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Canadian Journal of Veterinary Research... Jan 2023Biofilm (BF) formation is a considerable obstacle to the effective control of (LM). In this study, we used transcriptomics to analyze LM BF and planktonic bacteria at...
Biofilm (BF) formation is a considerable obstacle to the effective control of (LM). In this study, we used transcriptomics to analyze LM BF and planktonic bacteria at different stages of BF formation and growth to compare differential gene expression between the 2. We identified 1588, 1517, and 1462 differentially expressed genes (DEGs) when early formation BF and planktonic bacteria were compared at 12, 24, and 48 h, respectively. Among these, 1123 DEGs were shared across the 3 data pool. Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses demonstrated significant changes associated with the phosphotransferase system, the microbial metabolism in diverse environments, the flagella assembly, the bacterial chemotaxis, the bacterial secretion, the quorum sensing, and the 2-component system. The top 5 upregulated DEGs were , and . The top 5 downregulated DEGs were , and . After real-time quantitative polymerase chain reaction, the expression of these 10 DEGs were consistent with the results of the transcriptomic sequence. This research lays the foundation for further studies on mechanisms regulating BF formation and will help to identify BF inhibitors to reduce the risk of LM infection.
Topics: Animals; Listeria monocytogenes; Transcriptome; Biofilms
PubMed: 36606039
DOI: No ID Found -
BioMed Research International 2015Listeriolysin O (LLO) is a thiol-activated cholesterol-dependent pore-forming toxin and the major virulence factor of Listeria monocytogenes (LM). Extensive research in... (Review)
Review
Listeriolysin O (LLO) is a thiol-activated cholesterol-dependent pore-forming toxin and the major virulence factor of Listeria monocytogenes (LM). Extensive research in recent years has revealed that LLO exerts a wide array of biological activities, during the infection by LM or by itself as recombinant antigen. The spectrum of biological activities induced by LLO includes cytotoxicity, apoptosis induction, endoplasmic reticulum stress response, modulation of gene expression, intracellular calcium oscillations, and proinflammatory activity. In addition, LLO is a highly immunogenic toxin and the major target for innate and adaptive immune responses in different animal models and humans. Recently, the crystal structure of LLO has been published in detail. Here, we review the structure-function relationship for this fascinating microbial molecule, highlighting the potential uses of LLO in the fields of biomedicine and biotechnology, particularly in vaccination.
Topics: Animals; Bacterial Toxins; Heat-Shock Proteins; Hemolysin Proteins; Humans; Listeria monocytogenes; Protein Structure, Tertiary; Structure-Activity Relationship; Vaccination
PubMed: 25874208
DOI: 10.1155/2015/360741 -
Microbial Biotechnology May 2020Listeria monocytogenes is the causative agent of the foodborne illness listeriosis, which can result in severe symptoms and death in susceptible humans and other...
Listeria monocytogenes is the causative agent of the foodborne illness listeriosis, which can result in severe symptoms and death in susceptible humans and other animals. L. monocytogenes is ubiquitous in the environment and isolates from food and food processing, and clinical sources have been extensively characterized. However, limited information is available on L. monocytogenes from wildlife, especially from urban or suburban settings. As urban and suburban areas are expanding worldwide, humans are increasingly encroaching into wildlife habitats, enhancing the frequency of human-wildlife contacts and associated pathogen transfer events. We investigated the prevalence and characteristics of L. monocytogenes in 231 wild black bear capture events between 2014 and 2017 in urban and suburban sites in North Carolina, Georgia, Virginia and United States, with samples derived from 183 different bears. Of the 231 captures, 105 (45%) yielded L. monocytogenes either alone or together with other Listeria. Analysis of 501 samples, primarily faeces, rectal and nasal swabs for Listeria spp., yielded 777 isolates, of which 537 (70%) were L. monocytogenes. Most L. monocytogenes isolates exhibited serotypes commonly associated with human disease: serotype 1/2a or 3a (57%), followed by the serotype 4b complex (33%). Interestingly, approximately 50% of the serotype 4b isolates had the IVb-v1 profile, associated with emerging clones of L. monocytogenes. Thus, black bears may serve as novel vehicles for L. monocytogenes, including potentially emerging clones. Our results have significant public health implications as they suggest that the ursine host may preferentially select for L. monocytogenes of clinically relevant lineages over the diverse listerial populations in the environment. These findings also help to elucidate the ecology of L. monocytogenes and highlight the public health significance of the human-wildlife interface.
Topics: Animals; Animals, Wild; Listeria monocytogenes; Listeriosis; Southeastern United States; Ursidae
PubMed: 31713354
DOI: 10.1111/1751-7915.13509 -
BMC Microbiology May 2020Listeria monocytogenes (L. monocytogenes) is a global opportunistic intracellular pathogen that can cause many infections, including meningitis and abortion in humans...
BACKGROUND
Listeria monocytogenes (L. monocytogenes) is a global opportunistic intracellular pathogen that can cause many infections, including meningitis and abortion in humans and animals; thus, L. monocytogenes poses a great threat to public safety and the development of the aquaculture industry. The isolation rate of Listeria monocytogenes in fishery products has always been high. And the pore-forming toxin listeriolysin O (LLO) is one of the most important virulence factors of L. monocytogenes. LLO can promote cytosolic bacterial proliferation and help the pathogen evade attacks from the host immune system. In addition, L. monocytogenes infection can trigger a series of severe inflammatory reactions.
RESULTS
Here, we further confirmed that morin lacking anti-Listeria activity could inhibit LLO oligomerization. We also found that morin can effectively alleviate the inflammation induced by Listeria in vivo and in vitro and exerted an obvious protective effect on infected cells and mice.
CONCLUSIONS
Morin does not possess anti-Listeria activity, neither does it interfere with secretion of LLO. However, morin inhibits oligomerisation of LLO and morin does reduce the inflammation caused during Listeria infection.
Topics: Animals; Bacterial Toxins; Cell Line; Disease Models, Animal; Flavonoids; Gene Expression Regulation, Bacterial; Heat-Shock Proteins; Hemolysin Proteins; Humans; Listeria monocytogenes; Listeriosis; Mice; Protein Multimerization; Virulence
PubMed: 32398085
DOI: 10.1186/s12866-020-01807-6 -
Methods in Molecular Biology (Clifton,... 2017Listeria monocytogenes is a bacterial pathogen which invades and multiplies within non-professional phagocytes. Signaling cascades involved in cellular entry have been...
Listeria monocytogenes is a bacterial pathogen which invades and multiplies within non-professional phagocytes. Signaling cascades involved in cellular entry have been extensively analyzed, but the events leading to vacuolar escape remain less clear. In this chapter, we detail a microscopy FRET-based assay which allows quantitatively measuring L. monocytogenes infection and escape from its internalization vacuole, as well as a correlative light/electron microscopy method to investigate the morphological features of the vacuolar compartments containing L. monocytogenes.
Topics: Biological Transport; Fluorescence Resonance Energy Transfer; Listeria monocytogenes; Microscopy, Electron; Microscopy, Fluorescence; Vacuoles
PubMed: 27914079
DOI: 10.1007/978-1-4939-6673-8_11 -
MBio Apr 2018The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to...
The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination. Here, complete VBNC induction of green fluorescent protein-tagged and serovar Thompson was achieved by exposure to 12 and 3 ppm chlorine, respectively. The pathogens were subjected to chlorine washing following incubation on spinach leaves. Culture data revealed that total viable and Thompson populations became VBNC by 50 and 100 ppm chlorine, respectively, while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability. The pathogenicity of chlorine-induced VBNC and Thompson was assessed by using Ingestion of VBNC pathogens by resulted in a significant life span reduction ( = 0.0064 and < 0.0001), and no significant difference between the life span reductions caused by the VBNC and culturable treatments was observed. was visualized beyond the nematode intestinal lumen, indicating resuscitation and cell invasion. These data emphasize the risk that VBNC food-borne pathogens could pose to public health should they continue to go undetected. Many bacteria are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses. VBNC cells cannot be detected by standard laboratory culture techniques, presenting a problem for the food industry, which uses these techniques to detect pathogen contaminants. This study found that chlorine, a sanitizer commonly used for fresh produce, induces a VBNC state in the food-borne pathogens and It was also found that chlorine is ineffective at killing total populations of the pathogens. A life span reduction was observed in that ingested these VBNC pathogens, with VBNC as infectious as its culturable counterpart. These data show that VBNC food-borne pathogens can both be generated and avoid detection by industrial practices while potentially retaining the ability to cause disease.
Topics: Animals; Anti-Infective Agents; Caenorhabditis elegans; Chlorine; Disease Models, Animal; Listeria monocytogenes; Listeriosis; Microbial Viability; Salmonella Infections; Salmonella enterica; Spinacia oleracea; Survival Analysis; Virulence
PubMed: 29666286
DOI: 10.1128/mBio.00540-18 -
Clinical Microbiology and Infection :... Apr 2017Listeria monocytogenes is a food-borne pathogen that can cause meningitis. The listerial genotype ST6 has been linked to increasing rates of unfavourable outcome over...
OBJECTIVES
Listeria monocytogenes is a food-borne pathogen that can cause meningitis. The listerial genotype ST6 has been linked to increasing rates of unfavourable outcome over time. We investigated listerial genetic variation and the relation with clinical outcome in meningitis.
METHODS
We sequenced 96 isolates from adults with listerial meningitis included in two prospective nationwide cohort studies by whole genome sequencing, and evaluated associations between bacterial genetic variation and clinical outcome. We validated these results by screening listerial genotypes of 445 cerebrospinal fluid and blood isolates from patients over a 30-year period from the Dutch national surveillance cohort.
RESULTS
We identified a bacteriophage, phiLMST6 co-occurring with a novel plasmid, pLMST6, in ST6 isolates to be associated with unfavourable outcome in patients (p 2.83e-05). The plasmid carries a benzalkonium chloride tolerance gene, emrC, conferring decreased susceptibility to disinfectants used in the food-processing industry. Isolates harbouring emrC were growth inhibited at higher levels of benzalkonium chloride (median 60 mg/L versus 15 mg/L; p <0.001), and had higher MICs for amoxicillin and gentamicin compared with isolates without emrC (both p <0.001). Transformation of pLMST6 into naive strains led to benzalkonium chloride tolerance and higher MICs for gentamicin.
CONCLUSIONS
These results show that a novel plasmid, carrying the efflux transporter emrC, is associated with increased incidence of ST6 listerial meningitis in the Netherlands. Suggesting increased disease severity, our findings warrant consideration of disinfectants used in the food-processing industry that select for resistance mechanisms and may, inadvertently, lead to increased risk of poor disease outcome.
Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Anti-Infective Agents, Local; Benzalkonium Compounds; Cohort Studies; Drug Resistance, Bacterial; Female; Genetic Variation; Genome, Bacterial; High-Throughput Nucleotide Sequencing; Humans; Listeria monocytogenes; Male; Meningitis, Listeria; Middle Aged; Netherlands; Patient Outcome Assessment; Phylogeny; Plasmids; Polymorphism, Single Nucleotide; Population Surveillance; Young Adult
PubMed: 27998823
DOI: 10.1016/j.cmi.2016.12.008 -
Applied and Environmental Microbiology Mar 2017is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to...
is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables to tolerate exposure to cadmium is the efflux system, with CadA being a P-type ATPase. Three different genes (designated to ) were previously characterized in A novel putative cadmium resistance gene () was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking. In this study, we characterized in strain F8027, a cadmium-resistant strain of serotype 4b. By screening a mariner-based transposon library of this strain, we identified a mutant with reduced tolerance to cadmium and that harbored a single transposon insertion in The tolerance to cadmium was restored by genetic complementation with the cadmium resistance cassette (), and enhanced cadmium tolerance was conferred to two unrelated cadmium-sensitive strains via heterologous complementation with Cadmium exposure induced expression, even at noninhibitory levels. Virulence assessments in the model suggested that a functional suppressed virulence, potentially promoting commensal colonization of the insect larvae. Biofilm assays suggested that inactivation reduced biofilm formation. These data not only confirm as a novel cadmium resistance determinant in but also provide evidence for roles in virulence and biofilm formation. is an intracellular foodborne pathogen causing the disease listeriosis, which is responsible for numerous hospitalizations and deaths every year. Among the adaptations that enable the survival of in the environment are the abilities to persist in biofilms, grow in the cold, and tolerate toxic compounds, such as heavy metals. Here, we characterized a novel determinant that was recently identified on a larger mobile genetic island through whole-genome sequencing. This gene () was found to be responsible for cadmium detoxification and to be a divergent member of the Cad family of cadmium efflux pumps. Virulence assessments in a model suggested that may suppress virulence. Additionally, may be involved in the ability of to form biofilms. Beyond the role in cadmium detoxification, the involvement of in other cellular functions potentially explains its retention and wide distribution in .
Topics: Animals; Bacterial Proteins; Biofilms; Cadmium; DNA Transposable Elements; Disease Models, Animal; Drug Resistance, Bacterial; Food Microbiology; Gene Expression Regulation, Bacterial; Genes, Bacterial; Larva; Lepidoptera; Listeria monocytogenes; Listeriosis; Metals, Heavy; Microbial Sensitivity Tests; Mutagenesis, Site-Directed; Sequence Alignment; Virulence
PubMed: 27986731
DOI: 10.1128/AEM.02580-16 -
Journal of Dairy Science Mar 2020Dairy product safety is a global public health issue that demands new approaches and technologies to control foodborne pathogenic microorganisms. Natural antimicrobial... (Review)
Review
Dairy product safety is a global public health issue that demands new approaches and technologies to control foodborne pathogenic microorganisms. Natural antimicrobial agents such as nisin can be added to control the growth of pathogens of concern in dairy foods, namely Listeria monocytogenes and Staphylococcus aureus. However, several factors affect the antimicrobial efficacy of nisin when directly added into the food matrix such as lack of stability at neutral pH, interaction with fat globules, casein, and divalent cations. To overcome these limitations, new and advanced strategies are discussed including nisin encapsulation technology, addition to active packaging, bioengineering, and combination with other antimicrobials. This review highlights advanced technologies with potential to expand and improve the use of nisin as a dairy preservative.
Topics: Anti-Bacterial Agents; Dairy Products; Food Microbiology; Food Preservation; Food Preservatives; Listeria monocytogenes; Nisin; Staphylococcus aureus
PubMed: 31928749
DOI: 10.3168/jds.2019-17498 -
Infection and Immunity Apr 2019is considered a nonpathogenic species. Natural atypical hemolytic isolates have been reported but have not been characterized in detail. Here, we report the genomic... (Comparative Study)
Comparative Study
is considered a nonpathogenic species. Natural atypical hemolytic isolates have been reported but have not been characterized in detail. Here, we report the genomic and functional characterization of representative isolates from the two known natural hemolytic clades. Whole-genome sequencing confirmed the presence of pathogenicity islands (LIPI) characteristic of species. Functional assays showed that LIPI-1 and genes are transcribed, and the corresponding gene products are expressed and functional. Using and assays, we show that atypical hemolytic is virulent, can actively cross the intestinal epithelium, and spreads systemically to the liver and spleen, albeit to a lesser degree than the reference EGDe strain. Although human exposure to hemolytic is likely rare, these findings are important for food safety and public health. The presence of virulence traits in some clades supports the existence of a common virulent ancestor of and .
Topics: Animals; Bacterial Proteins; Bird Diseases; Ducks; Feces; Galliformes; Genome, Bacterial; Genomic Islands; Humans; Listeria; Listeria monocytogenes; Listeriosis; Phylogeny; Serotyping; Virulence; Whole Genome Sequencing
PubMed: 30670551
DOI: 10.1128/IAI.00758-18