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Proteomics Sep 2022Listeria monocytogenes is one of the main foodborne pathogens worldwide. Although its response to stress conditions has been extensively studied, it is still present in...
Listeria monocytogenes is one of the main foodborne pathogens worldwide. Although its response to stress conditions has been extensively studied, it is still present in the food processing environments and is a concern for consumers. To investigate how this microorganism adapts its proteome in mild stress conditions, a combined proteomics and bioinformatics approach was used to characterize the immunogenic protein profile of a sequence type 7 (ST7) strain that caused severe listeriosis outbreaks in central Italy. Extracted proteins were analyzed by immunoblotting using positive sera against L. monocytogenes and nLC-ESI-MS/MS, and all data were examined by five software to predict subcellular localization (SCL). A total of 226 proteins were extracted from the bands of interest, 58 of which were classified as potential immunogenic antigens. Compared to control cells grown under optimal conditions, six proteins, some of which under-described, were expressed under mild acid and salt stress conditions and/or at 12°C. In particular, adaptation and shaping of the proteome mainly involved cell motility at 12°C without acid and salt stress, whereas the combination of the same temperature with mild acid and salt stress induced a response concerning carbohydrate metabolism, oxidative stress, and DNA repair. Raw data are available via ProteomeXchange with identifier PXD033519.
Topics: Acids; Listeria monocytogenes; Proteome; Salt Stress; Tandem Mass Spectrometry
PubMed: 35916071
DOI: 10.1002/pmic.202200082 -
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 -
International Journal of Food... Feb 2021The aim of the present study is to investigate the prevalence and genetic diversity of Listeria monocytogenes in various fresh and frozen vegetable products available in...
The aim of the present study is to investigate the prevalence and genetic diversity of Listeria monocytogenes in various fresh and frozen vegetable products available in Poland. The samples were collected at retail market within the framework of national official control and monitoring program. In the years 2016-2019 a total of 49 samples out of 8712 collected vegetable samples were positive for L. monocytogenes. Our findings demonstrated that the occurrence of L. monocytogenes in various vegetable products was generally low, on average only 0.56% in the studied years. All isolates were susceptible to 11 antimicrobial agents: penicillin, ampicillin, meropenem, erythromycin, sulfamethoxazole-trimethoprim, amoxicillin-clavulanic acid, ciprofloxacin, chloramphenicol, gentamicin, vancomycin, and tetracycline. All of them harbored virulence-associated genes (inlA, inlC, and lmo2672), 82% harbored inlJ gene and few of them (22%) also possessed the llsX gene. The majority of collected isolates (65%) belonged to molecular serogroup 1/2a-3a, followed by 4ab-4b-4d-4e (33%), and only one to serogroup 1/2b-3b-7 (2%). Isolates yielded 18 different restriction profiles, revealing a large cluster of contamination linked to frozen corn (21 strains) and distributed in 3 pulsotypes. MLST analysis classified selected isolates into nine clonal complexes (CCs). The obtained results contribute to characterizing the diversity of L. monocytogenes isolated from various vegetable products in Poland and their impact on food safety and public health.
Topics: Anti-Bacterial Agents; Food Microbiology; Genetic Variation; Humans; Incidence; Listeria monocytogenes; Multilocus Sequence Typing; Poland; Serogroup; Serotyping; Vegetables; Virulence
PubMed: 33341686
DOI: 10.1016/j.ijfoodmicro.2020.109023 -
Microbiology Spectrum Sep 2021Bacteria have necessarily evolved a protective arsenal of proteins to contend with peroxides and other reactive oxygen species generated in aerobic environments....
Bacteria have necessarily evolved a protective arsenal of proteins to contend with peroxides and other reactive oxygen species generated in aerobic environments. Listeria monocytogenes encounters an onslaught of peroxide both in the environment and during infection of the mammalian host, where it is the causative agent of the foodborne illness listeriosis. Despite the importance of peroxide for the immune response to bacterial infection, the strategy by which L. monocytogenes protects against peroxide toxicity has yet to be illuminated. Here, we investigated the expression and essentiality of all the peroxidase-encoding genes during L. monocytogenes growth and during infection of murine cells in tissue culture. We found that and were required for aerobic growth , and and were each required for L. monocytogenes to survive acute peroxide stress. Despite increased expression of , and during infection of macrophages, only proved necessary for cytosolic growth. In contrast, the proteins encoded by , , , , and were dispensable for aerobic growth, acute peroxide detoxification, and infection. Together, our results provide insight into the multifaceted L. monocytogenes peroxide detoxification strategy and demonstrate that L. monocytogenes encodes a functionally diverse set of peroxidase enzymes. Listeria monocytogenes is a facultative intracellular pathogen and the causative agent of the foodborne illness listeriosis. L. monocytogenes must contend with reactive oxygen species generated extracellularly during aerobic growth and intracellularly by the host immune system. However, the mechanisms by which L. monocytogenes defends against peroxide toxicity have not yet been defined. Here, we investigated the roles of each of the peroxidase-encoding genes in L. monocytogenes growth, peroxide stress response, and virulence in mammalian cells.
Topics: Animals; Bacterial Proteins; Disease Models, Animal; Gene Expression Regulation, Bacterial; Listeria monocytogenes; Listeriosis; Macrophages; Mice; Mice, Inbred C57BL; Oxidative Stress; Peroxidases; Virulence; Virulence Factors
PubMed: 34287055
DOI: 10.1128/Spectrum.00440-21 -
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 -
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 -
Foodborne Pathogens and Disease Jun 2024is a critical foodborne pathogen that causes severe invasive and noninvasive diseases and is associated with high mortality. Information on the prevalence of...
is a critical foodborne pathogen that causes severe invasive and noninvasive diseases and is associated with high mortality. Information on the prevalence of infections in Taiwan is very limited. This study aimed to analyze the molecular epidemiological surveillance and virulence gene distribution of 176 human clinical isolates collected between 2009 and 2019 in northern Taiwan. Our results showed that the isolates belonged to 4 serogroups (IIa, IIb, IVb, and IIc), with most isolates in serogroups IIa (81/176, 46%) and IIb (71/176, 40.3%). Multilocus sequence typing analysis revealed 18 sequence types (STs) and 13 clonal complexes (CCs). Eighty-four percent of all isolates belonged to six STs: CC87-ST87 (40/176, 22.7%), CC19-ST378 (36/176, 19.9%), CC155-ST155 (28/176, 15.5%), CC1-ST710 (16/176, 8.8%), CC5-ST5 (16/176, 8.8%), and CC101-ST101 (11/176, 6.1%). Furthermore, our analysis showed the distributions of four pathogenicity islands (LIPI) among all isolates. LIPI-1 and LIPI-2 existed in all isolates, whereas LIPI-3 and LIPI-4 only existed in specific STs and CCs. LIPI-3 existed in the STs, CC1-ST710, CC3-ST3, CC288-ST295, and CC191-ST1458, whereas LIPI-4 could be found in the STs, CC87-ST87 and CC87-ST1459. Strains containing LIPI-3 and LIPI-4 are potentially hypervirulent; thus, 68/176 isolates (39.1%) collected in this study were potentially hypervirulent. Since infections are considered highly correlated with diet, molecular epidemiological surveillance of in food is important; continued surveillance will provide critical information to prevent foodborne diseases.
Topics: Listeria monocytogenes; Taiwan; Humans; Listeriosis; Multilocus Sequence Typing; Virulence; Serogroup; Virulence Factors; Genomic Islands; Foodborne Diseases; Molecular Epidemiology
PubMed: 38346310
DOI: 10.1089/fpd.2023.0136 -
Applied Microbiology and Biotechnology Apr 2018Listeria monocytogenes is a pathogen of significant concern in many ready to eat foods due to its ability to survive and multiply even under significant environmental... (Review)
Review
Listeria monocytogenes is a pathogen of significant concern in many ready to eat foods due to its ability to survive and multiply even under significant environmental stresses. Listeriosis in humans is a concern, especially to high-risk populations such as those who are immunocompromised or pregnant, due to the high rates of morbidity and mortality. Whole genome sequencing has become a routine part of assessing L. monocytogenes isolated from patients, and the frequency of different genetic subtypes associated with listeriosis is now being reported. The recent abundance of genome sequences for L. monocytogenes has provided a wealth of information regarding the variation in core and accessory genomic elements. Newly described accessory genomic regions have been linked to greater virulence capabilities as well as greater resistance to environmental stressors such as sanitizers commonly used in food processing facilities. This review will provide a summary of our current understanding of stress response and virulence phenotypes of L. monocytogenes, within the context of the genetic diversity of the pathogen.
Topics: Food Microbiology; Genetic Variation; Genomics; Humans; Listeria monocytogenes; Listeriosis; Virulence
PubMed: 29500754
DOI: 10.1007/s00253-018-8852-5 -
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 Topics in Microbiology and... 2017Listeria monocytogenes is a ubiquitously occurring gram-positive bacterium in the environment that causes listeriosis, one of the deadliest foodborne infections known... (Review)
Review
Listeria monocytogenes is a ubiquitously occurring gram-positive bacterium in the environment that causes listeriosis, one of the deadliest foodborne infections known today. It is a versatile facultative intracellular pathogen capable of growth within the host's cytosolic compartment. Following entry into the host cell, L. monocytogenes escapes from vacuolar compartments to the cytosol, where the bacterium begins a remarkable journey within the host cytoplasm, culminating in bacterial spread from cell to cell, to deeper tissues and organs. This dissemination process depends on the ability of the bacterium to harness central components of the host cell actin cytoskeleton using the surface bound bacterial factor ActA (actin assembly inducing protein). Hence ActA plays a major role in listerial virulence, and its absence renders bacteria intracellularly immotile and essentially non-infectious. As the bacterium, moving by building a network of filamentous actin behind itself that is often referred to as its actin tail, encounters cell-cell contacts it forms double-vacuolar protrusions that allow it to enter the neighboring cell where the cycle then continues. Recent studies have now implicated ActA in other stages of the life cycle of L. monocytogenes. These include extracellular properties of aggregation and biofilm formation to mediate colonization of the gut lumen, promotion and enhancement of bacterial host cell entry, evasion of autophagy, vacuolar exit, as well as nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB) activation. These novel properties provide a new view of ActA and help explain its role as an essential virulence factor of L. monocytogenes.
Topics: Animals; Bacterial Proteins; Humans; Listeria monocytogenes; Listeriosis; Membrane Proteins; Virulence; Virulence Factors
PubMed: 27726006
DOI: 10.1007/82_2016_30