-
International Journal of Molecular... Feb 2023We explored the antimicrobial activity of sertraline on and further investigated the effects of sertraline on biofilm formation and the virulence gene expression of ....
We explored the antimicrobial activity of sertraline on and further investigated the effects of sertraline on biofilm formation and the virulence gene expression of . The minimum inhibitory concentration and minimum bactericidal concentration for sertraline against were in the range of 16-32 μg/mL and 64 μg/mL, respectively. Sertraline-dependent damage of the cell membrane and a decrease in intracellular ATP and pH in were observed. In addition, sertraline reduced the biofilm formation efficiency of the strains. Importantly, low concentrations (0.1 μg/mL and 1 μg/mL) of sertraline significantly down-regulated the expression levels of various virulence genes (, , , , , and ). These results collectively suggest a role of sertraline for the control of in the food industry.
Topics: Anti-Infective Agents; Bacterial Proteins; Gene Expression Regulation, Bacterial; Listeria monocytogenes; Sertraline; Virulence; Virulence Factors
PubMed: 36902108
DOI: 10.3390/ijms24054678 -
Cellular Microbiology Oct 2017Listeria monocytogenes, the causative agent of listeriosis, is an intracellular pathogen that is exquisitely evolved to survive and replicate in the cytosol of... (Review)
Review
Listeria monocytogenes, the causative agent of listeriosis, is an intracellular pathogen that is exquisitely evolved to survive and replicate in the cytosol of eukaryotic cells. Eukaryotic cells typically restrict bacteria from colonising the cytosol, likely through a combination of cell autonomous defences, nutritional immunity, and innate immune responses including induction of programmed cell death. This suggests that L. monocytogenes and other professional cytosolic pathogens possess unique metabolic adaptations, not only to support replication but also to facilitate resistance to host-derived stresses/defences and avoidance of innate immune activation. In this review, we outline our current understanding of L. monocytogenes metabolism in the host cytosol and highlight major metabolic processes which promote intracellular replication and survival.
Topics: Cytosol; Immunity, Innate; Listeria monocytogenes; Virulence
PubMed: 28656691
DOI: 10.1111/cmi.12762 -
Environmental Microbiology Dec 2020Listeria monocytogenes is a foodborne pathogen causing systemic infection with high mortality. To allow efficient tracking of outbreaks a clear definition of the genomic...
Listeria monocytogenes is a foodborne pathogen causing systemic infection with high mortality. To allow efficient tracking of outbreaks a clear definition of the genomic signature of a cluster of related isolates is required, but lineage-specific characteristics call for a more detailed understanding of evolution. In our work, we used core genome MLST (cgMLST) to identify new outbreaks combined to core genome SNP analysis to characterize the population structure and gene flow between lineages. Whilst analysing differences between the four lineages of L. monocytogenes we have detected differences in the recombination rate, and interestingly also divergence in the SNP differences between sub-lineages. In addition, the exchange of core genome variation between the lineages exhibited a distinct pattern, with lineage III being the best donor for horizontal gene transfer. Whilst attempting to link bacteriophage-mediated transduction to observed gene transfer, we found an inverse correlation between phage presence in a lineage and the extent of recombination. Irrespective of the profound differences in recombination rates observed between sub-lineages and lineages, we found that the previously proposed cut-off of 10 allelic differences in cgMLST can be still considered valid for the definition of a foodborne outbreak cluster of L. monocytogenes.
Topics: Bacteriophages; Evolution, Molecular; Gene Flow; Gene Transfer, Horizontal; Genetic Variation; Genome, Bacterial; Listeria monocytogenes; Listeriosis; Multilocus Sequence Typing; Phylogeny; Polymorphism, Single Nucleotide; Recombination, Genetic
PubMed: 32483914
DOI: 10.1111/1462-2920.15111 -
Microbial Biotechnology Jul 2021Listeria monocytogenes is a highly pathogenic foodborne bacterium that is ubiquitous in the natural environment and capable of forming persistent biofilms in food... (Review)
Review
Listeria monocytogenes is a highly pathogenic foodborne bacterium that is ubiquitous in the natural environment and capable of forming persistent biofilms in food processing environments. This species has a rich repertoire of surface structures that enable it to survive, adapt and persist in various environments and promote biofilm formation. We review current understanding and advances on how L. monocytogenes organizes its surface for biofilm formation on surfaces associated with food processing settings, because they may be an important target for development of novel antibiofilm compounds. A synthesis of the current knowledge on the role of Listeria surfactome, comprising peptidoglycan, teichoic acids and cell wall proteins, during biofilm formation on abiotic surfaces is provided. We consider indications gained from genome-wide studies and discuss surfactome structures with established mechanistic aspects in biofilm formation. Additionally, we look at the analogies to the species L. innocua, which is closely related to L. monocytogenes and often used as its model (surrogate) organism.
Topics: Biofilms; Cell Wall; Food Handling; Listeria monocytogenes
PubMed: 34106516
DOI: 10.1111/1751-7915.13847 -
Microbiology Spectrum Dec 2021The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in...
The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in order to ensure their long-term survival under adverse conditions. Exposure of Listeria monocytogenes cells to sublethal stressors related to food processing may induce sublethal injury and the viable-but-nonculturable (VBNC) state. In this study, exposure to acetic acid (AA), hydrochloric acid (HCl), and two disinfectants, peracetic acid (PAA) and sodium hypochlorite (SH), at 20°C and 4°C was used to evaluate the potential induction of L. monocytogenes strain Scott A into different stages of dormancy. To differentiate the noninjured subpopulation from the total population, tryptic soy agar with 0.6% yeast extract (TSAYE), supplemented or not with 5% NaCl, was used. Sublethally injured and VBNC cells were detected by comparing plate counts obtained with fluorescence microscopy and by using combinations of carboxyfluorescein and propidium iodide (viable/dead cells). Induction of sublethal injury was more intense after PAA treatment. Two subpopulations were detected, with phenotypes of untreated cells and small colony variants (SCVs). SCVs appeared as smaller colonies of various sizes and were first observed after 5 min of exposure to 5 ppm PAA at 20°C. Increasing the stress intensity from 5 to 40 ppm PAA led to earlier detection of SCVs. L. monocytogenes remained culturable after exposure to 20 and 30 ppm PAA for 3 h. At 40 ppm, after 3 h of exposure, the whole population was considered nonculturable, while cells remained metabolically active. These results corroborate the induction of the VBNC state. Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product's microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health. Induction of the VBNC state is crucial for foodborne pathogens, such as L. monocytogenes, the detection of which relies almost exclusively on the use of culture recovery techniques. In the present study, we confirmed that sublethal injury is an initial stage of dormancy in L. monocytogenes that is followed by the VBNC state. Our results showed that PAA induced SCVs (a phenomenon potentially triggered by external factors) and the VBNC state in L. monocytogenes, indicating that tests of lethality based only on culturability may provide false-positive results regarding the effectiveness of an inactivation treatment.
Topics: Acetic Acid; Disinfectants; Food Contamination; Food Handling; Food Microbiology; Foodborne Diseases; Humans; Hydrochloric Acid; Listeria monocytogenes; Listeriosis; Peracetic Acid; Sodium Hypochlorite
PubMed: 34908469
DOI: 10.1128/Spectrum.01377-21 -
Applied Microbiology and Biotechnology Jun 2016The genus Listeria is currently comprised of 17 species, including 9 Listeria species newly described since 2009. Genomic and phenotypic data clearly define a distinct... (Review)
Review
The genus Listeria is currently comprised of 17 species, including 9 Listeria species newly described since 2009. Genomic and phenotypic data clearly define a distinct group of six species (Listeria sensu strictu) that share common phenotypic characteristics (e.g., ability to grow at low temperature, flagellar motility); this group includes the pathogen Listeria monocytogenes. The other 11 species (Listeria sensu lato) represent three distinct monophyletic groups, which may warrant recognition as separate genera. These three proposed genera do not contain pathogens, are non-motile (except for Listeria grayi), are able to reduce nitrate (except for Listeria floridensis), and are negative for the Voges-Proskauer test (except for L. grayi). Unlike all other Listeria species, species in the proposed new genus Mesolisteria are not able to grow below 7 °C. While most new Listeria species have only been identified in a few countries, the availability of molecular tools for rapid characterization of putative Listeria isolates will likely lead to future identification of isolates representing these new species from different sources. Identification of Listeria sensu lato isolates has not only allowed for a better understanding of the evolution of Listeria and virulence characteristics in Listeria but also has practical implications as detection of Listeria species is often used by the food industry as a marker to detect conditions that allow for presence, growth, and persistence of L. monocytogenes. This review will provide a comprehensive critical summary of our current understanding of the characteristics and distribution of the new Listeria species with a focus on Listeria sensu lato.
Topics: Biological Evolution; Genome, Bacterial; Listeria; Listeria monocytogenes; Phylogeny; Species Specificity; Virulence
PubMed: 27129530
DOI: 10.1007/s00253-016-7552-2 -
Current Opinion in Microbiology Feb 2019Listeria monocytogenes (Lm) is a Gram-positive bacterium that thrives in nature as a saprophyte and in the mammalian host as an intracellular pathogen. Both environments... (Review)
Review
Listeria monocytogenes (Lm) is a Gram-positive bacterium that thrives in nature as a saprophyte and in the mammalian host as an intracellular pathogen. Both environments pose potential danger in the form of redox stress. In addition, endogenous reactive oxygen species (ROS) are continuously generated as by-products of aerobic metabolism. Redox stress from ROS can damage proteins, lipids, and DNA, making it highly advantageous for bacteria to evolve mechanisms to sense and detoxify ROS. This review focuses on the five redox-responsive regulators in Lm: OhrR (to sense organic hydroperoxides), PerR (peroxides), Rex (NAD/NADH homeostasis), SpxA1/2 (disulfide stress), and PrfA (redox stress during infection).
Topics: Gene Expression Regulation, Bacterial; Listeria monocytogenes; Metabolic Networks and Pathways; Oxidation-Reduction; Reactive Oxygen Species
PubMed: 30412828
DOI: 10.1016/j.mib.2018.10.006 -
Nature Communications Nov 2021Listeria genus comprises two pathogenic species, L. monocytogenes (Lm) and L. ivanovii, and non-pathogenic species. All can thrive as saprophytes, whereas only...
Listeria genus comprises two pathogenic species, L. monocytogenes (Lm) and L. ivanovii, and non-pathogenic species. All can thrive as saprophytes, whereas only pathogenic species cause systemic infections. Identifying Listeria species' respective biotopes is critical to understand the ecological contribution of Listeria virulence. In order to investigate the prevalence and abundance of Listeria species in various sources, we retrieved and analyzed 16S rRNA datasets from MG-RAST metagenomic database. 26% of datasets contain Listeria sensu stricto sequences, and Lm is the most prevalent species, most abundant in soil and host-associated environments, including 5% of human stools. Lm is also detected in 10% of human stool samples from an independent cohort of 900 healthy asymptomatic donors. A specific microbiota signature is associated with Lm faecal carriage, both in humans and experimentally inoculated mice, in which it precedes Lm faecal carriage. These results indicate that Lm faecal carriage is common and depends on the gut microbiota, and suggest that Lm faecal carriage is a crucial yet overlooked consequence of its virulence.
Topics: Animals; Carrier State; DNA, Bacterial; Datasets as Topic; Disease Models, Animal; Feces; Gastrointestinal Microbiome; Humans; Listeria monocytogenes; Male; Metagenomics; Mice; Phylogeny; RNA, Ribosomal, 16S; Virulence
PubMed: 34819495
DOI: 10.1038/s41467-021-27069-y -
Food Microbiology Apr 2022Listeria monocytogenes remains a threat to the food system and has led to numerous foodborne outbreaks worldwide. L. monocytogenes can establish itself in food...
Listeria monocytogenes remains a threat to the food system and has led to numerous foodborne outbreaks worldwide. L. monocytogenes can establish itself in food production facilities by adhering to surfaces, resulting in increased resistance to environmental stressors. The aim of this study was to evaluate the adhesion ability of L. monocytogenes at 8 °C and to analyse associations between the observed phenotypes and genetic factors such as internalin A (inlA) genotypes, stress survival islet 1 (SSI-1) genotype, and clonal complex (CC). L. monocytogenes isolates (n = 184) were grown at 8 °C and 100% relative humidity for 15 days. The growth was measured by optical density at 600 nm every 24 h. Adherent cells were stained using crystal violet and quantified spectrophotometrically. Genotyping of inlA and SSI-1, multi-locus sequence typing, and a genome-wide association study (GWAS) were performed to elucidate the phenotype-genotype relationships in L. monocytogenes cold adhesion. Among all inlA genotypes, truncated inlA isolates had the highest mean adhered cells, ABS595nm = 0.30 ± 0.15 (Tukey HSD; P < 0.05), while three-codon deletion inlA isolates had the least mean adhered cells (Tukey HSD; P < 0.05). When SSI-1 was present, more cells adhered; less cells adhered when SSI-1 was absent (Welch's t-test; P < 0.05). Adhesion was associated with clonal complexes which have low clinical frequency, while reduced adhesion was associated with clonal complexes which have high frequency. The results of this study support that premature stop codons in the virulence gene inlA are associated with increased cold adhesion and that an invasion enhancing deletion in inlA is associated with decreased cold adhesion. This study also provides evidence to suggest that there is an evolutionary trade off between virulence and adhesion in L. monocytogenes. These results provide a greater understanding of L. monocytogenes adhesion which will aid in the development of strategies to reduce L. monocytogenes in the food system.
Topics: Bacterial Adhesion; Bacterial Proteins; Food Microbiology; Genetic Association Studies; Genomics; Listeria monocytogenes; Multilocus Sequence Typing; Mutation; Polystyrenes
PubMed: 34809941
DOI: 10.1016/j.fm.2021.103915 -
MicrobiologyOpen Nov 2021Listeria monocytogenes is a human pathogen. It is the causative agent of listeriosis, the leading cause of bacterial-linked foodborne mortality in Europe and elsewhere.... (Review)
Review
Listeria monocytogenes is a human pathogen. It is the causative agent of listeriosis, the leading cause of bacterial-linked foodborne mortality in Europe and elsewhere. Outbreaks of listeriosis have been associated with the consumption of fresh produce including vegetables and fruits. In this review we summarize current data providing direct or indirect evidence that plants can serve as habitat for L. monocytogenes, enabling this human pathogen to survive and grow. The current knowledge of the mechanisms involved in the interaction of this bacterium with plants is addressed, and whether this foodborne pathogen elicits an immune response in plants is discussed.
Topics: Disease Outbreaks; Food Microbiology; Foodborne Diseases; Host Microbial Interactions; Humans; Listeria monocytogenes; Listeriosis; Microbial Interactions; Microbial Viability; Microbiota; Plant Immunity; Plants; Vegetables
PubMed: 34964288
DOI: 10.1002/mbo3.1255