scholarly journals Use of multi-locus sequencing typing as identification method for the food-borne pathogen Listeria monocytogenes: a review

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Sonia Lamon ◽  
Domenico Meloni ◽  
Simonetta Gianna Consolati ◽  
Anna Mureddu ◽  
Rina Mazzette
Keyword(s):  
Listeria Monocytogenes ◽  
Detection Methods ◽  
Causative Organism ◽  
Intracellular Pathogen ◽  
Bacterial Strains ◽  
New Approach ◽  
Food Borne ◽  
Global Epidemiology ◽  
Selection Of

<em>Listeria monocytogenes</em> is an ubiquitous, intracellular pathogen which has been implicated within the past decade as the causative organism in several outbreaks of foodborne diseases. In this review, a new approach to molecular typing primarily designed for global epidemiology has been described: multi-<em>locus</em> sequencing typing (MLST). This approach is novel, in that it uses data that allow the unambiguous characterization of bacterial strains via the Internet. Our aim is to present the currently available selection of references on <em>L. monocytogenes</em> MLST detection methods and to discuss its use as <em>gold</em> <em>standard</em> to <em>L. monocytogenes</em> subtyping method.

scholarly journals A Rapid and Sensitive Europium Nanoparticle-Based Lateral Flow Immunoassay Combined with Recombinase Polymerase Amplification for Simultaneous Detection of Three Food-Borne Pathogens

2021 ◽  
Vol 18 (9) ◽  
pp. 4574
Author(s):  
Kai Chen ◽  
Biao Ma ◽  
Jiali Li ◽  
Erjing Chen ◽  
Ying Xu ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Simultaneous Detection ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Quantitative Detection ◽  
Bacterial Strains ◽  
Food Borne Pathogens ◽  
Food Borne

Food-borne pathogens have become an important public threat to human health. There are many kinds of pathogenic bacteria in food consumed daily. A rapid and sensitive testing method for multiple food-borne pathogens is essential. Europium nanoparticles (EuNPs) are used as fluorescent probes in lateral flow immunoassays (LFIAs) to improve sensitivity. Here, recombinase polymerase amplification (RPA) combined with fluorescent LFIA was established for the simultaneous and quantitative detection of Listeria monocytogenes, Vibrio parahaemolyticus, and Escherichia coliO157:H7. In this work, the entire experimental process could be completed in 20 min at 37 °C. The limits of detection (LODs) of EuNP-based LFIA–RPA were 9.0 colony-forming units (CFU)/mL for Listeria monocytogenes, 7.0 CFU/mL for Vibrio parahaemolyticus, and 4.0 CFU/mL for Escherichia coliO157:H7. No cross-reaction could be observed in 22 bacterial strains. The fluorescent LFIA–RPA assay exhibits high sensitivity and good specificity. Moreover, the average recovery of the three food-borne pathogens spiked in food samples was 90.9–114.2%. The experiments indicate the accuracy and reliability of the multiple fluorescent test strips. Our developed EuNP-based LFIA–RPA assay is a promising analytical tool for the rapid and simultaneous detection of multiple low concentrations of food-borne pathogens.

scholarly journals Identification and Characterization of Di- and Tripeptide Transporter DtpT of Listeria monocytogenes EGD-e

2005 ◽  
Vol 71 (10) ◽  
pp. 5771-5778 ◽  
Author(s):  
Jeroen A. Wouters ◽  
Torsten Hain ◽  
Ajub Darji ◽  
Eric Hüfner ◽  
Henrike Wemekamp-Kamphuis ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Opportunistic Infections ◽  
Essential Amino Acids ◽  
Defined Medium ◽  
Infection Model ◽  
Intracellular Pathogen ◽  
Mouse Infection Model ◽  
Stress Protection ◽  
Identification And Characterization

ABSTRACT Listeria monocytogenes is a gram-positive intracellular pathogen responsible for opportunistic infections in humans and animals. Here we identified and characterized the dtpT gene (lmo0555) of L. monocytogenes EGD-e, encoding the di- and tripeptide transporter, and assessed its role in growth under various environmental conditions as well as in the virulence of L. monocytogenes. Uptake of the dipeptide Pro-[14C]Ala was mediated by the DtpT transporter and was abrogated in a ΔdtpT isogenic deletion mutant. The DtpT transporter was shown to be required for growth when the essential amino acids leucine and valine were supplied as peptides. The protective effect of glycine- and proline-containing peptides during growth in defined medium containing 3% NaCl was noted only in L. monocytogenes EGD-e, not in the ΔdtpT mutant strain, indicating that the DtpT transporter is involved in salt stress protection. Infection studies showed that DtpT contributes to pathogenesis in a mouse infection model but has no role in bacterial growth following infection of J774 macrophages. These studies reveal that DptT may contribute to the virulence of L. monocytogenes.

scholarly journals Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes

2021 ◽  
Vol 17 (8) ◽  
pp. e1009819
Author(s):  
Andrea Anaya-Sanchez ◽  
Ying Feng ◽  
John C. Berude ◽  
Daniel A. Portnoy
Keyword(s):  
Listeria Monocytogenes ◽  
Transcriptional Activation ◽  
Protein Glycation ◽  
Host Cells ◽  
Intracellular Pathogen ◽  
Cell Monolayers ◽  
Food Borne ◽  
Virulence Regulator ◽  
Allosteric Activator

Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA.

scholarly journals Lactoferrin Functionalized Biomaterials: Tools for Prevention of Implant-Associated Infections

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 522
Author(s):  
Emoke Pall ◽  
Alexandra Roman
Keyword(s):  
Tissue Engineering ◽  
Antimicrobial Peptide ◽  
Multidrug Resistant ◽  
Orthopedic Implant ◽  
Bacterial Strains ◽  
New Approach ◽  
Biomedical Field ◽  
Proper Material ◽  
Selection Of ◽  
Scientific Engineering

Tissue engineering is one of the most important biotechnologies in the biomedical field. It requires the application of the principles of scientific engineering in order to design and build natural or synthetic biomaterials feasible for the maintenance of tissues and organs. Depending on the specific applications, the selection of the proper material remains a significant clinical concern. Implant-associated infection is one of the most severe complications in orthopedic implant surgeries. The treatment of these infections is difficult because the surface of the implant serves not only as a substrate for the formation of the biofilm, but also for the selection of multidrug-resistant bacterial strains. Therefore, a promising new approach for prevention of implant-related infection involves development of new implantable, non-antibiotic-based biomaterials. This review provides a brief overview of antimicrobial peptide-based biomaterials—especially those coated with lactoferrin.

scholarly journals Characterization of the Bifunctional Glycosyltransferase/Acyltransferase Penicillin-Binding Protein 4 of Listeria monocytogenes

2006 ◽  
Vol 188 (5) ◽  
pp. 1875-1881 ◽  
Author(s):  
Joanna Zawadzka-Skomiał ◽  
Zdzislaw Markiewicz ◽  
Martine Nguyen-Distèche ◽  
Bart Devreese ◽  
Jean-Marie Frère ◽  
...  
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Chain Elongation ◽  
Lipid Ii ◽  
Food Borne ◽  
Glycan Chain ◽  
Chain Polymerization ◽  
Hydrolysis Of

ABSTRACT Multimodular penicillin-binding proteins (PBPs) are essential enzymes responsible for bacterial cell wall peptidoglycan (PG) assembly. Their glycosyltransferase activity catalyzes glycan chain elongation from lipid II substrate (undecaprenyl-pyrophosphoryl-N-acetylglucosamine-N-acetylmuramic acid-pentapeptide), and their transpeptidase activity catalyzes cross-linking between peptides carried by two adjacent glycan chains. Listeria monocytogenes is a food-borne pathogen which exerts its virulence through secreted and cell wall PG-associated virulence factors. This bacterium has five PBPs, including two bifunctional glycosyltransferase/transpeptidase class A PBPs, namely, PBP1 and PBP4. We have expressed and purified the latter and have shown that it binds penicillin and catalyzes in vitro glycan chain polymerization with an efficiency of 1,400 M−1 s−1 from Escherichia coli lipid II substrate. PBP4 also catalyzes the aminolysis (d-Ala as acceptor) and hydrolysis of the thiolester donor substrate benzoyl-Gly-thioglycolate, indicating that PBP4 possesses both transpeptidase and carboxypeptidase activities. Disruption of the gene lmo2229 encoding PBP4 in L. monocytogenes EGD did not have any significant effect on growth rate, peptidoglycan composition, cell morphology, or sensitivity to β-lactam antibiotics but did increase the resistance of the mutant to moenomycin.

scholarly journals An Improved Cloning Vector for Construction of Gene Replacements in Listeria monocytogenes

2003 ◽  
Vol 69 (5) ◽  
pp. 3020-3023 ◽  
Author(s):  
Guojie Li ◽  
S. Kathariou
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Plasmid Vector ◽  
Gene Replacement ◽  
Direct Selection ◽  
Genetic Studies ◽  
Food Borne ◽  
Food Borne Illness ◽  
Selection For ◽  
Selection Of

ABSTRACT Listeria monocytogenes is a gram-positive, facultative intracellular bacterium implicated in severe food-borne illness (listeriosis) in humans. The construction of well-defined gene replacements in the genome of L. monocytogenes has been instrumental to several genetic studies of the virulence and other attributes of the organism. Construction of such mutations by currently available procedures, however, tends to be labor intensive, and gene replacement mutants are sometimes difficult to recover due to lack of direct selection for the construct. In this study we describe the construction and use of plasmid vector pGF-EM, which can be conjugatively transferred from Escherichia coli S17-1 to L. monocytogenes and which provides the genetic means for direct selection of gene replacements.

scholarly journals DNAFoil, a novel technology for the rapid detection of food pathogens: Preliminary validation on Salmonella and Listeria monocytogenes

2021 ◽  
Vol 33 (SP1) ◽  
pp. 43-54
Author(s):  
Aly El Sheikha
Keyword(s):  
Quality Control ◽  
Listeria Monocytogenes ◽  
Pathogen Detection ◽  
Food Contamination ◽  
Detection Methods ◽  
Bacterial Strains ◽  
Lateral Flow Strip ◽  
Dna Test ◽  
Food Pathogens ◽  
Food Pathogen

Over the past decades, several tools have been developed for food pathogen detection, including proteomics, metabolomics, immunological, biosensor, and nucleic acid-based approaches. Although these techniques are reliable and precise, they are time-consuming, technically challenging, and costly. Hence, it is necessary to develop rapid techniques for food pathogen detection, which can be performed at the household level. DNAFoil mechanism is a portable, completely self-administered, on-site DNA test that does not need expensive instru-ments or settings to confirm food pathogen detection in as little as 30 min. DNAFoil was used successfully for detecting food contamination and adulteration with pork derivatives (down to 0.1%) and vegetal components (down to 0.01%), respectively. In this study, initial validation experiments of DNAFoil were investigated to detect Listeria monocytogenes and Salmonella contamination. To confirm the specificity of the proposed method toward Salmonella, 18 different Salmonella strains, 6 non-Salmonella bacteria, and 2 fungi were investigated; also, in the case of Listeria monocytogenes, five bacterial strains, two fungi, and Listeria monocytogenes were investigated. The results stated that the Swiss Decode Salmonella and L. monocytogenes solutions can detect as few as 1 and 10 copies of DNA per microliter, respectively. The results also showed that the accuracy of our method ranges between 92 and 100%, while the precision value ranged between 88 and 100%. In terms of quality control applicability, DNAFoil Salmonella and Listeria monocytogenes reactions could be visually detected with the naked eye using a lateral flow strip, which could be used for in-place quality control during manufacturing and also can be used for more lab tests. In terms of cost, DNAFoil is usually much cheaper than the traditional detection methods. Therefore, DNAFoil is proposed as a promising and universal detection technology for food pathogens.

scholarly journals A Putative ABC Transporter Is Involved in Negative Regulation of Biofilm Formation by Listeria monocytogenes

2008 ◽  
Vol 74 (24) ◽  
pp. 7675-7683 ◽  
Author(s):  
Xinna Zhu ◽  
Fei Long ◽  
Yonghui Chen ◽  
Susanne Knøchel ◽  
Qunxin She ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Abc Transporter ◽  
Biofilm Formation ◽  
Negative Regulation ◽  
Atp Binding ◽  
Coding Region ◽  
Gene Encoding ◽  
Food Borne ◽  
Atp Binding Protein

ABSTRACT Listeria monocytogenes may persist for long periods in food processing environments. In some instances, this may be due to aggregation or biofilm formation. To investigate the mechanism controlling biofilm formation in the food-borne pathogen L. monocytogenes, we characterized LM-49, a mutant with enhanced ability of biofilm formation generated via transposon Tn917 mutagenesis of L. monocytogenes 4b G. In this mutant, a Tn917 insertion has disrupted the coding region of the gene encoding a putative ATP-binding cassette (ABC) transporter permease identical to Lmof2365_1771 (a putative ABC transporter permease) presented in the sequenced strain L. monocytogenes strain 4b F2365. This disrupted gene, denoted lm.G_1771, encoded a protein with 10 transmembrane helixes. The revertant, LM-49RE, was obtained by replacing lm.G_1771::Tn917 with lm.G_1771 via homologous recombination. We found that LM-49RE formed the same amount of biofilm biomass as the wild-type strain. Furthermore, transcription of the downstream lm.G_1770 gene was not influenced by the upstream Tn917 insertion, and the presence of Tn917 has no effect on biofilm formation. These results suggest that lm.G_1771 was solely responsible for the negative regulation of biofilm formation by L. monocytogenes 4b G. The immediate gene upstream of lm.G_1771 encoded an ATP-binding protein. Bioinformatics analysis suggested that these two genes were organized into an operon and that their proteins formed an export ABC transporter. Here, we report the characterization of the mutant and identification of a novel ABC transporter that functions in negative regulation of biofilm formation in L. monocytogenes.

scholarly journals Isolation and characterization of infectious Vibrio parahaemolyticus, the causative agent of AHPND, from the whiteleg shrimp (Litopenaeus vannamei)

2017 ◽  
Vol 44 (3) ◽  
pp. 470-479
Author(s):  
Patricia López-León ◽  
Antonio Luna-González ◽  
Ruth Escamilla-Montes ◽  
María del Carmen Flores-Miranda ◽  
Jesús A. Fierro-Coronado ◽  
...  
Keyword(s):  
Causative Agent ◽  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Bacterial Strains ◽  
Isolation And Characterization ◽  
Commercial Farms ◽  
Whiteleg Shrimp ◽  
Acute Hepatopancreatic Necrosis Disease ◽  
Selection Of

Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND), was isolated from the hepatopancreas of moribund whiteleg shrimp of commercial farms from Guasave, Sinaloa, Mexico. The isolates were screened on thiosulfate citrate bile salt sucrose agar plates for the selection of green colonies and further characterized through PCR with AP3 primers, 89F/R primers, hemolysin genes, hemolytic and enzymatic activity, hydrophobicity, autoaggregation, and biofilm formation. Bioassays by immersion challenge were conducted to confirm the pathogenicity of selected bacterial strains. In addition, the LC50 was calculated for each isolate. All isolates (35) belonged to V. parahaemolyticus, but three isolates did not correspond to strains that cause AHPND since they were negative with 89F/R primers. All isolates were αhemolytic and showed biofilm formation (from moderate to strong). Isolates were hydrophobic or hydrophilic and showed high autoaggregation capacity. Eight strains did not kill shrimp and eleven were pathogenic, but differences in virulence were found among them perhaps due to α-hemolysis and differences in biofilm formation and hydrophobicity. Therefore, performed characterization may help to understand the pathogenicity of V. parahaemolyticus. Finally, results showed that smaller shrimp are less resistant to V. parahaemolyticus infection.

scholarly journals Pathogens Contamination Level Reduction on Beef Using Organic Acids Decontamination Methods

2017 ◽  
Vol 74 (2) ◽  
pp. 212 ◽  
Author(s):  
Sorin Daniel DAN ◽  
Marian MIHAIU ◽  
Oana REGET ◽  
Delia OLTEAN ◽  
Alexandra TĂBĂRAN
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Citric Acid ◽  
Organic Acids ◽  
Salmonella Enteritidis ◽  
Contamination Level ◽  
Bacterial Strains ◽  
Food Borne ◽  
Food Borne Illness ◽  
Level Reduction

In this study we aimed to assess the efficiency of organic acids in different concentrations regarding pathogens as Salmonella, Listeria and Escherichia on beef, which can cause food borne illness in humans. The samples were sterilized using UV radiation for 30 minutes, afterwards being contaminated with 1 ml of microbial suspension (0.5 MacFarland). We used reference bacterial strains for Salmonella Enteritidis, Escherichia coli and Listeria monocytogenes. The samples were subjected to decontamination procedure by introducing 25mL of solution of lactic, acetic or citric acid in concentration of 1%, 2% and 3%. The results showed a reduction of initial pathogen load, ranging from 0.32 to 7.78 log CFU/g, depending on the type of acid, concentration and pathogen sensitivity. After decontamination, standardized methods have been used for the isolation of pathogenic germs. Based on statistical analysis we conclude that pathogens have a different sensitivity to the action of acid solutions, their sensitivity in ascending order being: Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli. Among the organic acids, the most efficient was lactic acid, followed by acetic acid and less efficient citric acid. The greatest reduction of germs was determined by the concentration of 3%.

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