Marcel A Behr

..Although M. avium is known for its genetic plasticity, these observations also show that strains of the pathogen can be genotypically stable over extended time periods...

..To assign when foreign genes were likely acquired, we designed a bioinformatic program called mycoHIT (mycobacterial homologue investigation tool) to analyze these data in conjunction with the MLSA-based phylogeny...

..Understanding differences within the M. tuberculosis complex and the evolutionary forces shaping these differences is important for investigating the basis of its success as both a symbiont and a pathogen...

..In most of the world, microbiologic diagnosis of tuberculosis (TB) is limited to microscopy. Recent guidelines recommend culture-based diagnosis where feasible...

..Continuing research is attempting to assess the effect of these genetic alterations on properties of BCG strains, with the goals of suggesting the ideal BCG for vaccination and providing avenues for improvement on existing BCG vaccines...

..In this review, we discuss the current understanding of mycobacterial and Crohn's genetic susceptibility and review the evidence that NOD2/CARD15 may mediate host resistance to mycobacterial infection...

..Genomic deletions therefore provide a new opportunity to accurately classify organisms for diagnostic and epidemiologic purposes, serving as the basis for further study of the natural variability across MTC organisms...

..This article reviews published contributions that directly or indirectly address this question...

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..tuberculosis, potentially explaining the sequence of genomic events that originally permitted an environmental mycobacterium to evolve into a host-associated pathogen...

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..tuberculosis delta sigK rskA. Together, our data indicate that the regulatory system SigK/RskA is conserved across the Mycobacterium genus, whereas the regulon under its control varies considerably across species...

..These results serve as a baseline for potency studies of different preparations and should aid in comparative studies of newly discovered antigens for the diagnosis of infection and disease by M. avium complex organisms...

..However, genotyping suggested substantial, previously unrecognized transmission to children despite low overall incidence...

..Furthermore, comparative transcriptomics reveals the concurrent down-regulation of several gene neighborhoods beyond RD1. The potential relevance of these other expression changes towards MTB virulence is discussed...

..We propose a simple PCR-based strategy based on these polymorphisms that can rapidly type M. avium isolates into these subgroups...

..avium subsets in isolation, it is expected that attention to the similarities and differences between M. avium organisms will provide greater insight into their fundamental differences, including their propensity to cause disease...

..We believe that this independent validation of the LSP method should encourage researchers to adopt this system in investigations aimed at elucidating the role of strain variation in TB...

..In conclusion, M. avium subsp. hominissuis represents a diverse group of organisms from which two pathogenic clones (M. avium subsp. paratuberculosis and M. avium subsp. avium/M. avium subsp. silvaticum) have evolved independently...

..Newfound deletions from the dassie bacillus are discussed in relation to their evolutionary and biological significance...

..paratuberculosis in tissue is governed more by bacterial burden than by staining method...

..paratuberculosis isolates revealed that IS900 is highly conserved, with only two sequevars distinguishing sheep and cattle lineages. Amplification of IS900-like sequences is not sufficient as a proxy for M. avium subsp. paratuberculosis...

..This high degree of adaptation of host genetics to strain-specific pathogenesis is expected to provide a suitable framework for the selection of specific host-mycobacteria combinations during co-evolution of mycobacteria with humans...

..avium subsp. paratuberculosis...

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..Some reports have associated certain lineages with particular clinical phenotypes, but there is still insufficient information regarding the clinical and epidemiologic implications of MTB lineage variation...

..These data demonstrate that a mutation of sigK is responsible for decreased expression of MPB70 and MPB83 in low-producing BCG strains and provide clues into the role of Mycobacterium tuberculosis SigK...

..Taken together, these data indicate that NOD2 mediates resistance to mycobacterial infection via both innate and adaptive immunity...

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..A unique profile for M. avium subsp. silvaticum was not obtained. These results indicate that sequencing the 3' region of the hsp65 gene can simply and unambiguously distinguish species and subspecies of the M. avium complex...

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..9/100,000. The objectives of this study were to describe the epidemiology of TB among homeless persons in Montreal and assess patterns of transmission and sharing of key locations...

..Overall, the results demonstrated the importance of considering the joint effects of the mycobacterial and host genetic backgrounds on susceptibility to mycobacterial infections...

..avium subsp. paratuberculosis and may serve as a general model for the origin of pathogenic mycobacteria...

..Together these findings indicate that Rv0444c encodes the regulator of SigK (RskA) and mutations in this gene explain high-level MPT70/MPT83 expression by certain MTC members...

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..Using two assays in two settings, presence of M. avium organisms was strongly associated with Crohn's disease...

..We show that these genes form a bicistronic operon regulated by Rv1773, a transcriptional repressor deleted during the in vitro evolution of BCG...

..We also discuss how one must carefully interpret any inferences that arise from a combination of continuous and dichotomous tests...

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..As none of these strains was marked by the deletion of RD9, we conclude that M. africanum and other atypical members of the M. tuberculosis complex are decidedly uncommon in this part of Africa...

..These data highlight the need to evaluate these regions across a diverse panel of clinical and environmental isolates and indicate the LSPs best suited for M. avium subsp. paratuberculosis diagnostics...

..From this, a phylogenetic stratification of genotypes offers a predictive framework upon which to base future genetic and phenotypic studies of the MTC...

..In a resource-rich country such as Canada, these communities illustrate some of the persistent challenges of TB control and elimination...

..tuberculosis remained viable during this process. These data suggest that the extraction of M. tuberculosis DNA should be performed within containment until complete...

..Our results demonstrate that the loss of methoxymycolic acid production did not apparently affect the virulence of BCG strains...

..tuberculosis complex subspecies. The contrast between the two modes of evolution are discussed in its relevance towards TB pathogenicity...

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..CM resistance in Jak3(W81R/+) heterozygotes occurs in presence of normal T, B and NK cell numbers. These findings highlight the pathological role of CD8(+) T cells and Jak3-dependent IFN-γ-mediated Th1 responses in CM pathogenesis...

..Finally, it discusses the current genomic evidence regarding the origin and evolution of M. tuberculosis in the context of its relevance for tuberculosis control in humans and other mammalian hosts...

..Our findings indicate that N-glycolyl MDP has a greater NOD2-stimulating activity than N-acetyl MDP, consistent with the historical observation attributing exceptional immunogenic activity to the mycobacterial cell wall...

..Attention is drawn towards the impact of comparative genomics in generating several exciting hypotheses towards diagnosis, epidemiology, and prevention of tuberculosis disease...

..Hospital exposures were associated with changes in the intestinal microbiota and risk of CDAD, and these changes were not driven exclusively by antimicrobial use...

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..The data provide compelling evidence that human tuberculosis did not originate from the present-day bovine form. Genomic deletions present themselves as an attractive modality to study the evolution of the M. tuberculosis complex...

..Madhu Pai and colleagues introduce the BCG World Atlas, an open access, user friendly Web site for TB clinicians to discern global BCG vaccination policies and practices and improve the care of their patients...

..We also identify crucial research questions required to advance towards assessing the causal role of candidate microbes in the aetiopathogenesis of Crohn's disease...

..We conclude that a clonally related family of PZA-monoresistant M. tuberculosis isolates in Quebec represents historic rather than recent transmission...

..Therefore, it was concluded that genes within or controlled by RD1 are essential for MTB virulence and that loss of RD1 was important in BCG attenuation...

..tuberculosis complex tree in between classical M. tuberculosis and classical M. bovis. These observations are discussed in their significance in M. tuberculosis complex classification...

..We recommend that ongoing surveillance and treatment programmes be directed towards this community...

..Furthermore, the combined findings suggest that early BCG vaccines may even be superior to the later ones that are more widely used...

..A logical start is to determine the within-person variability of T-cell responses during serial testing...

..bovis BCG strains. This raises the possibility that a contributing factor to the attenuation of BCG strains may be an inability of this global regulator to control the expression of genes required for in vivo survival and persistence...

..The proportion of transmission in the community that took place in the household was 19%, and therefore, in this high-incidence area, tuberculosis transmission occurs mainly outside the household...

..tuberculosis cultures in diagnostic laboratories with limited financial resources, but with competent technologists...

..These results suggest that BCG strains are limited in nitrogen metabolic capacity and predict defects that may restrict multiplication and persistence of the live vaccine within the host...

..In a high-tuberculosis (TB) incidence area of Cape Town, South Africa, there is a very high rate of unexplained recurrent TB. The incidence of new bacteriologically confirmed disease in the area is 313 per 100,000 individuals...

..The objective of this study was to identify risk factors for ongoing community transmission of tuberculosis (TB) in two densely populated urban communities with a high incidence rate of TB in Cape Town, South Africa...