scispace - formally typeset
Search or ask a question
Topic

Typing

About: Typing is a research topic. Over the lifetime, 5010 publications have been published within this topic receiving 146539 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the authors applied multiple locus variable number of tandem repeats analysis (MLVA) for surveillance typing of S. Typhimurium since 2004 and found that the results revealed that an isolate from a pig herd and its corresponding slaughterhouse located in the same geographic region as the outbreak had the same PFGE and MLVA type as the human isolates.
Abstract: In Denmark, as part of the national laboratory-based surveillance system of human enteric infections, all S. Typhimurium isolates are currently sub-typed using phage typing, antibiogram typing, and pulsed-field gel electrophoresis (PFGE). However, the discriminatory ability of PFGE is not always high enough to discriminate within certain phage types, and it is not always possible to separate unrelated and related isolates. We have therefore applied multiple locus variable number of tandem repeats analysis (MLVA) for surveillance typing of S. Typhimurium since 2004. In May and June 2005, an outbreak with 26 cases of S. Typhimurium infection was identified by MLVA. The isolates were fully sensitive and had one of the most frequently occurring Danish phage types (DT12) and PFGE types. S. Typhimurium DT12 isolates from routine surveillance of animals and food were typed using MLVA and PFGE for comparison with the human isolates. The typing results revealed that an isolate from a pig herd and its corresponding slaughterhouse located in the same geographic region as the outbreak had the same PFGE and MLVA type as the human isolates. In contrast, all other DT12 isolates investigated, which had the same PFGE profile, had different MLVA types. The conclusion that the pig herd was the source of the human infections was supported by patient information, and pork from the herd stopped entering the market on 29 June. MLVA may contribute significantly to both surveillance and outbreak investigations of S. Typhimurium, as without MLVA typing this outbreak would not have been found nor its origin traced.

43 citations

Journal ArticleDOI
TL;DR: Evidence that the extensive diversity that was found in Helicobacter pylori flagellin genes flaA and flaB is the result of reassortment of sequences between strains in the bacterial population is presented, such that a comparatively small number of individual sequence mutations can recombine together in random combinations to form a greater number of distinct alleles.
Abstract: Extensive DNA sequence diversity was noted in Helicobacter pylori flagellin genes flaA and flaB. PCR amplified sequences from 49 isolates were digested with AluI, HindIII, MboI or MspI, the resultant patterns were compared between the different isolates and these used to differentiate the isolates from each other. Evidence that the extensive diversity that was found in these genes is the result of reassortment of sequences between strains in the bacterial population is presented, such that a comparatively small number of individual sequence mutations can recombine together in random combinations to form a greater number of distinct alleles. Geographical differences in the predominant patterns in the flaA alleles were also observed and could reflect regional differences either in the human host population or in the bacterial population. In view of the genetic complexity of this species, molecular typing schemes designed to identify related strains may falsely associate strains if the methods do not characterize sufficient genetic sites to exclude chance associations of genetic markers in strains which are actually not closely related to each other.

43 citations

Journal ArticleDOI
TL;DR: A multilocus sequence typing (MLST) scheme, comprised of seven single-copy housekeeping genes, is introduced to genetically characterize Trichomonas vaginalis, revealing a diverse T. vaginalis population.
Abstract: In this study, we introduce a multilocus sequence typing (MLST) scheme, comprised of seven single-copy housekeeping genes, to genetically characterize Trichomonas vaginalis. Sixty-eight historical and recent isolates of T. vaginalis were sampled from the American Type Culture Collection and female patients at area health care facilities, respectively, to assess the usefulness of this typing method. Forty-three polymorphic nucleotide sites, 51 different alleles, and 60 sequence types were distinguished among the 68 isolates, revealing a diverse T. vaginalis population. Moreover, this discriminatory MLST scheme retains the ability to identify epidemiologically linked isolates such as those collected from sexual partners. Population genetic and phylogenetic analyses determined that T. vaginalis population structure is strongly influenced by recombination and is composed of two separate populations that may be nonclonal. MLST is useful for investigating the epidemiology, genetic diversity, and population structure of T. vaginalis.

43 citations

Journal ArticleDOI
TL;DR: Amplified fragment length polymorphism (AFLP) was used to type 34 strains of Mycoplasma gallisepticum including vaccine strains ts-11, 6/85, and F. Rossi, able to identify and differentiate both MG field strains from recent outbreaks and those that were epidemiologically related.
Abstract: Amplified fragment length polymorphism (AFLP) was used to type 34 strains of Mycoplasma gallisepticum (MG) including vaccine strains ts-11, 6/85, and F. Using AFLP, a total of 10 groups, with 30 distinguishable AFLP typing profiles, were generated in the analysis. The AFLP method was able to identify and differentiate both MG field strains from recent outbreaks and those that were epidemiologically related. The AFLP procedure will provide assistance in identifying the sources of mycoplasma infections. Vaccine strains were also differentiated from other field strains, which will be useful in the evaluation of vaccination programs. The AFLP discrimination potential was compared to other molecular typing techniques such as gene-targeted typing by DNA sequence analysis of the MG cytadhesin-like protein encoding gene, mgc2, and random amplified polymorphic DNA assay on the same MG isolates. The three assays correlated well with one another, with AFLP analysis having a much higher discriminatory power and reproducibility.

43 citations

Book ChapterDOI
TL;DR: This chapter provides an overview of the SSO and SSP methods in relation to HLA typing.
Abstract: Human leukocyte antigen (HLA) typing, utilising the sequence-specific oligonucleotide (SSO) and sequence-specific primer (SSP) technologies, has been in routine use in many tissue typing laboratories worldwide for more than 20 years since the development of the polymerase chain reaction. Both methods are very useful for clinical and research purposes and can provide generic (low resolution) to allelic (high resolution) typing results. This chapter provides an overview of the SSO and SSP methods in relation to HLA typing.

43 citations


Network Information
Related Topics (5)
Antibody
113.9K papers, 4.1M citations
81% related
Antigen
170.2K papers, 6.9M citations
80% related
Virulence
35.9K papers, 1.3M citations
80% related
Virus
136.9K papers, 5.2M citations
78% related
Plasmid
44.3K papers, 1.9M citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023329
2022690
2021145
2020126
2019136
2018147