Typing

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

Intrafamilial, Preferentially Mother-to-Child and Intraspousal, Helicobacter pylori Infection in Japan Determined by Mutilocus Sequence Typing and Random Amplified Polymorphic DNA Fingerprinting

Abstract: Background The infection route of Helicobacter pylori has been recognized to be mainly intrafamilial, preferentially mother-to-child, especially in developed countries. To determine the transmission route, we examined whether multilocus sequence typing (MLST) was useful for analysis of intrafamilial infection. The possibility of intraspousal infection was also evaluated. Materials and Methods Clonal relationships between strains derived from 35 index Japanese pediatric patients, and their family members were analyzed by two genetic typing procedures, MLST and random amplified polymorphic DNA (RAPD) fingerprinting. Results Mostly coincident results were obtained by MLST and RAPD. By MLST, the allele of loci in the isolates mostly matched between the index child and both the father and mother for 9 (25.7%) of the 35 patients, between the index child and the mother for 25 (60.0%) of the 35 patients. Conclusions MLST is useful for analyzing the infection route of H. pylori as a highly reproducible method. Intrafamilial, especially mother-to-children and sibling, infection is the dominant transmission route. Intraspousal infection is also thought to occur in about a quarter in the Japanese families.

Sequence-Based Human Leukocyte Antigen—B Typing of Patients Infected with Ebola Virus in Uganda in 2000: Identification of Alleles Associated with Fatal and Nonfatal Disease Outcomes

Abstract: The Sudan species of Ebola virus (SEBOV) causes severe, often fatal infection in approximately 50% of infected humans. We sought to determine whether the human leukocyte antigen-B (HLA-B) locus has a role in the outcome of SEBOV disease by typing 77 cases from an outbreak in northern Uganda in 2000-2001. Sequence-based HLA-B typing was performed using leukocytes isolated from 77 patients. Statistical analysis and a predictive discriminant analysis (PDA) were applied to typing data. Epitope prediction software was also applied to SEBOV sequences. Statistically significant associations were found between certain sets of alleles and either fatal or nonfatal disease outcomes. Alleles B*67 and B*15 were associated with fatal outcomes, whereas B*07 and B*14 were associated with nonfatal outcomes. The PDA-derived functions that were produced were 81.8% accurate in classifying patients into their correct outcome group. Several epitopes predicted to bind strongly to HLA-B*07 molecules were identified in the viral polymerase, nucleoprotein, and VP35 protein. HLA-B alleles associated with either fatal or nonfatal outcomes of SEBOV disease were identified and can be used in a predictive model. Studies of HLA-B-restricted epitopes could contribute to characterization of protective host responses and to vaccine development.

Genetic Diversity of Mycobacterium tuberculosis in Sicily Based on Spoligotyping and Variable Number of Tandem DNA Repeats and Comparison with a Spoligotyping Database for Population-Based Analysis

Abstract: In a previous study, we proposed to associate spoligotyping and typing with the variable number of tandem DNA repeats (VNTR) as an alternative strategy to IS6110-restriction fragment length polymorphism (RFLP) for molecular epidemiological studies on tuberculosis. The aim of the present study was to further evaluate this PCR-based typing strategy and to describe the population structure of Mycobacterium tuberculosis in another insular setting, Sicily. A collection of 106 DNA samples from M. tuberculosis patient isolates was characterized by spoligotyping and VNTR typing. All isolates were independently genotyped by the standard IS6110-RFLP method, and clustering results between the three methods were compared. The totals for the clustered isolates were, respectively, 15, 60, and 82% by IS6110-RFLP, spoligotyping, and VNTR typing. The most frequent spoligotype included type 42 that missed spacers 21 to 24 and spacers 33 to 36 and derived types 33, 213, and 273 that, together represented as much as 26% of all isolates, whereas the Haarlem clade of strains (types 47 and 50, VNTR allele 32333) accounted for 9% of the total strains. The combination of spoligotyping and VNTR typing results reduced the number of clusters to 43% but remained superior to the level of IS6110-RFLP clustering (ca. 15%). All but one IS6110-defined cluster were identified by the combination of spoligotyping and VNTR clustering results, whereas 9 of 15 spoligotyping-defined clusters could be further subdivided by IS6110-RFLP. Reinterpretation of previous IS6110-RFLP results in the light of spoligotyping-VNTR typing results allowed us to detect an additional cluster that was previously missed. Although less discriminative than IS6110-RFLP, our results suggest that the use of the combination of spoligotyping and VNTR typing is a good screening strategy for detecting epidemiological links for the study of tuberculosis epidemiology at the molecular level.