Molecular and Conventional Typing Methods for Listeria monocytogenes: The UK Approach

1996 ◽  
Vol 59 (10) ◽  
pp. 1102-1105 ◽  
Author(s):  
J. McLAUCHLIN
Keyword(s):  
Listeria Monocytogenes ◽  
Fragment Length Polymorphism ◽  
Work Load ◽  
Polymorphism Analysis ◽  
Laboratory Service ◽  
The Public ◽  
Dna Restriction ◽  
Typing Methods ◽  
The Uk ◽  
Index Of Diversity

Subtyping systems for Listeria monocytogenes have proved to be of great use in the elucidation of the epidemiology of listeriosis. Considerations for devising strategies to subtype this organism are discussed, together with the surveillance methods, work load, and resources used by the Public Health Laboratory Service in London (England). A combination of both molecular and conventional typing methods are currently in use, and these comprise the established techniques of serotyping, phage-typing, and DNA restriction-fragment length polymorphism analysis, together with the experimental procedures of resistance to arsenite and cadmium and the detection of plasmid DNA. The efficacy of this approach is assessed using Simpson's index of diversity.

scholarly journals High-Resolution Genotyping of Streptococcus pyogenesSerotype M1 Isolates by Fluorescent Amplified-Fragment Length Polymorphism Analysis

1999 ◽  
Vol 37 (6) ◽  
pp. 1948-1952 ◽  
Author(s):  
Meeta Desai ◽  
Androulla Efstratiou ◽  
Robert George ◽  
John Stanley
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Geographic Origin ◽  
Amplified Fragment Length Polymorphism ◽  
Discriminatory Power ◽  
Polymorphism Analysis ◽  
Worldwide Distribution ◽  
High Discriminatory Power ◽  
Typing Methods

We have used fluorescent amplified-fragment length polymorphism (FAFLP) analysis to subtype clinical isolates of Streptococcus pyogenes serotype M1. Established typing methods define most M1 isolates as members of a clone that has a worldwide distribution and that is strongly associated with invasive diseases. FAFLP analysis simultaneously sampled 90 to 120 loci throughout the M1 genome. Its discriminatory power, precision, and reproducibility were compared with those of other molecular typing methods. Irrespective of disease symptomatology or geographic origin, the majority of the clinical M1 isolates shared a single ribotype, pulsed-field gel electrophoresis macrorestriction profile, and emm1 gene sequence. Nonetheless, among these isolates, FAFLP analysis could differentiate 17 distinct profiles, including seven multi-isolate groups. The FAFLP profiles of M1 isolates reproducibly exhibited between 1 and more than 20 amplified fragment differences. The high discriminatory power of genotyping by FAFLP analysis revealed genetic microheterogeneity and differentiated otherwise “identical” M1 isolates as members of a clone complex.

scholarly journals Listeria monocytogenes Isolates from Foods and Humans Form Distinct but Overlapping Populations

2004 ◽  
Vol 70 (10) ◽  
pp. 5833-5841 ◽  
Author(s):  
Michael J. Gray ◽  
Ruth N. Zadoks ◽  
Esther D. Fortes ◽  
Belgin Dogan ◽  
Steven Cai ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Plaque Assay ◽  
Virulence Gene ◽  
The United States ◽  
Polymorphism Analysis ◽  
Genetic Lineages ◽  
The Public ◽  
Cell Spread ◽  
Specific Food

ABSTRACT A total of 502 Listeria monocytogenes isolates from food and 492 from humans were subtyped by EcoRI ribotyping and PCR-restriction fragment length polymorphism analysis of the virulence gene hly. Isolates were further classified into genetic lineages based on subtyping results. Food isolates were obtained through a survey of selected ready-to-eat food products in Maryland and California in 2000 and 2001. Human isolates comprised 42 isolates from invasive listeriosis cases reported in Maryland and California during 2000 and 2001 as well as an additional 450 isolates from cases that had occurred throughout the United States, predominantly from 1997 to 2001. Assignment of isolates to lineages and to the majority of L. monocytogenes subtypes was significantly associated with the isolate source (food or human), although most subtypes and lineages included both human and food isolates. Some subtypes were also significantly associated with isolation from specific food types. Tissue culture plaque assay characterization of the 42 human isolates from Maryland and California and of 91 representative food isolates revealed significantly higher average infectivity and cell-to-cell spread for the human isolates, further supporting the hypothesis that food and human isolates form distinct populations. Combined analysis of subtype and cytopathogenicity data showed that strains classified into specific ribotypes previously linked to multiple human listeriosis outbreaks, as well as those classified into lineage I, are more common among human cases and generate larger plaques than other subtypes, suggesting that these subtypes may represent particularly virulent clonal groups. These data will provide a framework for prediction of the public health risk associated with specific L. monocytogenes subtypes.

scholarly journals Repeated Recovery ofStaphylococcus saprophyticusFrom the Urogenital Tracts of Women: Persistence Vs. Recurrence

1995 ◽  
Vol 2 (5) ◽  
pp. 218-222 ◽  
Author(s):  
M. E. Rupp ◽  
J. Han ◽  
R. V. Goering
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Restriction Fragment Length Polymorphism ◽  
Tract Infection ◽  
Gel Electrophoresis ◽  
Fragment Length Polymorphism ◽  
Chromosomal Dna ◽  
Dna Restriction ◽  
Typing Methods ◽  
Restriction Fragment Length

Objective:The purpose of this study was to determine whether colonization was persistent or recurrent in a small group of women who had repeated recovery ofStaphylococcus saprophyticusfrom their urogenital tracts.Methods:Paired isolates ofS. saprophyticusfrom each of the study subjects were genotypically typed by plasmid fingerprinting and comparison of chromosomal-DNA restriction fragment-length polymorphism patterns by field-inversion gel electrophoresis (FIGE) and contour-clamped homogenous electric-field (CHEF) electrophoresis.Results:All isolates ofS. saprophyticusfrom the study subjects were classified as genetically unique by each of the typing methods.Conclusions:The subjects experienced recurrent colonization with different isolates ofS. saprophyticus.These findings may have broader implications regarding the pathogenesis and recurrence ofS. saprophyticusurinary-tract infection.

Undernotification of tuberculosis in patients with AIDS

1996 ◽  
Vol 7 (1) ◽  
pp. 58-59 ◽  
Author(s):  
M A Balogun ◽  
P G Wall ◽  
A Noone
Keyword(s):  
Public Health ◽  
Hiv Infection ◽  
Clinical Management ◽  
Local Authority ◽  
Aids Patients ◽  
Patient Confidentiality ◽  
Laboratory Service ◽  
The Public ◽  
Statutory Requirement ◽  
The Uk

The purpose of this study was to establish the extent of undernotification of tuberculosis in AIDS patients resident in 2 inner London local authorities. For residents of the 2 authorities, statutory notifications of tuberculosis between 1986 and 1992 were compared, using soundex codes of surnames, sex and year of birth, with AIDS cases reported to the Public Health Laboratory Service (PHLS) AIDS Centre during the same period where TB had been recorded on the AIDS report form. In 36 of 613 AIDS cases reported as residents of the 2 authorities tuberculosis was recorded on the AIDS report form. Matching revealed that only 2 (6%) of these cases had been notified to the local authority. These results highlight the need to resolve the dilemma between concerns about patient confidentiality and the statutory requirement to notify tuberculosis so that clinical management of contacts can be undertaken and the true impact of HIV infection on the incidence of tuberculosis in the UK can be elucidated.

Relatedness of three species of Agaricus inferred from restriction fragment length polymorphism analysis of the ribosomal DNA repeat and mitochondrial DNA

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 173-178 ◽  
Author(s):  
William E. A. Hintz ◽  
James B. Anderson ◽  
Paul A. Horgen
Keyword(s):  
Mitochondrial Dna ◽  
Restriction Fragment Length Polymorphism ◽  
Restriction Site ◽  
Fragment Length Polymorphism ◽  
The Other ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Restriction Patterns ◽  
Dna Restriction ◽  
Restriction Fragment Length

The ribosomal DNA (rDNA) repeat of Agaricus brunnescens (= A. bisporus) was cloned and mapped for six restriction endonucleases. The map positions of the 26S, 18S, and 5.8S rRNA genes on the 9.2 kilo base pairs (kbp) repeat were determined by alignment of sites conserved in the rRNA genes of other fungi. The rDNA restriction site maps for six isolates of A. brunnescens, five isolates of A. bitorquis, and three isolates of A. campestris were compared using cloned A. brunnescens (Ag 50) rDNA as a hybridization probe. The rDNA restriction patterns for all six A. brunnescens isolates were identical. The A. bitorquis and A. campestris isolates were subdivided into two groups each, according to rDNA restriction-site polymorphisms. The A. brunnescens and A. bitorquis rDNAs were distinguished by a 0.7 kbp length difference in the noncoding spacer between the 18S and 26S rRNA genes. Despite the almost perfect conservation of the coding region between species, the noncoding spacers of A. campestris and the other two Agaricus species were too divergent to propose a simple series of mutational events to account for the differences. Interstrain and interspecies variation in the mitochondrial DNA was also surveyed. Strain-specific mitochondrial DNA restriction patterns were recognized and fewer differences were observed between the A. brunnescens and A. bitorquis isolates than between A. campestris and the other two species.Key words: Agaricus brunnescens (= A. bisporus), Agaricus, rDNA, mitochondrial DNA, restriction fragment length polymorphism analysis.

scholarly journals Randomly amplified polymorphic DNA typing: a useful tool for rapid epidemiological typing ofKlebsiella pneumoniae

1994 ◽  
Vol 113 (3) ◽  
pp. 445-454 ◽  
Author(s):  
N. A. C. S. Wong ◽  
C. J. Linton ◽  
H. Jalal ◽  
M. R. Millar
Keyword(s):  
Gel Electrophoresis ◽  
Extraction Method ◽  
Fragment Length Polymorphism ◽  
Dna Typing ◽  
Pulsed Field Gel Electrophoresis ◽  
Polymorphism Analysis ◽  
Randomly Amplified Polymorphic Dna ◽  
Epidemiological Typing ◽  
Dna Extraction Method ◽  
Typing Methods

SUMMARYDiscriminatory typing methods are invaluable in the investigation of outbreaks of infectious diseases. Single primers were used to generate randomly amplified polymorphic DNA (RAPD) profiles fromKlebsiella pneumoniaeisolates of various serotype andK. pneumoniaeisolates from cases of sepsis at a Malaysian hospital and two English hospitals. RAPD profiles of acceptable reproducibility, a maximum of three minor band variations, were produced using a rapid DNA extraction method. RAPD typing ofK. pneumoniaewas shown to be as discriminatory as restriction fragment length polymorphism analysis using pulsed field gel electrophoresis yet quicker and less costly. The findings suggest that RAPD typing may be a useful tool for the epidemiological typing ofK. pneumoniae.

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