Analysis of virulence genes and molecular typing of Listeria monocytogenes isolates from human, food, and livestock from 2008 to 2016 in Iran

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Masoud Naghizadeh Heidarlo ◽  
Lida Lotfollahi ◽  
Saber Yousefi ◽  
Vahid Lohrasbi ◽  
Gholamreza Irajian ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Molecular Typing ◽  
Virulence Genes ◽  
Human Food

scholarly journals Whole genome sequencing for typing and characterisation of Listeria monocytogenes isolated in a rabbit meat processing plant

2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Federica Palma ◽  
Frédérique Pasquali ◽  
Alex Lucchi ◽  
Alessandra De Cesare ◽  
Gerardo Manfreda
Keyword(s):  
Listeria Monocytogenes ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Molecular Typing ◽  
Virulence Genes ◽  
Processing Plant ◽  
Whole Genome ◽  
Meat Processing ◽  
Typing Methods ◽  
Rabbit Meat

Listeria monocytogenes is a food-borne pathogen able to survive and grow in different environments including food processing plants where it can persist for month or years. In the present study the discriminatory power of Whole Genome Sequencing (WGS)-based analysis (cgMLST) was compared to that of molecular typing methods on 34 L. monocytogenes isolates collected over one year in the same rabbit meat processing plant and belonging to three genotypes (ST14, ST121, ST224). Each genotype included isolates indistinguishable by standard molecular typing methods. The virulence potential of all isolates was assessed by Multi Virulence-Locus Sequence Typing (MVLST) and the investigation of a representative database of virulence determinant genes. The whole genome of each isolate was sequenced on a MiSeq platform. The cgMLST, MVLST, and in silico identification of virulence genes were performed using publicly available tools. Draft genomes included a number of contigs ranging from 13 to 28 and N50 ranging from 456298 to 580604. The coverage ranged from 41 to 187X. The cgMLST showed a significantly superior discriminatory power only in comparison to ribotyping, nevertheless it allows the detection of two singletons belonging to ST14 that were not observed by other molecular methods. All ST14 isolates belonged to VT107, which 7-loci concatenated sequence differs for only 4 nucleotides to VT1 (Epidemic clone III). Analysis of virulence genes showed the presence of a fulllength inlA version in all ST14 isolates and of a mutated version including a premature stop codon (PMSC) associated to attenuated virulence in all ST121 isolates.

Low Potential Virulence Associated with Mutations in the inlA and prfA Genes in Listeria monocytogenes Isolated from Raw Retail Poultry Meat

2013 ◽  
Vol 76 (1) ◽  
pp. 129-132 ◽  
Author(s):  
VICTORIA LÓPEZ ◽  
JAIME NAVAS ◽  
JOAQUÍN V. MARTÍNEZ-SUÁREZ
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Virulence Genes ◽  
Pulsed Field Gel Electrophoresis ◽  
Poultry Meat ◽  
Pathogenic Potential ◽  
Molecular Serotyping ◽  
Potential Source ◽  
Raw Foods ◽  
Over Time

Packaged raw foods can represent a potential source of Listeria monocytogenes contamination when opened at home, and listeriosis is associated with the consumption of undercooked raw foods. The aim of this study was to characterize a group of L. monocytogenes strains isolated from 56 packages of raw chicken meat from a single brand in order to determine the diversity of the strains that dominate in a particular food over time, as well as their pathogenic potential. Forty (71%) samples were found to be positive for L. monocytogenes, and three isolates per sample were subjected to PCR molecular serotyping. Subtyping of 45 isolates from different manufacturing dates (n = 40) or different molecular serotype within the same sample (n = 5) identified 11 different L. monocytogenes subtypes as defined by pulsed-field gel electrophoresis and sequencing of virulence genes actA and inlA. Two of the subtypes accounted for 51% of the isolates. About 40% of isolates (three subtypes) were found to potentially present attenuated virulence because of the presence of mutations in the prfA and inlA genes.

scholarly journals Transport and Catabolism of Pentitols by Listeria monocytogenes

2016 ◽  
Vol 26 (6) ◽  
pp. 369-380 ◽  
Author(s):  
Takfarinas Kentache ◽  
Eliane Milohanic ◽  
Thanh Nguyen Cao ◽  
Abdelhamid Mokhtari ◽  
Francine Moussan Aké ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Pentose Phosphate ◽  
Phosphotransferase System ◽  
Virulence Gene Expression ◽  
Transposon Insertion ◽  
Encoding Gene ◽  
High Concentrations ◽  
Transcription Activators

Transposon insertion into <i>Listeria monocytogenes lmo2665</i>, which encodes an EIIC of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS), was found to prevent <smlcap>D</smlcap>-arabitol utilization. We confirm this result with a deletion mutant and show that Lmo2665 is also required for <smlcap>D</smlcap>-xylitol utilization. We therefore called this protein EIIC<sup>Axl</sup>. Both pentitols are probably catabolized via the pentose phosphate pathway (PPP) because <i>lmo2665</i> belongs to an operon, which encodes the three PTS<sup>Axl</sup> components, two sugar-P dehydrogenases, and most PPP enzymes. The two dehydrogenases oxidize the pentitol-phosphates produced during PTS-catalyzed transport to the PPP intermediate xylulose-5-P. <i>L. monocytogenes</i> contains another PTS, which exhibits significant sequence identity to PTS<sup>Axl</sup>. Its genes are also part of an operon encoding PPP enzymes. Deletion of the EIIC-encoding gene <i>(lmo0508)</i> affected neither <smlcap>D</smlcap>-arabitol nor <smlcap>D</smlcap>-xylitol utilization, although <smlcap>D</smlcap>-arabitol induces the expression of this operon. Both operons are controlled by MtlR/LicR-type transcription activators (Lmo2668 and Lmo0501, respectively). Phosphorylation of Lmo0501 by the soluble PTS<sup>Axl</sup> components probably explains why <smlcap>D</smlcap>-arabitol also induces the second pentitol operon. Listerial virulence genes are submitted to strong repression by PTS sugars, such as glucose. However, <smlcap>D</smlcap>-arabitol inhibited virulence gene expression only at high concentrations, probably owing to its less efficient utilization compared to glucose.

Analysis of Additional Virulence Genes and Virulence Gene Regions in Listeria monocytogenes Confirms the Epidemiologic Relevance of Multi-Virulence-Locus Sequence Typing

2008 ◽  
Vol 71 (12) ◽  
pp. 2559-2566 ◽  
Author(s):  
SARA LOMONACO ◽  
YI CHEN ◽  
STEPHEN J. KNABEL
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Listeria Monocytogenes ◽  
Virulence Genes ◽  
Virulence Gene ◽  
The Other ◽  
Evolutionary Divergence ◽  
Gene Sequences ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Molecular Subtyping

Previous molecular subtyping studies have defined four epidemic clones (ECs) of Listeria monocytogenes (ECI, ECII, ECIII, and ECIV). Partial sequences of eight virulence genes were previously shown to be identical within individual ECs of L. monocytogenes. The present study was conducted to determine if the sequences of other virulence genes and virulence gene regions are also conserved within these ECs. Six additional virulence genes—bsh, hly, inlJ, lplA1, pgdA, and srtA—and three additional virulence gene regions of actA, inlA, and inlB were selected based on their role in L. monocytogenes virulence, and intragenic regions of each gene were sequenced. Sequencing was performed on a diverse set of 44 to 48 L. monocytogenes strains. Results demonstrated that the sequenced regions of the nine virulence genes were identical within each of the ECs, and 257 new single nucleotide polymorphism (SNPs) were identified. ECIII (lineage II) was easily distinguishable from the other ECs, as 238 SNPs were observed in ECIII due to its significant evolutionary divergence from lineage I. With regard to the other ECs, there were 5 SNPs that represented an informative set, since these SNPs were able to differentiate specific ECs from all other unrelated strains used in this study. This study confirms our previous finding that virulence gene sequences are highly conserved within individual ECs and contain stable SNPs that can be used to very accurately differentiate ECs of L. monocytogenes from each other and from other diverse strains.

Differences in virulence and in expression of PrfA and PrfA-regulated virulence genes of Listeria monocytogenes strains belonging to serogroup 4.

1996 ◽  
Vol 64 (10) ◽  
pp. 4008-4019 ◽  
Author(s):  
Z Sokolovic ◽  
S Schüller ◽  
J Bohne ◽  
A Baur ◽  
U Rdest ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Virulence Genes

Listeria monocytogenes From Farm to Fork in a Brazilian Pork Production Chain

2020 ◽  
Vol 83 (3) ◽  
pp. 485-490 ◽  
Author(s):  
DANILO A. L. SILVA ◽  
CLARISSE V. BOTELHO ◽  
BRUNA T. F. MARTINS ◽  
RAFAELA M. TAVARES ◽  
ANDERSON C. CAMARGO ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Virulence Genes ◽  
Pulsed Field Gel Electrophoresis ◽  
Control Measures ◽  
Production Chain ◽  
Pork Production ◽  
Pulsed Field ◽  
Genetic Profiles ◽  
Different Sources

ABSTRACT Listeria monocytogenes contamination was assessed in different steps of a pork production chain. Ten lots of pigs were sampled at termination barns, at slaughter (after bleeding, after buckling, after evisceration, and after final washing), at processing (knives, deboning tables, and employees' hands), and of end products (ribs, shoulder, ham, and sausage). All samples (n = 670) were subjected to L. monocytogenes detection, and the obtained isolates (n = 18, identified as Listeria spp.) were characterized by their biochemical characteristics, serogroups, virulence genes, pulsed-field gel electrophoresis profiles, antibiotic resistances (ampicillin, penicillin, gentamicin, and sulfamethoxazole-trimethoprim), and adhesion abilities. The results revealed the low occurrence of Listeria spp. in the evaluated pork production chain. However, four tested sausage samples (40%) were positive for Listeria spp., with L. monocytogenes identified in two (20%) of these samples. Ten isolates were identified as L. monocytogenes (eight from serogroup 1/2a or 3a and two from serogroup 4b, 4d, or 4e): all isolates were also positive for the virulence-related genes hlyA, iap, plcA, actA, inlA, inlB, inlC, and inlJ and susceptible to the tested antibiotics. One sausage sample was contaminated by both serogroups 1/2a or 3a and 4b, 4d, or 4e. Isolates from serogroup 1/2a or 3a obtained during visits 5 and 6 presented distinct genetic profiles by pulsed-field gel electrophoresis, indicating that contamination may come from different sources. The adhesion potential exhibited by Listeria spp. isolates (n = 18) ranged from weak (serogroup 4b, 4d, or 4e) to moderate (L. innocua and L. monocytogenes serogroup 1/2a or 3a). Despite the low occurrence of L. monocytogenes, pathogenic serogroups were detected in sausages, demanding control measures by the industry. HIGHLIGHTS

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