scholarly journals Physical and antibiotic stresses require activation of the RsbU phosphatase to induce the general stress response in Listeria monocytogenes

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2660-2669 ◽  
Author(s):  
Ji-Hyun Shin ◽  
Margaret S. Brody ◽  
Chester W. Price
Keyword(s):  
Listeria Monocytogenes ◽  
Protein Interactions ◽  
Single Copy ◽  
Nutritional Stress ◽  
Serine Phosphorylation ◽  
Intestinal Lumen ◽  
Food Borne ◽  
Multiple Challenges ◽  
Stress Signals ◽  
Food Borne Infections

Among pathogenic strains of Listeria monocytogenes, the σ B transcription factor has a pivotal role in the outcome of food-borne infections. This factor is activated by diverse stresses to provide general protection against multiple challenges, including those encountered during gastrointestinal passage. It also acts with the PrfA regulator to control virulence genes needed for entry into intestinal lumen cells. Environmental and nutritional signals modulate σ B activity via a network that operates by the partner switching mechanism, in which protein interactions are controlled by serine phosphorylation. This network is well characterized in the related bacterium Bacillus subtilis. A key difference in Listeria is the presence of only one input phosphatase, RsbU, instead of the two found in B. subtilis. Here, we aim to determine whether this sole phosphatase is required to convey physical, antibiotic and nutritional stress signals, or if additional pathways might exist. To that end, we constructed L. monocytogenes 10403S strains bearing single-copy, σ B-dependent opuCA–lacZ reporter fusions to determine the effects of an rsbU deletion under physiological conditions. All stresses tested, including acid, antibiotic, cold, ethanol, heat, osmotic and nutritional challenge, required RsbU to activate σ B. This was of particular significance for cold stress activation, which occurs via a phosphatase-independent mechanism in B. subtilis. We also assayed the effects of the D80N substitution in the upstream RsbT regulator that activates RsbU. The mutant had a phenotype consistent with low and uninducible phosphatase activity, but nonetheless responded to nutritional stress. We infer that RsbU activity but not its induction is required for nutritional signalling, which would enter the network downstream from RsbU.

scholarly journals Distribution of serotypes of Listeria monocytogenes in chicken meats in Turkey

2020 ◽  
Vol 70 (4) ◽  
pp. 1859
Author(s):  
S. SAHIN ◽  
R. KALIN ◽  
MN MOGULKOC
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Large Scale ◽  
Meat Products ◽  
Health Problems ◽  
Chicken Meat ◽  
Serotype Distribution ◽  
Food Borne ◽  
Serotype 1 ◽  
Food Borne Infections

Listeria monocytogenes is one of the important causes of food-borne infections. This study was conducted to determine the presence of L. monocytogenes and its serotype distribution in a total of 400 packaged chicken meat products (drumstick, breast, wing, and whole chicken) from different national companies. L. monocytogenes contamination was detected in 26.5% (106 in 400) of all samples when the products considered, drumsticks, breasts, wings, and whole chickens showed 47%, 15%, 35, and 9% positivity respectively. Four important serotypes of L. monocytogenes in human listeriosis (1/2a, 1/2b, 1/2c and 4b) were identified, and serotype 1/2a (94.3%) was determined as predominant in packaged chicken meats. The present study revealed that L. monocytogenes 1/2a serotype is prevalent in chicken meats and this may cause public health problems in Turkey. Further studies in poultry meats should be conducted on a large scale such as regional or national big markets to determine the presence of the pathogen and its dominant serotypes.

scholarly journals Quantifying Translocation of Listeria monocytogenes in Rats by Using Urinary Nitric Oxide-Derived Metabolites

2000 ◽  
Vol 66 (12) ◽  
pp. 5301-5305 ◽  
Author(s):  
R. Corinne Sprong ◽  
Marco F. E. Hulstein ◽  
Roelof van der Meer
Keyword(s):  
Nitric Oxide ◽  
Listeria Monocytogenes ◽  
Intestinal Lumen ◽  
Dependent Manner ◽  
Mesenteric Lymph Nodes ◽  
Food Borne ◽  
Noninvasive Biomarker ◽  
Nitric Oxide Metabolites ◽  
Dose Dependent Increase ◽  
Dose Dependent

ABSTRACT The urinary nitric oxide metabolites NO2 −and NO3 − (summed as NOx) are a noninvasive, quantitative biomarker of translocation of salmonella from the intestinal lumen to systemic organs. Listeria monocytogenes is a food-borne gram-positive pathogen that can also cross the intestinal epithelium. In this study, we tested the efficacy of urinary NOx as a marker of listeria translocation. Rats (eight per group) were orally infected with increasing doses of L. monocytogenes; control rats received heat-killed listeria. The kinetics of urinary NOx and population levels of listeria in feces were determined for 7 days. Another group of rats was killed 1 day after infection to verify translocation by culturing viable listeria from systemic organs. Oral administration of increasing doses of L. monocytogenesresulted in a time- and dose-dependent increase in urinary NOx excretion. Translocation was a prerequisite for inducing a NOx response, since heat-killed L. monocytogenes did not elevate NOx excretion in urine. Fecal counts of listeria also showed dose and time dependency. Moreover, the number of viable L. monocytogenes cells in mesenteric lymph nodes also increased in a dose-dependent manner and correlated with urinary NOx. In conclusion, urinary NOx is a quantitative, noninvasive biomarker of listeria translocation.

Noroviruses Cause Half of Food-Borne Infections in the U.S.

2012 ◽  
Vol 46 (12) ◽  
pp. 1-2
Author(s):  
DOUG BRUNK
Keyword(s):  
Food Borne ◽  
Food Borne Infections ◽  
The U.S

Biofilm Formation and Associated Genes in Listeria Monocytogenes

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Food Processing ◽  
Biofilm Formation ◽  
Milk Samples ◽  
Biofilm Production ◽  
Food Borne ◽  
Serious Infections ◽  
Microtiter Assay

Listeria monocytogenes, an opportunistic food borne pathogen can cause serious infections in immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments.The biofilm transfers contamination to food products and impose risk to public health. In the present study biofilm producing ability of L. monocytogenes isolates were investigated phenotypically and genotypically by microtiter assay and multiplex PCR, respectively. Out of 38 L. monocytogenes isolates 14 were recovered from animal clinical cases, 12 bovine environment and 12 from milk samples. A total of 3 (21.42%) clinical, 2 (16.66%) environment and 3 (25%) milk samples respectively, revealed biofilm production in microtiter assay. Cumulative results showed that 23 (60.52%) out of 38 strains of L. monocytogenes were positive for luxS and flaA gene and 1 (2.63%) was positive only for the flaA gene.

scholarly journals Effect of Gaseous Ozone on Listeria monocytogenes Planktonic Cells and Biofilm: An In Vitro Study

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1484
Author(s):  
Felice Panebianco ◽  
Selene Rubiola ◽  
Francesco Chiesa ◽  
Tiziana Civera ◽  
Pierluigi Aldo Di Ciccio
Keyword(s):  
Listeria Monocytogenes ◽  
In Vitro Study ◽  
Planktonic Cells ◽  
Free Living ◽  
Biofilm Inhibition ◽  
Additional Tool ◽  
Complete Inactivation ◽  
Gaseous Ozone ◽  
Food Borne

Among food-borne pathogens, Listeria monocytogenes continues to pose concerns to food business operators due to its capacity to form biofilm in processing environments. Ozone may be an eco-friendly technology to control microbial contaminations, but data concerning its effect on Listeria monocytogenes biofilm are still limited. In this study, the effect of gaseous ozone at 50 ppm on planktonic cells and biofilm of reference and food-related Listeria monocytogenes strains was evaluated. Ozone caused a reduction in microbial loads of 3.7 ± 0.4 and 3.9 ± 0.4 Log10 CFU/mL after 10 and 30 min, respectively. A complete inactivation of planktonic cells after 6 h of treatment was observed. Biofilm inhibition and eradication treatments (50 ppm, 6 h) resulted in a significant decrease of the biofilm biomass for 59% of the strains tested, whilst a slight dampening of live cell loads in the biofilm state was observed. In conclusion, gaseous ozone is not sufficient to completely counteract Listeria monocytogenes biofilm, but it may be useful as an additional tool to contrast Listeria monocytogenes free-living cells and to improve the existing sanitization procedures in food processing environments.

scholarly journals Bacteriophage Encapsulation in pH-Responsive Core-Shell Capsules as an Animal Feed Additive

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1131
Author(s):  
Kerry Richards ◽  
Danish J. Malik
Keyword(s):  
Animal Feed ◽  
Feed Additive ◽  
Core Shell ◽  
Ph Responsive ◽  
Zoonotic Infections ◽  
The Core ◽  
Extrusion Processing ◽  
Food Borne ◽  
Wet Heat ◽  
Food Borne Infections

Increasing antibiotic resistance in bacteria that cause zoonotic infections is a major problem for farmers rearing animals for food as well as for consumers who eat the contaminated meat resulting in food-borne infections. Bacteriophages incorporated in animal feed may help reduce carriage and infections in animals including chickens and pigs. There are, however, unmet challenges in protecting phages from processing stresses e.g., during animal feed pelleting operations and during transit of phages through the acidic gastric environment. Core-shell capsules were produced using a concentric nozzle and commercially available encapsulation equipment to fabricate capsules with phages formulated in an oil-in-water microemulsion in the core. pH-responsive capsules released the encapsulated phage cargo within 10–30 min triggered by changes in local environmental pH typically found in the lower gastrointestinal (GI) tract of animals. Acid stability of phages exposed to pH values as low as pH 1 was demonstrated. Encapsulated phages were able to withstand exposure to 95 °C wet heat thermal stress for up to 120 s, conditions typically encountered during feed pellet extrusion processing. Free phages were inactivated within 15 s under these conditions. The present study demonstrates that encapsulation of bacteriophages in core-shell pH-responsive capsules with water-in-oil emulsified phages in the core significantly improves phage viability upon exposure to processing and environmental stresses that require consideration during production of animal feed and application in animals for biocontrol. The results from this study should help guide future development of phage formulations suitable for use in animal feed for animal biocontrol applications.

scholarly journals Gbu Glycine Betaine Porter and Carnitine Uptake in Osmotically Stressed Listeria monocytogenes Cells

2002 ◽  
Vol 68 (11) ◽  
pp. 5647-5655 ◽  
Author(s):  
Mary Lou Mendum ◽  
Linda Tombras Smith
Keyword(s):  
Listeria Monocytogenes ◽  
Transport System ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
High Salt ◽  
Uptake System ◽  
Food Borne ◽  
Protein Mutants ◽  
Carnitine Uptake ◽  
Do So

ABSTRACT The food-borne pathogen Listeria monocytogenes grows actively under high-salt conditions by accumulating compatible solutes such as glycine betaine and carnitine from the medium. We report here that the dominant transport system for glycine betaine uptake, the Gbu porter, may act as a secondary uptake system for carnitine, with a Km of 4 mM for carnitine uptake and measurable uptake at carnitine concentrations as low as 10 μM. This porter has a Km for glycine betaine uptake of about 6 μM. The dedicated carnitine porter, OpuC, has a Km for carnitine uptake of 1 to 3 μM and a V max of approximately 15 nmol/min/mg of protein. Mutants lacking either opuC or gbu were used to study the effects of four carnitine analogs on growth and uptake of osmolytes. In strain DP-L1044, which had OpuC and the two glycine betaine porters Gbu and BetL, triethylglycine was most effective in inhibiting growth in the presence of glycine betaine, but trigonelline was best at inhibiting growth in the presence of carnitine. Carnitine uptake through OpuC was inhibited by γ-butyrobetaine. Dimethylglycine inhibited both glycine betaine and carnitine uptake through the Gbu porter. Carnitine uptake through the Gbu porter was inhibited by triethylglycine. Glycine betaine uptake through the BetL porter was strongly inhibited by trigonelline and triethylglycine. These results suggest that it is possible to reduce the growth of L. monocytogenes under osmotically stressful conditions by inhibiting glycine betaine and carnitine uptake but that to do so, multiple uptake systems must be affected.

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 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.

Sign in / Sign up

Export Citation Format

Share Document