Use of automated ribotyping of Austrian Listeria monocytogenes isolates to support epidemiological typing

1999 ◽  
Vol 35 (3) ◽  
pp. 237-244 ◽  
Author(s):  
Franz Allerberger ◽  
Scott J Fritschel
Keyword(s):  
Listeria Monocytogenes ◽  
Epidemiological Typing ◽  
Automated Ribotyping

Enhanced Detection of Listeria spp. in Farmstead Cheese Processing Environments through Dual Primary Enrichment, PCR, and Molecular Subtyping

2008 ◽  
Vol 71 (11) ◽  
pp. 2239-2248 ◽  
Author(s):  
DENNIS J. D'AMICO ◽  
CATHERINE W. DONNELLY
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Samples ◽  
Environmental Sampling ◽  
Strain Diversity ◽  
Enrichment Protocol ◽  
Automated Ribotyping ◽  
Epidemiological Significance ◽  
Enrichment Methods ◽  
Over Time ◽  
Higher Sensitivity

The incidence and ecology of Listeria spp. in farmstead cheese processing environments were assessed through environmental sampling conducted in nine different plants over a 10-week period. Environmental samples (n = 705) were examined for the presence of Listeria spp. by using three detection/isolation protocols. The use of dual enrichment methods, which allowed for the recovery of injured Listeria spp. (mUSDA), identified more Listeria species–positive samples with higher sensitivity than the standard USDA method. The addition of PCR to the mUSDA method identified the most Listeria monocytogenes–positive samples, achieving greater sensitivity of detection while substantially reducing time. Overall, 7.5% of samples were positive for Listeria spp., yielding 710 isolates, 253 of which were subtyped by automated ribotyping to examine strain diversity within and between plants over time. The isolation of specific ribotypes did not appear to be affected by the enrichment protocol used. Fifteen (2.1%) samples yielded L. monocytogenes isolates differentiated almost equally into ribotypes of lineages I and II. Of most concern was the persistent and widespread contamination of a plant with L. monocytogenes DUP-1042B, a ribotype previously associated with multiple outbreaks of listeriosis. Our results suggest that the extent of contamination by Listeria spp., notably L. monocytogenes, in farmstead cheese plants is comparatively low, especially for those with on-site farms. The results of this study also identified points of control for use in designing more effective Listeria spp. control and monitoring programs with a focus on ribotypes of epidemiological significance.

scholarly journals Sensitivity of Listeria monocytogenes to Sanitizers Used in the Meat Processing Industry

2002 ◽  
Vol 68 (12) ◽  
pp. 6405-6409 ◽  
Author(s):  
Nadya Romanova ◽  
Stacy Favrin ◽  
Mansel W. Griffiths
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Efflux Pump ◽  
Pulsed Field Gel Electrophoresis ◽  
Meat Processing ◽  
Processing Industry ◽  
Automated Ribotyping ◽  
Plasmid Profiling ◽  
The Relationship ◽  
Ammonium Compounds

ABSTRACT Nineteen Listeria monocytogenes strains were characterized by automated ribotyping, pulsed-field gel electrophoresis, and plasmid profiling to determine the relationship between genotype and sanitizer resistance. Isolates within a ribogroup had a consistent sensitivity or resistance phenotype except for ribogroup C isolates. All isolates with resistance phenotypes harbored two plasmids. The sensitivity of L. monocytogenes strains to quaternary ammonium compounds (QACs) was correlated with sensitivity to sanitizers and antibiotics with other modes of action. All isolates tested contained the mdrL gene, which encodes an efflux pump that confers resistance to QACs and is both chromosome and plasmid borne.

International Life Sciences Institute North America Listeria monocytogenes Strain Collection: Development of Standard Listeria monocytogenes Strain Sets for Research and Validation Studies

2006 ◽  
Vol 69 (12) ◽  
pp. 2929-2938 ◽  
Author(s):  
ERIC FUGETT ◽  
ESTHER FORTES ◽  
CATHERINE NNOKA ◽  
MARTIN WIEDMANN
Keyword(s):  
Listeria Monocytogenes ◽  
Research And Development ◽  
Foodborne Pathogens ◽  
Validation Studies ◽  
Relevant Information ◽  
Listeria Innocua ◽  
Molecular Subtyping ◽  
Strain Collection ◽  
Source Data ◽  
Automated Ribotyping

Research and development efforts on bacterial foodborne pathogens, including the development of novel detection and subtyping methods, as well as validation studies for intervention strategies can greatly be enhanced through the availability and use of standardized strain collections. These types of strain collections are available for some foodborne pathogens, such as Salmonella and Escherichia coli. We have developed a standard Listeria monocytogenes strain collection that has not been previously available. The strain collection includes (i) a diversity set of 25 isolates chosen to represent a genetically diverse set of L. monocytogenes isolates as well as a single hemolytic Listeria innocua strain and (ii) an outbreak set, which includes 21 human and food isolates from nine major human listeriosis outbreaks that occurred between 1981 and 2002. The diversity set represents all three genetic L. monocytogenes lineages (I, n = 9; II, n = 9; and III, n = 6) as well as nine different serotypes. Molecular subtyping by EcoRI automated ribotyping and pulsed-field gel electrophoresis (PFGE) with AscI and ApaI separated the 25 isolates in the diversity set into 23 ribotypes and 25 PFGE types, confirming that this isolate set represents considerable genetic diversity. Molecular subtyping of isolates in the outbreak set confirmed that human and food isolates were identical by ribotype and PFGE, except for human and food isolates for two outbreaks, which displayed related but distinct PFGE patterns. Subtype and source data for all isolates in this strain collection are available on the Internet and are linked to the PathogenTracker database (www.pathogentracker.com), which allows the addition of new, relevant information on these isolates, including links to publications that have used isolates from this collection. We have thus developed a core L. monocytogenes strain collection, which will provide a resource for L. monocytogenes research and development efforts with centralized Internet-based data curation and integration.

scholarly journals Computer-Assisted Analysis and Epidemiological Value of Genotyping Methods for Campylobacter jejuni andCampylobacter coli

2000 ◽  
Vol 38 (5) ◽  
pp. 1940-1946 ◽  
Author(s):  
Paulo de Boer ◽  
Birgitta Duim ◽  
Alan Rigter ◽  
Jan van der Plas ◽  
Wilma F. Jacobs-Reitsma ◽  
...  
Keyword(s):  
Data Analysis ◽  
Computer Assisted ◽  
Aflp Analysis ◽  
Aflp Fingerprinting ◽  
Epidemiological Typing ◽  
Typing Method ◽  
Different Types ◽  
Typing Methods ◽  
Automated Ribotyping ◽  
Assisted Analysis

For epidemiological tracing of the thermotolerantCampylobacter species C. jejuni and C. coli, reliable and highly discriminatory typing techniques are necessary. In this study the genotyping techniques of flagellin typing (flaA typing), pulsed-field gel electrophoresis (PFGE), automated ribotyping, and amplified fragment length polymorphism (AFLP) fingerprinting were compared. The following aspects were compared: computer-assisted analysis, discriminatory power, and use for epidemiological typing of campylobacters. A set of 50 campylobacter poultry isolates from The Netherlands and neighboring countries was analyzed. Computer-assisted analysis made cluster analysis possible and eased the designation of different genotypes. AFLP fingerprinting was the most discriminatory technique, identifying 41 distinct genotypes, while PFGE identified 38 different types, flaA typing discriminated 31 different types, and ribotyping discriminated 26 different types. Furthermore, AFLP analysis was the most suitable method for computer-assisted data analysis. In some cases combining the results of AFLP fingerprinting, PFGE, and flaA typing increased our ability to differentiate strains that appeared genetically related. We conclude that AFLP is a highly discriminatory typing method and well suited for computer-assisted data analysis; however, for optimal typing of campylobacters, a combination of multiple typing methods is needed.

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