scholarly journals Population Genetic Structure of Listeria monocytogenes Strains as Determined by Pulsed-Field Gel Electrophoresis and Multilocus Sequence Typing

2016 ◽  
Vol 82 (18) ◽  
pp. 5720-5728 ◽  
Author(s):  
Clémentine Henri ◽  
Benjamin Félix ◽  
Laurent Guillier ◽  
Pimlapas Leekitcharoenphon ◽  
Damien Michelon ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Food Safety ◽  
Genetic Structure ◽  
Gel Electrophoresis ◽  
Dairy Products ◽  
Population Genetic ◽  
Meat Products ◽  
Pulsed Field Gel Electrophoresis ◽  
Content Type ◽  
Food Matrices

ABSTRACTListeria monocytogenesis a ubiquitous bacterium that may cause the foodborne illness listeriosis. Only a small amount of data about the population genetic structure of strains isolated from food is available. This study aimed to provide an accurate view of theL. monocytogenesfood strain population in France. From 1999 to 2014, 1,894L. monocytogenesstrains were isolated from food at the French National Reference Laboratory forL. monocytogenesand classified according to the five risk food matrices defined by the European Food Safety Authority (EFSA). A total of 396 strains were selected on the basis of different pulsed-field gel electrophoresis (PFGE) clusters, serotypes, and strain origins and typed by multilocus sequence typing (MLST), and the MLST results were supplemented with MLST data available from Institut Pasteur, representing human and additional food strains from France. The distribution of sequence types (STs) was compared between food and clinical strains on a panel of 675 strains. High congruence between PFGE and MLST was found. Out of 73 PFGE clusters, the two most prevalent corresponded to ST9 and ST121. Using original statistical analysis, we demonstrated that (i) there was not a clear association between ST9 and ST121 and the food matrices, (ii) serotype IIc, ST8, and ST4 were associated with meat products, and (iii) ST13 was associated with dairy products. Of the two major STs, ST121 was the ST that included the fewest clinical strains, which might indicate lower virulence. This observation may be directly relevant for refining risk analysis models for the better management of food safety.IMPORTANCEThis study showed a very useful backward compatibility between PFGE and MLST for surveillance. The results enabled better understanding of the population structure ofL. monocytogenesstrains isolated from food and management of the health risks associated withL. monocytogenesfood strains. Moreover, this work provided an accurate view ofL. monocytogenesstrain populations associated with specific food matrices. We clearly showed that some STs were associated with food matrices, such as meat, meat products, and dairy products. We opened the way to source attribution modeling in order to quantify the relative importance of the main food matrices.

scholarly journals Whole-Genome Sequences of Two Listeria monocytogenes Serovar 1/2a Strains Responsible for a Severe Listeriosis Outbreak in Central Italy

2018 ◽  
Vol 6 (24) ◽  
Author(s):  
Massimiliano Orsini ◽  
Alessandra Cornacchia ◽  
Claudio Patavino ◽  
Marina Torresi ◽  
Patrizia Centorame ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Central Italy ◽  
Pulsed Field Gel Electrophoresis ◽  
Single Band ◽  
Whole Genome ◽  
Genome Sequences ◽  
Content Type ◽  
Pulsed Field ◽  
Pfge Profiles

ABSTRACT We report the whole-genome sequences of two Listeria monocytogenes strains responsible for a severe invasive listeriosis outbreak in central Italy that occurred in 2015 and 2016. These two strains differ by a single band in their pulsed-field gel electrophoresis (PFGE) profiles.

Analysis of Listeria monocytogenes Strain Distribution in a Pork Slaughter and Cutting Plant in the Province of Quebec

2014 ◽  
Vol 77 (12) ◽  
pp. 2121-2128 ◽  
Author(s):  
GUILLAUME LARIVIÉRE-GAUTHIER ◽  
ANN LETELLIER ◽  
ANNAËLLE KÉROUANTON ◽  
SADJIA BEKAL ◽  
SYLVAIN QUESSY ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Food Production ◽  
Control Strategies ◽  
Meat Products ◽  
Pulsed Field Gel Electrophoresis ◽  
Public Health Perspective ◽  
Pulsed Field ◽  
Plant Environment ◽  
Production Stages

Following the 2008 Canadian listeriosis outbreak associated with ready-to-eat (RTE) meat products, regulations on the presence of Listeria monocytogenes in RTE food production facilities were modified by Health Canada, confirming the need to control this pathogen, not only in the final product but also in the plant environment. Information on the occurrence of this microorganism during the early steps of production, such as the slaughtering process and in the cutting area, is scarce in Canada. In this study, we sampled different production steps in a slaughtering and cutting plant in the province of Quebec over a 2-year period. The lairage pens, representative areas of the slaughter line, and cutting zones were targeted after their respective cleaning procedures. A total of 874 samples were analyzed for the presence of L. monocytogenes. Characterization was done by first genoserogrouping the isolates using multiplex PCR and then using a pulsed-field gel electrophoresis approach. L. monocytogenes was detected throughout all production stages. The 108 positive samples found were analyzed further, and we established that there were 4 different serogroups, with serogroup IIb being the most prevalent. The results of pulsed-field gel electrophoresis analysis showed a significant decrease in the diversity of strains from the first areas of the plant to the cutting room (10 pulsotypes in 13 positive samples in lairage and 9 in 86 positive samples in cutting) and also showed the overrepresentation of a single predominant strain in the cutting room environment (type 1, representing 96.1% of the isolates). Biofilm formation analysis of the strains cannot exclusively explain the transitions we observed. A strong genotypic similarity between strains isolated in the early production areas and some strains in the cutting room was shown. These results support the need for better surveillance of L. monocytogenes prior to RTE food production in order to design control strategies that are better adapted from a public health perspective.

scholarly journals Characterization of epidemic clones of Listeria monocytogenes serotype 4b isolated from humans and meat products in Brazil

2015 ◽  
Vol 9 (09) ◽  
pp. 962-969 ◽  
Author(s):  
André Victor Barbosa ◽  
Aloysio de Mello Figueiredo Cerqueira ◽  
Leonardo Alves Rusak ◽  
Cristhiane Moura Falavina Dos Reis ◽  
Nilma Cintra Leal ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Virulence Genes ◽  
Foodborne Pathogen ◽  
Meat Products ◽  
Human Case ◽  
Pulsed Field Gel Electrophoresis ◽  
Clinical Samples ◽  
Pulsed Field ◽  
Serotype 4B

Introduction: Listeria monocytogenes is an important foodborne pathogen and the 4b serotype is responsible for many cases of human listeriosis reported in Brazil. Several listeriosis outbreaks worldwide have involved a small number of well-defined clonal groups, designated as epidemic clones (ECs). Methodology: We studied 71 strains of serotype 4b, including 25 isolates from human cases of listeriosis and 46 from meat-based foods, collected in Brazil between 1977 and 2010. The presence of ECs (I and II) markers and virulence genes (inlA, inlB, ilnC, inlJ and actA) were evaluated by PCR assay. The genetic relationship of ECs-positive strains was assessed by pulsed field gel electrophoresis. Results: ECI and ECII markers were found both in human and food strains, with 19.7% positive for the ECI marker and 40.8% for ECII. Most strains (97.2%) were positive for the virulence genes that were studied. Nevertheless, the actA gene amplicons showed two distinct sizes, with all ECI positive strains exhibiting a 105bp deletion. Pulsed field gel electrophoresis (PFGE) analysis allowed the recognition of highly related strains, particularly from two outbreaks of neonatal listeriosis in São Paulo State occurred in 1992 and 1997, both ECII-positive; and two ECI strains from a human case (1982) and from bovine meat (2009). Conclusions: The presence of ECs among clinical samples and beef isolates of serotype 4b from some regions of Brazil highlights the need for rigorous control of production procedures. Furthermore, the association of ECII with two nosocomial outbreaks suggests its ability to spread in these settings.

scholarly journals Population Genetic Structure of 4,12:a:− Salmonella enterica Strains from Harbor Porpoises

2012 ◽  
Vol 78 (24) ◽  
pp. 8829-8833 ◽  
Author(s):  
Jana K. Haase ◽  
Derek J. Brown ◽  
François-Xavier Weill ◽  
Henry Mather ◽  
Geoffrey Foster ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Population Genetic ◽  
Pulsed Field Gel Electrophoresis ◽  
Genetic Cluster ◽  
Content Type ◽  
Pfge Typing ◽  
Harbor Porpoises ◽  
Sequence Types ◽  
Specific Sequences

ABSTRACTAccording to pulsed-field gel electrophoresis (PFGE) typing, 4,12:a:−Salmonella entericaisolates from harbor porpoises are highly diverse. However, porpoise isolates belong to only two multilocus sequence types within the eBurst group 18 (eBG18) genetic cluster, which also includesS. entericaserovars Bispebjerg and Abortusequi. Isolates of other, serologically similar serovars belong to unrelated eBGs. These assignments to eBGs were supported by eBG-specific sequences of the flagellar genefliC.

scholarly journals Caracterização molecular de Listeria monocytogenes oriundas de cortes cárneos bovinos e de abatedouros frigoríficos de bovinos localizados no Distrito Federal, Brasil

2016 ◽  
Vol 36 (10) ◽  
pp. 957-964 ◽  
Author(s):  
Joana M. Palma ◽  
◽  
Rodrigo C. Lisboa ◽  
Dália P. Rodrigues ◽  
André F.M. Santos ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field ◽  
Distrito Federal

RESUMO: Este trabalho teve como objetivo realizar a detecção de cepas de Listeria monocytogenes de cortes cárneos bovinos bem como no ambiente de abatedouros frigoríficos localizados no Distrito Federal, promover a sorotipificação pela reação em cadeia da polimerase (PCR), realizar antibiograma e submeter às cepas à eletroforese de campo pulsado (Pulsed-field gel electrophoresis - PFGE). Foram analisados um total de 125 cortes cárneos bovinos, 45 amostras de swabs de carcaças e 43 amostras de swabs em que foram detectados 13 cepas de Listeria monocytogenes, sendo 11 em cortes cárneos bovinos e 2 swabs de ambiente em um abatedouro frigorifico. Não foram isoladas cepas de swabs de carcaça. Dentre as 13 cepas de Listeria monocytogenes foram encontradas seis cepas do sorotipo 4b, cinco do sorotipo 1/2c e duas cepas do sorotipo 1/2a. Dentre as 11 cepas de L. monocytogenes encontradas em cortes cárneos bovino, uma (9,1%) cepa apresentou resistência a eritromicina, outra (9,1%) cepa a gentamicina e outra a ciprofloxacina (9,1%) e todas as cepas (100%) apresentaram resistência ao Ác. Nalidíxico. Das duas (2) cepas oriundas de ralos de abatedouro frigorífico, todas (100%) apresentaram resistência ao Ác. Nalidíxico e a sulfonamidas. A análise por eletroforese de campo pulsante (PFGE) demonstrou 13 diferentes pulsotipos, em que foram agrupados em 3 diferentes grupos clonais, que coincidentemente se correlacionavam com os 3 diferentes sorotipos encontrados sugerindo uma ampla disseminação desses perfis no Distrito Federal.

Isolation and Pulsed-Field Gel Electrophoresis Typing of Listeria monocytogenes from Modified Atmosphere Packaged Fresh-Cut Vegetables Collected in Ireland

2006 ◽  
Vol 69 (10) ◽  
pp. 2524-2528 ◽  
Author(s):  
GILLIAN A. FRANCIS ◽  
DAVID O'BEIRNE
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Fruits And Vegetables ◽  
Pulsed Field Gel Electrophoresis ◽  
Leafy Vegetables ◽  
Modified Atmosphere ◽  
Pulsed Field ◽  
Fruit Samples ◽  
Fresh Cut ◽  
Pfge Profiles

The incidence of Listeria monocytogenes in modified atmosphere packaged fresh-cut fruits and vegetables from chill cabinets of a supermarket in Ireland was investigated over a 2-year period. Overall, 9.58% of fresh-cut produce was contaminated with Listeria spp. Various species of Listeria were isolated from samples, including L. monocytogenes, L. seeligeri, L. innocua, L. welshimeri, and L. ivanovii. No fruit samples contained detectable L. monocytogenes. Overall, a total of 21 L. monocytogenes isolates (2.9% of samples) were recovered from a range of products, including dry coleslaw mix (80% shredded cabbage and 20% shredded carrot), bean sprouts, and leafy vegetables such iceberg, romaine, and radicchio lettuce and mixed salad leaves (curly endive, escarole, and radicchio leaves). Dry coleslaw mix appeared to have the highest incidence of Listeria contamination (20%) compared with other products. Listeria contamination was more frequent (P < 0.05) during the summer and autumn months than during the winter and spring months. The 21 L. monocytogenes isolates were subsequently subtyped by genomic macrorestriction techniques using ApaI with pulsed-field gel electrophoresis (PFGE). PFGE of digested DNA produced bands of 79 to 518 kb. Four PFGE profiles were identified, and approximately 50% of the isolates were associated with profile 1. This study indicates that fresh-cut vegetables packaged under a modified atmosphere can support growth of numerous species of Listeria, including L. monocytogenes.

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 Sources of Listeria monocytogenes Contamination in a Cold-Smoked Rainbow Trout Processing Plant Detected by Pulsed-Field Gel Electrophoresis Typing

1999 ◽  
Vol 65 (1) ◽  
pp. 150-155 ◽  
Author(s):  
Tiina Autio ◽  
Sebastian Hielm ◽  
Maria Miettinen ◽  
Anna-Maija Sjöberg ◽  
Kaarina Aarnisalo ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Hot Water ◽  
Processing Plant ◽  
Pulsed Field ◽  
Eradication Program ◽  
Fish Samples ◽  
Raw Fish

ABSTRACT Sites of Listeria monocytogenes contamination in a cold-smoked rainbow trout (Oncorhynchus mykiss) processing plant were detected by sampling the production line, environment, and fish at different production stages. Two lots were monitored. The frequency of raw fish samples containing L. monocytogenes was low. During processing, the frequency of fish contaminated with L. monocytogenes clearly rose after brining, and the most contaminated sites of the processing plant were the brining and postbrining areas. A total of 303 isolates from the raw fish, product, and the environment were characterized by pulsed-field gel electrophoresis (PFGE). PFGE yielded nine pulsotypes, which formed four clusters. The predominating L. monocytogenespulsotypes of the final product were associated with brining and slicing, whereas contaminants of raw fish were not detected in the final product. Air-mediated contamination in the plant could not be proved. In accordance with these results, an L. monocytogenes eradication program was planned. The use of hot steam, hot air, and hot water seemed to be useful in eliminatingL. monocytogenes. None of the control samples taken in the 5 months after the eradication program was implemented containedL. monocytogenes.

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