Background: The Direct Repeat locus of the Mycobacterium tuberculosis complex (MTC) is a member of the CRISPR (Clustered regularly interspaced short palindromic repeats) sequences family. Spoligotyping is the widely used PCR-based reverse-hybridization blotting technique that assays the genetic diversity of this locus and is useful both for clinical laboratory, molecular epidemiology, evolutionary and population genetics. It is easy, robust, cheap, and produces highly diverse portable numerical results, as the result of the combination of (1) Unique Events Polymorphism (UEP) (2) Insertion-Sequence-mediated genetic recombination. Genetic convergence, although rare, was also previously demonstrated. Three previous international spoligotype databases had partly revealed the global and local geographical structures of MTC bacilli populations, however, there was a need for the release of a new, more representative and extended, international spoligotyping database.
The present update on the global distribution of Mycobacterium tuberculosis complex spoligotypes provides both the octal and binary descriptions of the spoligotypes for M. tuberculosis complex, including Mycobacterium bovis, from >90 countries (13,008 patterns grouped into 813 shared types containing 11,708 isolates and 1,300 orphan patterns). A number of potential indices were developed to summarize the information on the biogeographical specificity of a given shared type, as well as its geographical spreading (matching code and spreading index, respectively). To facilitate the analysis of hundreds of spoligotypes each made up of a binary succession of 43 bits of information, a number of major and minor visual rules were also defined. A total of six major rules (A to F) with the precise description of the extra missing spacers (minor rules) were used to define 36 major clades (or families) of M. tuberculosis. Some major clades identified were the East African-Indian (EAI) clade, the Beijing clade, the Haarlem clade, the Latin American and Mediterranean (LAM) clade, the Central Asian (CAS) clade, a European clade of IS6110 low banders (X; highly prevalent in the United States and United
We present a short summary of recent observations on the global distribution of the major clades of the
Mycobacterium tuberculosis
complex, the causative agent of tuberculosis. This global distribution was defined by data-mining of an international spoligotyping database, SpolDB3. This database contains 11,708 patterns from as many clinical isolates originating from more than 90 countries. The 11,708 spoligotypes were clustered into 813 shared types. A total of 1,300 orphan patterns (clinical isolates showing a unique spoligotype) were also detected.
This study compared the hemorheological responses of a group of sickle cell trait (SCT) carriers with those of a control (Cont) group in response to 40 min of submaximal exercise (exercise intensity, 55% aerobic peak power) performed in two conditions: one with water offered ad libitum, i.e., the hydration (Hyd) condition, and one without water, i.e., the dehydration (Dehyd) condition. Blood and plasma viscosities, as well as red blood cell rigidity, were determined at rest, at the end of exercise, and at 2 h recovery with a cone plate viscometer at high shear rate and 37 degrees C. The SCT and Cont groups lost 1 +/- 0.7 and 1.6 +/- 0.6 kg of body weight, respectively, in the Dehyd condition, indicating a significant effect of water deprivation compared with the Hyd condition, in which body weight remained unchanged. Plasma viscosity increased with exercise and returned to baseline during recovery independently of the group and condition. As previously demonstrated, resting blood viscosity was greater in the SCT carriers than in the Cont group. Blood viscosity increased by the end of exercise and returned to baseline at 2 h recovery in the Cont group in both conditions. The blood viscosity of SCT carriers did not change in response to exercise in the Dehyd condition and remained elevated at 2 h recovery. This extended hyperviscosity, in association with other biological changes induced by exercise, could be considered as a risk factor for exercise-related events in SCT carriers, similar to vasoocclusive crises, notably during the recovery. In contrast, the Hyd condition normalized the hyperviscosity and red blood cell rigidity of the SCT carriers, with blood viscosity values reaching the same lower values as those found in the Cont group during the recovery. Adequate hydration of SCT carriers should be strongly promoted to reduce the clinical risk associated with potential hyperviscosity complications.
The three French overseas departments of the Americas are characterized both by insular (Guadeloupe and Martinique) and continental (French Guiana) settings with a tuberculosis case detection rate that varies from less than 10 per 100,000 per year in insular areas to an estimated incidence of more than 55 per 100,000 in French Guiana. Under a long-term genotyping program, more than three-fourths of all the Mycobacterium tuberculosis isolates (n ؍ 744) received from the three settings were fingerprinted over a 10-year period (1994 to 2003) by spoligotyping and variable number of tandem DNA repeats (VNTRs) in order to understand the current trends in their detection rates, drug resistance, and groups and subpopulations at risk of contracting the disease and to pinpoint the circulating phylogeographical clades of the bacilli. The major difference in the study populations was the nationality of the patients, with a high percentage of immigrants from highincidence neighboring countries in French Guiana and a low but increasing percentage in the French Caribbean. The rate of recent transmission was calculated to be 49.3% in French Guiana, compared to 27.2% and 16.9% in Guadeloupe and Martinique, respectively. At the phylogeographic level, 77.9% of the isolates studied belonged to four major clades (Haarlem, Latin-American and Mediterranean, T, and X) which are already reported from neighboring Caribbean islands in an international database and may underline potential interregional transmission events.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.