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FEMS Microbiology Letters Jul 2020Bacterial communication system known as quorum sensing (QS) is a pivotal system for bacterial survival, adaptation and pathogenesis. Members in the multicellular...
Bacterial communication system known as quorum sensing (QS) is a pivotal system for bacterial survival, adaptation and pathogenesis. Members in the multicellular community may synthesize or acquire a signaling molecule in order to elicit downstream cellular processes. Roles of indole and derivatives, a new class of quorum-sensing signal molecules, in various bacterial physiologies and virulence have been reported recently. Indole is normally found in mammal gastrointestinal tract as a metabolite of tryptophan metabolism by microbiota. Therefore, interspecies connection via indole signaling among commensal bacteria and enteric pathogens could be anticipated. Effects of indole exposure on the virulence of Listeria monocytogenes were investigated by phenotypic and molecular approaches. Results demonstrated that synthetic indole and indole-rich conditioned medium significantly diminished biofilm formation and related virulence of L. monocytogenes including motility, cell aggregation and exopolysaccharide production. Transcript levels of virulence-associated (pssE, dltA, flaA, fliI, motB, agrA and hly) and regulatory genes (codY, sigB, prfA and gmaR) were substantially downregulated in indole-treated cells. Only mogR gene encoding for a repressor of motility genes was upregulated after indole exposure. Our findings raise the possibility that L. monocytogenes may acquire indole signaling from gut microbiota for resource-effective adaptation upon transition to new environment.
Topics: Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Humans; Indoles; Listeria monocytogenes; Listeriosis; Quorum Sensing; Virulence
PubMed: 32658271
DOI: 10.1093/femsle/fnaa116 -
Microbiology Spectrum Jul 2019Bacterial metabolism represents the biochemical space that bacteria can manipulate to produce energy, reducing equivalents and building blocks for replication.... (Review)
Review
Bacterial metabolism represents the biochemical space that bacteria can manipulate to produce energy, reducing equivalents and building blocks for replication. Gram-positive pathogens, such as , show remarkable flexibility, which allows for exploitation of diverse biological niches from the soil to the intracytosolic space. Although the human host represents a potentially rich source for nutrient acquisition, competition for nutrients with the host and hostile host defenses can constrain bacterial metabolism by various mechanisms, including nutrient sequestration. Here, we review metabolism in the model Gram-positive bacterium, , and highlight pathways that enable the replication, survival, and virulence of this bacterial pathogen.
Topics: Animals; Bacterial Proteins; Gene Expression Regulation, Bacterial; Humans; Listeria monocytogenes; Listeriosis; Virulence
PubMed: 31418407
DOI: 10.1128/microbiolspec.GPP3-0066-2019 -
Future Microbiology Jun 2017The opportunistic intracellular bacterial pathogen Listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. Research... (Review)
Review
The opportunistic intracellular bacterial pathogen Listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. Research on this bacterium has provided considerable insight into how pathogenic bacteria adapt to mammalian hosts, invade eukaryotic cells, move intracellularly, interfere with host cell functions and disseminate within tissues. It also contributed to unveil features of normal host cell pathways and unsuspected functions of previously known cellular proteins. This review provides an updated overview of our knowledge on this pathogen. In many examples, findings on L. monocytogenes provided the basis for new concepts in bacterial regulation, cell biology and infection processes.
Topics: Actins; Animals; Bacterial Physiological Phenomena; Bacterial Proteins; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; Listeria monocytogenes; Listeriosis; Mice; Microbiota; Peptide Termination Factors; Protein Processing, Post-Translational; Virulence; Virulence Factors
PubMed: 28604108
DOI: 10.2217/fmb-2016-0221 -
Food Microbiology Dec 2017Listeria monocytogenes can cause listeriosis, a severe foodborne disease. In Brazil, despite very few reported cases of listeriosis, the pathogen has been repeatedly...
Listeria monocytogenes can cause listeriosis, a severe foodborne disease. In Brazil, despite very few reported cases of listeriosis, the pathogen has been repeatedly isolated from dairies. This has led the government to implement specific legislation to reduce the hazard. Here, we determined the incidence of L. monocytogenes in five dairies and retail products in the Southeast and Midwest regions of Brazil over eight months. Of 437 samples, three samples (0.7%) from retail and only one sample (0.2%) from the dairies were positive for L. monocytogenes. Thus, the contamination rate was significantly reduced as compared to previous studies. MultiLocus Sequence Typing (MLST) was used to determine if contamination was caused by new or persistent clones leading to the first MLST profile of L. monocytogenes from the Brazilian dairy industry. The processing environment isolate is of concern being a sequence-type (ST) 2, belonging to the lineage I responsible for the majority of listeriosis outbreaks. Also, ST3 and ST8 found in commercialized cheese have previously been reported in outbreaks. Despite the lower incidence, dairy products still pose a potential health risk and the occurrence of L. monocytogenes in dairies and retail products emphasize the need for continuous surveillance of this pathogen in the Brazilian dairy industry.
Topics: Animals; Biodiversity; Brazil; Cattle; Dairy Products; Dairying; Food Contamination; Incidence; Listeria monocytogenes; Listeriosis; Multilocus Sequence Typing
PubMed: 28800821
DOI: 10.1016/j.fm.2017.06.012 -
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,... 2021Listeria monocytogenes is a major food-borne pathogen and causative agent of a fatal disease, listeriosis. Stringent regulatory guidelines and zero tolerance policy...
Listeria monocytogenes is a major food-borne pathogen and causative agent of a fatal disease, listeriosis. Stringent regulatory guidelines and zero tolerance policy toward this bacterium necessitate rapid, accurate, and reliable methods of identification and subtyping. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) has recently become a method of choice for routine identification of pathogens in clinical settings and has largely replaced biochemical assays. Identification relies on well-curated databases such as SARAMIS. Extensive use of SARAMIS to generate consensus mass spectra, in conjunction with statistical analysis, such as partial least square-discriminant analysis and hierarchical cluster analysis, is useful in subtyping bacteria. While MALDI-ToF MS has been extensively used for pathogen detection, its application in bacterial subtyping has been limited. The protocol describes a MALDI-ToF MS workflow as a single tool for simultaneous identification and subtyping of L. monocytogenes directly from solid culture medium.
Topics: Bacterial Typing Techniques; Humans; Listeria monocytogenes; Listeriosis; Software; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Time Factors; Workflow
PubMed: 32975763
DOI: 10.1007/978-1-0716-0982-8_2 -
Journal of Food Science Sep 2020This study was aimed to investigate the presence of Listeria monocytogenes in raw water buffalo milk and milk products, besides determining its serotype and the extent...
This study was aimed to investigate the presence of Listeria monocytogenes in raw water buffalo milk and milk products, besides determining its serotype and the extent of its resistance against various antibiotics. A total of 188 samples of raw water buffalo milk and milk products were collected from Samsun Province, Turkey between November 2012 and May 2013. The classical culture technique was used to isolate and identify L. monocytogenes, as described in EN ISO 11290-1. The isolates were confirmed as L. monocytogenes by using PCR with (hylA) primers specific for the hemolysin gene. The antimicrobial susceptibility test was achieved by using the VITEK 2 compact system and VITEK 2 AST-P640 card. L. monocytogenes was found in 7 (3.7%) of the 188 samples. Four of them were obtained from cheese and three from milk samples. Whereas, L. monocytogenes was not detected in any of the clotted cream samples. A total of 13 isolates were confirmed by PCR as L. monocytogenes. Among these isolates, one was 1/2c (or 3c) (7.6%), three were 4b (or 4d, 4e) (23%), four were 1/2b (or 3b) (30.7%), and the other five isolates were serotype 1/2a (or 3a) (38.4%). The highest antimicrobial resistance was recorded against fosfomycine (100%) followed by oxacillin (92%), penicillin (84%), and erythromycin (69%). However, no resistance was determined against ciprofloxacin, gentamicin, and tigecycline. PRACTICAL APPLICATION: This study showed that some samples of raw buffalo milk and the milk products were contaminated with Listeria monocytogenes. The serotype with the highest prevalence was determined as L. monocytogenes 1/2a. This study also demonstrated that most of the L. monocytogenes isolates had developed multiresistance to many frequently used medical antimicrobial agents.
Topics: Animals; Anti-Bacterial Agents; Buffaloes; Cheese; DNA Primers; Drug Resistance, Bacterial; Food Contamination; Food Microbiology; Listeria monocytogenes; Milk; Polymerase Chain Reaction; Serotyping; Turkey
PubMed: 32794185
DOI: 10.1111/1750-3841.15376 -
Current Opinion in Microbiology Feb 2019Glutathione is a low molecular weight thiol that is important for maintaining intracellular redox homeostasis. Some bacteria are able to import exogenous glutathione as... (Review)
Review
Glutathione is a low molecular weight thiol that is important for maintaining intracellular redox homeostasis. Some bacteria are able to import exogenous glutathione as a nutritional source and to counter oxidative stress. In cytosolic pathogens Burkholderia pseudomallei and Listeria monocytogenes, host glutathione regulates bacterial virulence. In B. pseudomallei, glutathione activates the membrane-bound histidine kinase sensor VirA that leads to activation of the Type VI Secretion System. In L. monocytogenes, host glutathione leads to the binding of bacterial glutathione to the master virulence regulator PrfA as an allosteric activator. Glutathione can also modulate virulence factors to control their activity by S-glutathionylation. Thus, host glutathione acts as a spacio-temporal cue for some pathogens to switch on their virulence programs at the right time and place.
Topics: Burkholderia pseudomallei; Gene Expression Regulation, Bacterial; Glutathione; Host-Pathogen Interactions; Listeria monocytogenes; Virulence
PubMed: 30396015
DOI: 10.1016/j.mib.2018.10.004 -
Colloids and Surfaces. B, Biointerfaces Mar 2019A bacteriophage-assisted magnetic separation method was developed for the isolation of Listeria monocytogenes from complex food matrices. The aim of this study is to...
A bacteriophage-assisted magnetic separation method was developed for the isolation of Listeria monocytogenes from complex food matrices. The aim of this study is to understand the effect of phage immobilization methods and the magnetic particle sizes on the phage coupling and infectivity retention of the magnetic particles. In this study, bacteriophage P100-modified magnetic particles (PMMPs) were developed for the separation of L. monocytogenes from food matrices. Three sizes of magnetic particles (MP) (150 nm, 500 nm, and 1 μm) were used for phage immobilization via chemical and physical methods. The coupling ratio of phage was investigated, and the performance of each PMMP complex was evaluated by their L. monocytogenes capture efficiency. When compared to the chemical immobilization method, the physically immobilized PMMP complex achieved a higher capture efficiency initially, with excellent selectivity towards target bacteria. The PMMPs were further tested for selective isolation of L. monocytogenes using real food samples such as ground beef and whole milk.
Topics: Animals; Bacteriophages; Cattle; Colony Count, Microbial; Food Contamination; Food Microbiology; Food Preservation; Listeria monocytogenes; Magnetics; Milk
PubMed: 30562716
DOI: 10.1016/j.colsurfb.2018.12.007 -
Molecular Microbiology Mar 2020The universe of Molecular Microbial Pathogenesis is filled with many female and male stars. But there are two particularly bright shining supernovae-like stars: the late...
The universe of Molecular Microbial Pathogenesis is filled with many female and male stars. But there are two particularly bright shining supernovae-like stars: the late Stanley Falkow and the very lively and creative Pascale Cossart. These two outstanding luminaries, surrounded by numerous planets, do not only belong to different scientific generations but their splendor also comes from very different scientific concepts. Stanley Falkow, often referred to as the 'Father of Molecular Microbial Pathogenesis', made many groundbreaking contributions to this field by addressing almost all important bacterial pathogens. Pascale Cossart, who could be called in analogy the 'Queen of Modern Molecular Microbial Pathogenesis' by combining the Microbiology and Cell Biology, concentrates in her similarly impressive scientific work essentially on a single bacterial species which she studied and still studies in great depth: the facultative intracellular bacterial pathogen Listeria monocytogenes-and the vast majority of her most prominent publications deals with this pathogen in almost all facets. It is certainly not an exaggeration to say that she together with her co-workers and collaborators developed this model bacterium into a paradigm among the intracellular bacterial pathogens.
Topics: Female; History, 20th Century; History, 21st Century; Host-Pathogen Interactions; Humans; Listeria monocytogenes; Listeriosis; Virulence; Virulence Factors
PubMed: 32185837
DOI: 10.1111/mmi.14450