Listeria monocytogenes clones in Italian food products: virulence and environmental adaptation

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Torresi ◽  
A Rinaldi ◽  
G Centorotola ◽  
M Di Domenico ◽  
C Cammà ◽  
...  
Keyword(s):  
European Union ◽  
Listeria Monocytogenes ◽  
Stress Resistance ◽  
In Silico ◽  
Meat Products ◽  
Production Environment ◽  
Genome Profile ◽  
European Union Level ◽  
Pan Genome ◽  
Fish Samples

Abstract Background Food is the main source of Listeria monocytogenes (Lm) infection. Lm is a highly heterogeneous species composed of hypervirulent and hypovirulent clones. Understanding the distribution of Lm clonal complexes (CCs) in different food categories has strong implications for risk assessment. The aim of this work was to analyse collection of Lm strains of National Reference Laboratory (NRL Lm) in order to assess link between genetic profile and matrices and the level of pathogenicity of circulating strains based on CCs. Methods NRL Lm database actually consists of 906 sequenced strains isolated in 10 years from 5 food compartments (meat, fish, dairy, vegetables and composite dishes). Epidata were analysed to remove redundant strains based on the same epidemiological description. After that, WGS data from 465 Lm strains were investigated. In silico MLST was defined and Roary 3.12.0 was used to obtain a pan-genome profile. Genes were later uploaded to Pasteur Institute platform for characterization. Results In silico MLST identified 36 CCs and 6 singleton. CC9 (23.0%), CC8 (15.3%) and CC121 (13.3%) were the prevalent CCs. In particular, CC9 was present in 35.2% of meat samples and CC8 in 25.8% of fish samples. Pan genome profile revealed high prevalence (>98%) of genes related to biofilm formation and resistance to environmental stress in CC9 strains and genes involved in tolerance to quaternary ammonium compounds in CC121 strains. Conclusions Results, in particular for meat products, confirmed in Italy, the prevalence of hypovirulent Lm strains previously observed at European Union level. The high presence of stress resistance and disinfectant tolerance genes in these strains could make them able to persist in food-production environment and should be taken into account evaluating the health hazards. In fish product is also relevant the prevalence of CC8 strains which are potentially highly pathogenic and have been responsible of recent European multi country outbreak. Key messages Pangenome of Listeria monocytogenes isolated from Italian food revealed high presence of disinfectant tolerance and stress resistance genes in meat products and virulence genes in fish products. Listeria monocytogenes CC9 and CC121 prevalence in Italian meat product confirms occurrence of hypovirulent strains detected at European Union level.

scholarly journals INFLUENCES OF THE PURCHASING POWER CHANGE ON THE EVOLUTION OF THE AGROALIMETARY MARKETS ON EUROPEAN UNION LEVEL

2013 ◽  
Author(s):  
Laura Catalina Timiras
Keyword(s):  
European Union ◽  
Edible Oils ◽  
Meat Products ◽  
Point Of View ◽  
Purchasing Power ◽  
The European Union ◽  
Tobacco Products ◽  
European Union Level ◽  
Power Change ◽  
Per Capita

This paper aims to identify the manifested connection between the dynamics of the population purchasing power and the dynamic of agroalimentary markets in general as well as by product types on European Union level. Based on the last data supplied by Eurostat 2013, using the specific methods for studying the correlations, we have detected that increases and decreases of the purchasing power generated similar changes on agroalimentary markets level from the point of view of achieved sales in most of the poorer countries of the European Union, but not in those states which got beyond the average gross domestic product per capita of the European Union. This relationship has been noticed only on the agroalimentary markets as a whole (respectively on the amounts spent by the population for purchasing agroalimentary goods, beverages and tobacco), but not on the level of markets of various types of product (“meat and meat products”, “fruit and vegetables”, “dairy produce, eggs and edible oils and fats”, “beverages”, “sugar and chocolate and sugar confectionery”, “tobacco products”).

scholarly journals Detection of Listeria monocytogenes in Several Types of Frozen Meat in Baghdad city

2021 ◽  
pp. 742-750
Author(s):  
Safana A. S. Yassin ◽  
Ban N. Nadhom ◽  
Nagham M. Al-Gburi
Keyword(s):  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Meat Products ◽  
Red Meat ◽  
The Other ◽  
Contamination Rate ◽  
Rt Pcr ◽  
Biochemical Tests ◽  
Isolation And Identification ◽  
Fish Samples

Detection of pathogenic bacteria, such as Listeria  monocytogenes, in food is crucial for safeguarding public health in Iraq.  Forty five samples of frozen meat (15 samples of each of minced red meat, chicken, and fish) were collected from different markets in Baghdad city. Molecular (RT-PCR) and culturing (conventional microbiological examination) methods were used to determine the level of contamination of L. monocytogenes in these types of meat. For the culturing method, TSYEB broth was used as an enrichment medium, whereas BALCAM medium (HiMedia) with the listeria selective supplement FD061 was used as a selective medium, for the isolation and identification of this bacterium. The isolates were confirmed microscopically and biochemically. The results of the culturing method showed that the total number of the isolates of L. monocytogenes was 14/45 (31.1%). The incidence of this bacterium was high in fish (11/15, 73.3%), while it was low in the other two types of meat.  2/15 (13.3%) in red meat and 1/15 (6.7 %) in chicken. Molecular detection of each sample of the bacteria was performed using RT-PCR technique after preparing the Genomic DNA extraction of these samples according to the protocol provided by ReliaPrep™ Blood gDNA Miniprep System kit (Promega, USA). The PCR primers and the hybridization probe ((Macrogen, Korea) were used to target the inlA gene sequence (specific for L. monocytogenes). The results of the RT-PCR assay showed that 10/45 (22.2%) of the samples were positive for L. monocytogenes, which was detected only in fish samples ((10/15, 66.7%), while not found in minced red meat and chicken. However, our results showed differences when compared to other previous works because there were many studies found that the highest contamination rate was in red meat products. We conclude that the PCR kit used for the detection of L monocytogenes appears to give accurate results in the diagnoses of this bacterium in meat products and in comparison with the other routine diagnosis methods in the laboratory, which included culturing and doing biochemical tests which last for approximately 7 days, the RT-PCR technique was able to confirm the findings within 48 hours.

scholarly journals Fatty Acids Regulate Stress Resistance and Virulence Factor Production for Listeria monocytogenes

2012 ◽  
Vol 194 (19) ◽  
pp. 5274-5284 ◽  
Author(s):  
Y. Sun ◽  
B. J. Wilkinson ◽  
T. J. Standiford ◽  
H. T. Akinbi ◽  
M. X. D. O'Riordan
Keyword(s):  
Fatty Acids ◽  
Listeria Monocytogenes ◽  
Virulence Factor ◽  
Stress Resistance ◽  
Factor Production ◽  
Virulence Factor Production

Modeling the Growth Boundary of Listeria monocytogenes in Ready-to-Eat Cooked Meat Products as a Function of the Product Salt, Moisture, Potassium Lactate, and Sodium Diacetate Concentrations

2004 ◽  
Vol 67 (10) ◽  
pp. 2195-2204 ◽  
Author(s):  
J. D. LEGAN ◽  
D. L. SEMAN ◽  
A. L. MILKOWSKI ◽  
J. A. HIRSCHEY ◽  
M. H. VANDEVEN
Keyword(s):  
Listeria Monocytogenes ◽  
Meat Products ◽  
Growth Conditions ◽  
Continuous Variables ◽  
Surface Design ◽  
Potassium Lactate ◽  
Contour Plots ◽  
Sodium Diacetate ◽  
Factor Interactions ◽  
Composite Response

A central composite response surface design was used to determine the time to growth of Listeria monocytogenes as a function of four continuous variables: added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (60% [wt/wt]; 0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) in ready-to-eat cured meat products. The design was repeated for ready-to-eat uncured meat products giving a fifth categorical variable for cure status. Products were stored at 4°C. The results were modeled using a generalized regression approach. All five main effects, six two-factor interactions, and two quadratic terms were statistically significant. The model was used to show the boundary between growth and no-growth conditions at 4°C using contour plots of time to growth. It was validated using independent challenge studies of cured and uncured products. Generally, the model predicted well, particularly for cured products, where it will be useful for establishing conditions that prevent the growth of L. monocytogenes. For uncured products, there was good agreement overall between predicted and observed times to growth, but the model is less thoroughly validated than for cured products. The model should initially only be used for screening of formulations likely to prevent growth of Listeria monocytogenes in uncured products, with recommendations subject to confirmation by challenge studies.

scholarly journals Occurrence of Listeria monocytogenes in Ready-to-Eat Meat Products and Meat Processing Plants in Spain

Foods ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 271-282 ◽  
Author(s):  
Diego Gómez ◽  
Laura Iguácel ◽  
Mª Rota ◽  
Juan Carramiñana ◽  
Agustín Ariño ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Meat Products ◽  
Meat Processing ◽  
Processing Plants

scholarly journals A comparative study of clinical and food isolates ofListeria monocytogenesand related species

1990 ◽  
Vol 105 (2) ◽  
pp. 245-254 ◽  
Author(s):  
E. A. Szabo ◽  
P. M. Desmarchelier
Keyword(s):  
Listeria Monocytogenes ◽  
Comparative Study ◽  
Restriction Endonuclease ◽  
Related Species ◽  
Biochemical Analysis ◽  
Dna Analysis ◽  
Meat Products ◽  
Restriction Patterns

SUMMARYNinety-six isolates of presumptive or confirmedListeria monocytogeneswere obtained from local clinical (30 isolates) or food laboratories (66 isolates). Minimal biochemical analysis identified only 80% of these isolates asL. monocytogenesthe remaining includedL. seeligeri, 1%, or the non-haemolyticL. innocua, 19%. The 27 clinical and 50 food isolates, mainly from meat products, frozen confectionaries, and cheeses, confirmed asL. monocytogeneswere compared biochemically and serologically. Twenty-one isolates, including some strains ofL. innocuaandL. seeligeri, were examined for pathogenicity in immunocompromized mice and 44 typed using bacterial restriction endonuclease DNA analysis (BRENDA). Only isolates ofL. monocytogeneswere found to be pathogenic. Biovar-typing of the isolates was unreliable and provided poor discrimination. Serogroups 1/2 and 4 predominated among clinical and food isolates and BRENDA provided better discrimination among isolates. Ten stable and reproducible restriction patterns were observed among theListeriasp. isolates studied. Overall, a combination of techniques gave the best discrimination and indicated their potential for use as epidemiological tools.

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