Distribution of Epidemic Clonal Genetic Markers among Listeria monocytogenes 4b Isolates

2007 ◽  
Vol 70 (3) ◽  
pp. 574-581 ◽  
Author(s):  
GIOVANNA FRANCIOSA ◽  
CONCETTA SCALFARO ◽  
ANTONELLA MAUGLIANI ◽  
FRANCESCA FLORIDI ◽  
ANTONIETTA GATTUSO ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Genetic Markers ◽  
Pulsed Field Gel Electrophoresis ◽  
Genomic Diversity ◽  
Clinical Isolates ◽  
Specific Marker ◽  
Environmental Isolates ◽  
Environmental Persistence ◽  
Pathogenic Potential ◽  
Serotype 4B

Recent genome sequencing of isolates of Listeria monocytogenes serotype 4b implicated in some major outbreaks of foodborne listeriosis has revealed unique genetic markers in these isolates. The isolates were grouped into two distinct epidemic clones, ECI and ECII. In the present study, selected ECI- and ECII-specific genetic markers were detected in 16 and 15 of 89 L. monocytogenes 4b isolates, respectively. The ECI markers were found in 6 of 34 clinical isolates, 9 of 50 food isolates, and 1 of 5 environmental isolates, and the ECII markers were detected in 7 of 34 clinical isolates, 7 of 50 food isolates, and 1 of 5 environmental isolates. Hence, of the isolates with the epidemic clonal genetic markers, 38% (13 of 34) were of clinical origin, 32% (16 of 50) were of food origin, and 40% (2 of 5) were of environmental origin. The predominance of the epidemic clonal markers among the clinical and environmental isolates supports the hypothesis that these markers are correlated with the pathogenic potential of strains and with their environmental persistence. Several isolates had only one epidemic clonal marker, either the ECI-specific marker 133 or the ECII-specific marker 4bSF18. Pulsed-field gel electrophoresis analysis revealed higher genomic diversity among the strains with ECII-like characteristics than among those strains carrying the ECI-specific genetic markers.

scholarly journals Relatedness of Listeria monocytogenes Isolates Recovered from Selected Ready-To-Eat Foods and Listeriosis Patients in the United States

2005 ◽  
Vol 71 (12) ◽  
pp. 8115-8122 ◽  
Author(s):  
Stefanie Evans Gilbreth ◽  
Jeff E. Call ◽  
F. Morgan Wallace ◽  
Virginia N. Scott ◽  
Yuhuan Chen ◽  
...  
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Food Products ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
Clinical Isolates ◽  
Pulsed Field ◽  
Serotype 1 ◽  
Serotype 4B

ABSTRACT Pulsed-field gel electrophoresis and serotyping were performed for 544 isolates of Listeria monocytogenes, including 502 isolates recovered from contaminated samples from 31,705 retail ready-to-eat (RTE) food products and 42 isolates recovered from human cases of listeriosis. The isolates were from Maryland (294 isolates) and California (250 isolates) and were collected in 2000 and 2001. The isolates were placed into 16 AscI pulsogroups (level of relatedness within each group, ≥66%), 139 AscI pulsotypes (levels of relatedness, ≥25% to 100%), and eight serotypes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 4b, 4c, and 4d). The most frequently found pulsotypes belonged to either pulsogroup A (150 food isolates plus 4 clinical isolates) or pulsogroup B (104 food isolates plus 5 clinical isolates). The majority of the 502 food isolates were either serotype 1/2a (298 isolates) or serotype 1/2b (133 isolates), whereas the majority of the 42 clinical isolates were either serotype 1/2a (19 isolates) or serotype 4b (15 isolates). Additionally, 13 clinical isolates displayed pulsotypes also found in food isolates, whereas the remaining 29 clinical isolates displayed 24 unique pulsotypes. These data indicate that most (86%) of the L. monocytogenes subtypes found in the RTE foods sampled belonged to only two serotypes and that 90% of the isolates displayed 73 pulsotypes, with 107 isolates displaying pulsotype 1. These data should help define the distribution and relatedness of isolates found in RTE foods in comparison with isolates that cause listeriosis.

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 Recurrent and Sporadic Listeria monocytogenes Contamination in Alheiras Represents Considerable Diversity, Including Virulence-Attenuated Isolates

2007 ◽  
Vol 73 (12) ◽  
pp. 3887-3895 ◽  
Author(s):  
M. T. S. Fel�cio ◽  
T. Hogg ◽  
P. Gibbs ◽  
P. Teixeira ◽  
M. Wiedmann
Keyword(s):  
Listeria Monocytogenes ◽  
Control Strategies ◽  
Tetracycline Resistance ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
Pathogenic Potential ◽  
Molecular Serotyping ◽  
Production And Distribution ◽  
Invasion Assays

ABSTRACT Microbiological characterization of alheiras, traditional smoked meat sausages produced in northern Portugal, had previously shown that more than 60% of the lots analyzed were contaminated with Listeria monocytogenes at levels higher than 100 CFU/g. In order to better understand L. monocytogenes contamination patterns in alheiras, we characterized 128 L. monocytogenes isolates from alheiras using a variety of subtyping techniques (i.e., molecular serotyping; arsenic, cadmium, and tetracycline resistance typing; and pulsed-field gel electrophoresis [PFGE]). Subtyping of isolates from products collected on two separate dates provided evidence for the persistence of specific L. monocytogenes PFGE types in the production and distribution chains of alheiras from four different processors. A subset of 21 isolates was further characterized using ribotyping and Caco-2 cell invasion assays to evaluate the pathogenic potential of L. monocytogenes present in alheiras. Caco-2 invasion assays revealed seven isolates with invasion efficiencies that were less than 20% of that of the control strain 10403S. All seven isolates had premature stop codons in inlA that represented three distinct mutations, which had previously been observed in isolates from the United States or France. Our findings indicate the need for a comprehensive approach to control L. monocytogenes in alheiras, including strategies to reduce persistence. The presence of considerable diversity in invasion phenotypes among L. monocytogenes strains present in alheiras, including the presence of subtypes likely to be virulence attenuated, may provide an opportunity to initially focus control strategies on the subtypes most likely to cause human disease.

Traceback Identification of an Ingredient (Pork Dewlap) as the Possible Source of Listeria monocytogenes Serotype 4b Contamination in Raw Chicken Products

2007 ◽  
Vol 70 (6) ◽  
pp. 1513-1517 ◽  
Author(s):  
VICTORIA LÓPEZ ◽  
SAGRARIO ORTIZ ◽  
ALFREDO CORUJO ◽  
PILAR LÓPEZ ◽  
JAIME NAVAS ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Restriction Analysis ◽  
Virulence Gene ◽  
Pulsed Field Gel Electrophoresis ◽  
Processing Plant ◽  
Poultry Processing ◽  
Serotype 4B ◽  
Fresh Products ◽  
Allelic Analysis

In surveys conducted on finished product samples from a single poultry processing plant in Spain, Listeria monocytogenes was found in 14 different uncooked products. To track contamination patterns, 77 L. monocytogenes isolates were characterized by PCR-based serotyping, pulsed-field gel electrophoresis (PFGE) restriction analysis, and PCR-based allelic analysis of the virulence gene actA. Serotyping revealed that 12 isolates (15.6%) were of the L. monocytogenes serotype 4b complex (serotype 4b or the closely related serotypes 4d and 4e). A combination of endonucleases AscI and ApaI PFGE patterns yielded 15 different pulsotypes among all 77 tested isolates. All the serotype 4b isolates belonged to one pulsotype. Sequencing of the actA gene confirmed that all serotype 4b isolates corresponded to the same allelic subtype. The subtype was recovered from five product types, but its presence was not correlated with the production line or the date of isolation, suggesting a possible association of this strain with a common ingredient. This traceback investigation established that pork dewlap, an ingredient common to all the products contaminated with this strain, was the most probable source of L. monocytogenes 4b. The same 4b strain was isolated from four samples of pork dewlap from one specific supplier. After replacement of this contaminated ingredient in the fresh products, this strain of L. monocytogenes serotype 4b was not detected. This study confirms the effectiveness of molecular subtyping to control contamination by specific strains of L. monocytogenes and the importance of testing the different ingredients added to the food products.

scholarly journals Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 742-751 ◽  
Author(s):  
Fadwa Alshareef ◽  
Geoffrey D. Robson
Keyword(s):  
Aspergillus Fumigatus ◽  
Galleria Mellonella ◽  
Rapd Analysis ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Environmental Isolates ◽  
Pathogenic Potential ◽  
Patient Infection ◽  
Selection Of ◽  
Virulence Variation

Environmental populations of the opportunistic pathogen Aspergillus fumigatus have been shown to be genotypically diverse and to contain a range of isolates with varying pathogenic potential. In this study, we combined two RAPD primers to investigate the genetic diversity of environmental isolates from Manchester collected monthly over 1 year alongside Dublin environmental isolates and clinical isolates from patients. RAPD analysis revealed a diverse genotype, but with three major clinical isolate clusters. When the pathogenicity of clinical and Dublin isolates was compared with a random selection of Manchester isolates in a Galleria mellonella larvae model, as a group, clinical isolates were significantly more pathogenic than environmental isolates. Moreover, when relative pathogenicity of individual isolates was compared, clinical isolates were the most pathogenic, Dublin isolates were the least pathogenic and Manchester isolates showed a range in pathogenicity. Overall, this suggests that the environmental population is genetically diverse, displaying a range in pathogenicity, and that the most pathogenic strains from the environment are selected during patient infection.

Prevalence and Characteristics of Listeria monocytogenes in Bovine Colostrum in Japan

2013 ◽  
Vol 76 (2) ◽  
pp. 248-255 ◽  
Author(s):  
MEGUMI HASEGAWA ◽  
ERIKO IWABUCHI ◽  
SHIORI YAMAMOTO ◽  
HIDETAKE ESAKI ◽  
KAZUHIKO KOBAYASHI ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Dairy Farms ◽  
Pulsed Field Gel Electrophoresis ◽  
Bovine Colostrum ◽  
Pfge Type ◽  
Type Isolate ◽  
Serotype 1 ◽  
Serotype 4B

This study was conducted to determine the prevalence and characteristics of Listeria monocytogenes in bovine colostrum in Japan. We collected bovine colostrum samples from 210 dams from 21 dairy farms in Hokkaido prefecture (Japan) between March and June 2009. L. monocytogenes was detected in samples from 6 (28.6%) of the 21 farms. Of the 210 samples, 16 (7.6%) were positive for L. monocytogenes. We recovered 80 L. monocytogenes isolates; 44 (55%) isolates were classified as serotype 1/2b and 36 (45%) were classified as serotype 4b. The isolates were susceptible to penicillin, ampicillin, amoxicillin, gentamicin, kanamycin, streptomycin, erythromycin, vancomycin, tetracycline, chloramphenicol, ciprofloxacin, and trimethoprimsulfamethoxazole. Pulsed-field gel electrophoresis (PFGE) characterization of the 80 isolates revealed six PFGE types. Two PFGE types corresponded to human listeriosis cases. Most L. monocytogenes isolates possessed virulence-associated genes (actA, hly, iap, inlA, inlC, mpl, plcA, plcB, opuCA, prfA, and clpC). One PFGE type isolate possessed an epidemic clone II marker. Our findings suggest that isolates from bovine colostrum have the potential to cause human and animal listeriosis. This is the first study on the prevalence and characteristics of L. monocytogenes isolated from bovine colostrum obtained from dairy farms. Our results have important implications for improving public health and elucidating the epidemiology of L. monocytogenes in bovine colostrum.

Use of Pulsed-Field Gel Electrophoresis To Monitor a Five-Strain Mixture of Listeria monocytogenes in Frankfurter Packages†

2003 ◽  
Vol 66 (8) ◽  
pp. 1465-1468 ◽  
Author(s):  
ANNA C. S. PORTO ◽  
LAURA WONDERLING ◽  
JEFFREY E. CALL ◽  
JOHN B. LUCHANSKY
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Processing Plant ◽  
Refrigerated Storage ◽  
Pork Sausage ◽  
Pulsed Field ◽  
Potassium Lactate ◽  
Serotype 1 ◽  
Serotype 4B

In a previous study, the viability of a five-strain mixture of Listeria monocytogenes (including Scott A [serotype 4b, clinical isolate], 101M [serotype 4b, beef-pork sausage isolate], F6854 [serotype 1/2a, turkey frankfurter isolate], H7776 [serotype 4b, frankfurter isolate], and MFS-2 [serotype 1/2a, pork plant isolate]) was monitored during refrigerated storage of frankfurters prepared with and without 3.0% added potassium lactate. Throughout a 90-day period of storage at 4°C, the initial inoculum level of 20 CFU per package remained relatively constant in packages containing frankfurters prepared with potassium lactate, but pathogen counts increased to 4.6 log10 CFU in packages containing frankfurters prepared without added potassium lactate. To determine which of the five strains persisted under these conditions, randomly selected colonies obtained after 28 and 90 days of refrigerated storage of frankfurters were analyzed by pulsed-field gel electrophoresis (PFGE) with the restriction enzyme SmaI to generate distinct banding patterns for each of the five strains. Then, with the use of PFGE as a tool for identification, the percentages of the strains on days 28 and 90 of the growth study were compared. In the absence of any added potassium lactate in the product, 43% of the 58 isolates recovered on day 28 were identified as strain Scott A, 12% were identified as strain 101M, 22% were identified as strain F6854, 10% were identified as strain H7776, and 12% were identified as strain MFS-2. However, by day 90, an appreciable number (83%) of the 60 isolates analyzed were identified as strain MFS-2. In packages containing frankfurters formulated with 3.0% potassium lactate, all five strains were present at frequencies of 5 to 36% among the 19 isolates tested on day 28; however, by day 90, strain MFS-2 made up the statistical majority (63%) of the 27 isolates tested. The results of this study indicate that strain MFS-2, a serotype 1/2a isolate recovered from a pork processing plant, was more persistent than strains Scott A, 101M, F6854, or H7776 during the extended refrigerated storage of frankfurters.

scholarly journals Genomic Diversity of Listeria monocytogenes Isolated from Clinical and Non-Clinical Samples in Chile

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 396 ◽  
Author(s):  
Viviana Toledo ◽  
Henk den Bakker ◽  
Juan Hormazábal ◽  
Gerardo González-Rocha ◽  
Helia Bello-Toledo ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Severe Infection ◽  
Risk Groups ◽  
Genomic Diversity ◽  
Clinical Samples ◽  
Pathogenic Potential ◽  
Stress Survival ◽  
Sequence Types

Listeria monocytogenes is the causative agent of listeriosis, which is an uncommon but severe infection associated with high mortality rates in humans especially in high-risk groups. This bacterium survives a variety of stress conditions (e.g., high osmolality, low pH), which allows it to colonize different niches especially niches found in food processing environments. Additionally, a considerable heterogeneity in pathogenic potential has been observed in different strains. In this study, 38 isolates of L. monocytogenes collected in Chile from clinical samples (n = 22) and non-clinical samples (n = 16) were analyzed using whole genome sequencing (WGS) to determine their genomic diversity. A core genome Single Nucleotide Polymorphism (SNP) tree using 55 additional L. monocytogenes accessions classified the Chilean isolates in lineages I (n = 25) and II (n = 13). In silico, Multi-locus sequence typing (MLST) differentiated the isolates into 13 sequence types (ST) in which the most common were ST1 (15 isolates) and ST9 (6 isolates) and represented 55% of the isolates. Genomic elements associated with virulence (i.e., LIPI-1, LIPI-3, inlA, inlB, inlC, inlG, inlH, inlD, inlE, inlK, inlF, and inlJ) and stress survival (i.e., stress survival islet 1 and stress survival islet 2) were unevenly distributed among clinical and non-clinical isolates. In addition, one novel inlA premature stop codon (PMSC) was detected. Comparative analysis of L. monocytogenes circulating in Chile revealed the presence of globally distributed sequence types along with differences among the isolates analyzed at a genomic level specifically associated with virulence and stress survival.

scholarly journals Atypical Listeria monocytogenes Serotype 4b Strains Harboring a Lineage II-Specific Gene Cassette

2011 ◽  
Vol 78 (3) ◽  
pp. 660-667 ◽  
Author(s):  
Sangmi Lee ◽  
Todd J. Ward ◽  
Lewis M. Graves ◽  
Leslie A. Wolf ◽  
Kate Sperry ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Regional Distribution ◽  
Gene Cassette ◽  
The United States ◽  
Clinical Isolates ◽  
Specific Gene ◽  
Content Type ◽  
Hybridization Data ◽  
Group 3 ◽  
Serotype 4B

ABSTRACTListeria monocytogenesis the etiological agent of listeriosis, a severe food-borne illness. The population ofL. monocytogenesis divided into four lineages (I to IV), and serotype 4b in lineage I has been involved in numerous outbreaks. Several serotype 4b epidemic-associated clonal groups (ECI, -II, and -Ia) have been identified. In this study, we characterized a panel of strains of serotype 4b that produced atypical results with a serotype-specific multiplex PCR and possessed thelmo0734tolmo0739gene cassette that had been thought to be specific to lineage II. The cassette was harbored in a genomically syntenic locus in these isolates and in lineage II strains. Three distinct clonal groups (groups 1 to 3) were identified among these isolates based on single-nucleotide polymorphism-based multilocus genotyping (MLGT) and DNA hybridization data. Groups 1 and 2 had MLGT haplotypes previously encountered among clinical isolates and were composed of clinical isolates from multiple states in the United States. In contrast, group 3 consisted of clinical and environmental isolates solely from North Carolina and exhibited a novel haplotype. In addition, all group 3 isolates had DNA that was resistant to MboI, suggesting methylation of adenines at GATC sites. Sequence analysis of thelmo0734tolmo0739gene cassette from two strains (group 1 and group 3) revealed that the genes were highly conserved (>99% identity). The data suggest relatively recent horizontal gene transfer from lineage IIL. monocytogenesintoL. monocytogenesserotype 4b and subsequent dissemination among at least three distinct clonal groups ofL. monocytogenesserotype 4b, one of which exhibits restrictions in regional distribution.

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.

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