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Molecular characterisation and immunological analysis of clinical and environmental isolates of Mycobacterium kansasii from South African gold minesKwenda, Geoffrey 31 March 2011 (has links)
PhD, Faculty of Health Sciences, University of the Witwatersrand / The South African gold-mining workforce has an unusually high incidence of Mycobacterium kansasii disease, yet little is known about the possible sources of M. kansasii
infection, genetic diversity and the basis for this organism’s pathogenicity. The purpose of
this study was to investigate these issues in a gold-mining environment. Five M. kansasii
isolates and 10 other potentially pathogenic mycobacteria were cultured mainly from
showerhead biofilms. PCR-restriction analysis (PRA) of the hsp65 gene on 191 clinical and
on the 5 environmental M. kansasii isolates revealed 160 subtype I (157 clinical and 3
environmental), 8 subtype II (clinical) and 6 subtype IV (5 clinical and 1 environmental)
strains. Twenty-two isolates (21 clinical and 1 environmental) did not show the typical M.
kansasii PRA patterns. After confirmation by DNA sequencing as belonging to the M.
kansasii species, the results suggested that these isolates were probably new subtypes of M.
kansasii. In contrast to the clonal population structure found amongst the subtype I isolates
from studies in other countries, DNA fingerprinting of 114 subtype I clinical and
environmental isolates showed genetic diversity amongst the isolates. One of the
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environmental isolates showed 100% identity with a clinical isolate, suggesting that water
distribution systems are the possible sources of M. kansasii infection for the miners. An
investigation into the genetic differences between clinical (subtype I) and environmental (III,
IV and V) isolates, using Hybridisation Monitored Differential Analysis (HMDA), identified
45 open reading frames (ORFs) encoding predominantly membrane-associated proteins that
include six potential virulence factors, two family members of transcription regulators for
drug and xenobiotic metabolism, three family members of multidrug efflux systems, a
number of proteins associated with lipid and carbohydrate metabolism and transport, and a
number of hypothetical proteins with unknown function. Immunological analysis of M.
kansasii isolates, using the Lymphocyte Transformation and Cytometric Bead Array assays,
showed that M. kansasii modulates immune responses through suppression of lymphocyte
blastogenesis and by altering the expression of Th1/Th2/Th17 cytokines by human
lymphocytes in vivo for its own survival. This study demonstrated for the first time that water
distribution systems in South Africa are possible sources of M. kansasii infection, and
showed that subtype I strains of M. kansasii from the study region display genetic diversity
and have unique or divergent genes not found in other subtypes. It also demonstrated that
immunosuppression is one of the pathogenic mechanisms employed by M. kansasii.
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Whole genome sequence of Mycobacterium kansasii isolates of the genotype 1 from Brazilian patients with pulmonary disease demonstrates considerable heterogeneity25 June 2018 (has links)
Yes / Mycobacterium kansasii is an opportunistic pathogen and one of the most commonly encountered species in individuals with lung disease. We here report the complete genome sequence of 12 clinical isolates of M. kansasii from patients with pulmonary disease in Brazil. / CNPq (scholarships 207422/2014-1, 500769/2014-1, 311554/2013-0; grants 407624/2012-0, 459100/2014-9).
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A Study of the Predisposition for Mycobacterium Kansasii Infections in Dallas and Tarrant Counties Due to "Influenza-Like" InfectionsGood, Willis E. 05 1900 (has links)
The problem of this study was to review within Dallas and Tarrant Counties the relationship between an "influenza-like" illness within six months prior to contracting Mycobacterium kansasii disease. An interview instrument was developed and used during personal interviews to collect data. Additional data of case rates and reported cases was compiled from local and national governmental public health agencies. Analysis of the data indicated no significant difference between an individual contracting an "influenzalike" illness within six months prior to the acquiring of Mycobacterium kansasii disease. Therefore, there is no relationship between having had influenza-like symptoms within six months of contracting Mycobacteria kansasii.
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Genomic Analysis of Pathogenicity Determinants in Mycobacterium kansasii Type IGuan, Qingtian 05 1900 (has links)
Mycobacteria, a genus within Actinobacteria Phylum, are well known for two pathogens that cause human diseases: leprosy and tuberculosis. Other than the obligate human mycobacteria, there is a group of bacteria that are present in the environment and occasionally cause diseases in immunocompromised persons: the non-tuberculosis mycobacteria (NTM). Mycobacterium kansasii, which was first discovered in the Kansas state, is the main etiologic agent responsible for lung infections caused by NTM and raises attention because of its co-infection with human immunodeficiency virus (HIV).
Five subspecies of M. kansasii (Type I-V) were described and only M. kansasii Type I is pathogenic to humans. M. kansasii is a Gram-positive bacteria that has a unique cell wall and secretion system, which is essential for its pathogenicity. We undertook a comparative genomics and transcriptomic approach to identify components of M. kansasii Type I pathogenicity. Our previous study showed that espA (ESX-1 essential protein) operon, a major component of the secretion system, is exclusively present in M. kansasii Type I. The purpose of this study was to test the functional role of the espA operon in pathogenicity and identify other components that may also be involved in pathogenicity. This study provides a new molecular diagnostic method for M. kansasii Type I infection using PCR (Polymerase Chain Reaction) technique to target the espAoperon. With detailed manual curation of the comparative genomics datasets, we found several genes exclusively present in M. kansasii Type I including ppsA/ppsC and whiB6, that we believe are involved, or have an effect on ESX-mediated secretion system. We have also highlighted, in our study, the differences in genetic components coding for the cell membrane composition between the five subspecies of M. kansasii. These results shed light on genetic components that are responsible for pathogenicity determinants in Type I M. kansasii and may help to design better control measures and rapid diagnostic tools for monitoring these group of pathogens.
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