contain Staphylococcus strains associated with antimicrobial resistance (AMR). The aim of this study was to assess the occurrence and geographical distribution of AMR Staphylo...

Vibrio spp., known human foodborne pathogens, thrive in freshwater, estuaries, and marine settings, causing vibriosis upon ingestion. The rising global vibriosis cases due to climate change necessitate a deeper understanding of Vibrio epidemiology and human transmission. This review delves into Vibrio contamination in seafood, scrutinizing its sour...

Smoked salmon and smoked trout are ready-to-eat and potentially contaminated with the pathogenic bacterium Listeria monocytogenes making them high risk for the consumer. This raises questions about the presence of hypervirulent or persistent strains in the salmon and trout industries. Knowledge of the genetic diversity of circulating strains in the...

Listeria monocytogenes is a ubiquitous bacterium that causes a foodborne illness, listeriosis. Most strains can be classified into major clonal complexes (CCs) that account for the majority of outbreaks and sporadic cases in Europe. In addition to the 20 CCs known to account for the majority of human and animal clinical cases, 10 CCs are frequently...

An innovative approach, Raman microspectroscopy coupled with deuterium isotope probing (Raman-DIP), can be used to evaluate the metabolism of deuterated carbon source in bacteria and also to presume different anabolic pathways. This method requires the treatment of cells with heavy water that could affect the bacterial viability state at higher con...

Les denrées alimentaires peuvent être le vecteur de dangers de différentes natures induisant des effets néfastes sur la santé du consommateur. Les virus sont les premières causes de maladies infectieuses d’origine alimentaire alors que les bactéries pathogènes et les toxines bactériennes demeurent les premiers agents de maladies zoonotiques en Euro...

To investigate the microbial community in the marine environment by molecular approaches, it is important to extract DNA in sufficient quantity and purity. The presence of inhibitors in the samples can lead to false negative results or a loss of information, but can be highlighted by a process control in the experiments. We compared seven bacterial...

For many years, numerous nutritional virtues of benefit to human health have been attributed to seafood products. The seafood products covered by this European regulation are shellfish and ready‐to‐eat products. Escherichia coli should be tested for in peeled and shucked, cooked crustacean and mollusk products in live bivalve mollusks and live tuni...

From a global view of antimicrobial resistance over different sectors, seafood and the marine environment are often considered as potential reservoirs of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs); however, there are few studies and sparse results on this sector. This study aims to provide new data and insights regardi...

The marine environment is a potential natural reservoir of antimicrobial resistance genes (ARGs), subject to anthropogenic effluents (wastewater, industrial, and domestic), and known as a final receiving system. The aim of this study was to investigate the abundance and geographical distribution of the three blaTEM, sul1, and intI1 genes, proposed...

The superfamily Opisthorchioidea encompasses the families Cryptogonimidae, Opisthorchiidae and Heterophyidae. These parasites depend on the aquatic environment and include marine and freshwater species. Some species, such as Clonorchis sinensis and Opisthorchis viverrini, have a high impact on public health with millions of infected people worldwid...

We evaluated the performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) associated with the Bruker BioTyperTM V7.0.0 database for the identification of 713 bacterial strains isolated from seafood products and sea water samples (ANSES B3PA collection) under culture conditions that may have been sig...

The objectives of this study were 1) to evaluate the impact of two industrial disinfectants on the viability of Listeria monocytogenes populations in biofilm and 2) to investigate the viability state of L. monocytogenes cells present on contact surfaces in the smoked salmon processing environment. In the first step, we cultured mono species and mix...

The ready-to-eat products can be contaminated during processing by pathogen or spoilage bacteria, which persist in the industrial environment. Some bacterial species are able to form biofilms which protect them from environmental conditions. To check the bacterial contamination of the surfaces in the food industries, the professionals must regularl...

Aims The aim of this study was to evaluate the performance of sampling methods [contact plates, sponges, and swabs] in the recovery of biofilm Listeria monocytogenes populations considering the seafood environment conditions (nature of conditioning, of materials and bacterial species). Methods and results Different materials (stainless steel, poly...

Listeria monocytogenesClonal Complexes (CCs) have been epidemiologically associated with foods, especially ready-to-eat (RTE) products for which the most likely source of contamination depends on the occurrence of persisting clones in food-processing environments (FPEs). As the ability of L. monocytogenes to adapt to environmental stressors met in...

Assessment of microorganism viability is useful in many industrial fields. A large number of methods associated with the use of fluorescent probes have been developed, including fluorimetry, fluorescence microscopy, and cytometry. In this study, a microvolume spectrofluorometer was used to measure the membrane potential variations of Escherichia co...

The viable but not culturable (VBNC) state is a survival strategy implemented by bacteria in response to adverse environmental conditions. VBNC bacteria remain metabolically active but can no longer be detected on conventional culture media. These characteristics of VBNC cells pose a risk for food safety as pathogens may not be detected in the proc...

Assessment of micro-organism viability is useful in many industrial fields. A large number of methods associated with the use of fluorescent probes have been developed including fluorimetry, fluorescence microscopy, and cytometry. In this study, a microvolume spectrofluorometer was used to measure the membrane potential variations of Escherichia co...

Accession numbers of any nucleotide sequence data. (PDF)

Dendrogram of obtained using ApaI and AscI enzymes demonstrating the genetic diversity of L. monocytogenes isolates. (PDF)

Growth of the wild-type EGD-e strain, DSS 1130 BFA2, EGD-eΔlmo2549 and EGD-eΔlmo2550 mutants and the complemented mutants EGD-e Δlmo2549:: pLIV2(lmo2549) and EGD-e Δlmo2550:: pLIV2(lmo2550) at 30°C in MCDB202 medium during 48 h. (PDF)

Thoracic disc herniation is a rare pathology for which surgical treatment is difficult. The discovery of asymptomatic or only slightly symptomatic lesions can be problematic, especially in cases of marked canal stenosis. The possibility of spontaneous resorption has been documented by a few case reports but there is no study on this subject. Our ob...

Biofilms form ecological niches enhancing bacterial tolerance to cleaning and disinfection treatments and thus contributing to the persistence of these microorganisms in food-processing environments. Those biofilms can be involved in food contamination and consequently need to be better characterized in order to evaluate their impact on food safety...

Various types of surface are used in the food industry and are subject to contamination by microorganisms which can be organized into biofilm. Biofilm is a microorganism complex community that adhere on surface and embedded in an extracellular matrix. The objective of this study was therefore to evaluate the effectiveness of four recovery methods d...

Listeriosis is caused by the food-borne pathogen Listeria monocytogenes, which can be found in seafood products and processing plants. Furthermore, it can form biofilms with dead, viable culturable and viable but non culturable cells (VBNC) bacterial populations, which makes it resistant against cleaning and disinfection operations. The microbiolog...

L’objectif de ces travaux a été d’étudier le rôle des exopolysaccharides dans la formation des biofilms de Listeria monocytogenes et dans leur résistance face à des procédures de nettoyage rencontrées en entreprise dans des circuits fermés. Nous avons montré que l’exopolysaccharide majeur présent dans la matrice extracellulaire des biofilms de L. m...

Listeria monocytogenes (L. monocytogenes ) is a pathogenic bacterium implicated in foodborne infections cause listeriosis, an uncommon disease but with a mortality rate of 12.7% in humans (EFSA, 2011) . Seventeen serotypes are distinguished in the species L. monocytogenes, the most widespread in the foodborne infection are serotypes 1/2a (serogroup...