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Association of Mycobacterium Tuberculosis Lineages with IFN-γ and TNF-α Gene Polymorphisms among Pulmonary Tuberculosis Patient

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      Abstract

      The six major lineages of Mycobacterium tuberculosis [MTB] are found to be strongly associated with specific geographical outbreaks. But whether these bacterial lineages influence the host genetic polymorphism is uncertain. The present study was designed to evaluate the relevance of strain diversity and host genetic polymorphisms in susceptibility to pulmonary tuberculosis [PTB]. For this reason, single –nucleotide polymorphisms [SNPs] in interferon- γ [IFN-γ] receptor-1[G-611A], IFNG [G+ 2109A] and tumor necrosis factors [TNF-α] genes [at −238, 308,−857position] in patients [n=151] were analyzed and compared with controls [n=83]. The genetic diversity of M. tuberculosis isolates was performed using spacer oligonucleotide typing. Thereafter, the profile of IFN-γ and TNF-α allele frequency were investigated in each subtype of M.tuberculosis. The results showed C allele of TNF 857 and A allele of TNF 238 were more frequent in PTB cases [[TNF 857 C allele OR [CI95%] 0.6[0.4–0.9], p= 0.02] for TNF 238 A allele OR [CI95%] 5.5[3.4–9.0], p= 0.00]]. Similarly, G allele in IFNG+ 2109 A/G polymorphism were significantly more in patients than control subject[OR[CI95%] 0.3; p< 0.05]. The major identified clinical isolates of M. tuberculosis were EAI[42; 27.8% ], Haarlem[ 31; 20.5% ], CAS [ 23;15.2% ], Beijing[14; 9.2%], and T [11; 7.2% ] lineages. No correction was observed between strains diversity and frequency of SNPs in studied PTB cases. In conclusions, we exclude the possibility of genetic mutation in IFN-γ and TNF-α gene by different subtypes of M. tuberculosis. Although, our results supports a positive correlation between host SNPs and susceptibility to PTB.

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      Simultaneous detection and strain differentiation of Mycobacterium tuberculosis for diagnosis and epidemiology.

      Widespread use of DNA restriction fragment length polymorphism (RFLP) to differentiate strains of Mycobacterium tuberculosis to monitor the transmission of tuberculosis has been hampered by the need to culture this slow-growing organism and by the level of technical sophistication needed for RFLP typing. We have developed a simple method which allows simultaneous detection and typing of M. tuberculosis in clinical specimens and reduces the time between suspicion of the disease and typing from 1 or several months to 1 or 3 days. The method is based on polymorphism of the chromosomal DR locus, which contains a variable number of short direct repeats interspersed with nonrepetitive spacers. The method is referred to as spacer oligotyping or "spoligotyping" because it is based on strain-dependent hybridization patterns of in vitro-amplified DNA with multiple spacer oligonucleotides. Most of the clinical isolates tested showed unique hybridization patterns, whereas outbreak strains shared the same spoligotype. The types obtained from direct examination of clinical samples were identical to those obtained by using DNA from cultured M. tuberculosis. This novel preliminary study shows that the novel method may be a useful tool for rapid disclosure of linked outbreak cases in a community, in hospitals, or in other institutions and for monitoring of transmission of multidrug-resistant M. tuberculosis. Unexpectedly, spoligotyping was found to differentiate M. bovis from M. tuberculosis, a distinction which is often difficult to make by traditional methods.
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        Worldwide Occurrence of Beijing/W Strains of Mycobacterium tuberculosis: A Systematic Review

        Strains of the Beijing/W genotype family of Mycobacterium tuberculosis have caused large outbreaks of tuberculosis, sometimes involving multidrug resistance. This genetically highly conserved family of M. tuberculosis strains predominates in some geographic areas. We have conducted a systematic review of the published reports on these strains to determine their worldwide distribution, spread, and association with drug resistance. Sixteen studies reported prevalence of Beijing strains defined by spoligotyping; another 10 used other definitions. Beijing strains were most prevalent in Asia but were found worldwide. Associations with drug resistance varied: in New York, Cuba, Estonia, and Vietnam, Beijing strains were strongly associated with drug resistance, but elsewhere the association was weak or absent. Although few reports have measured trends in prevalence, the ubiquity of the Beijing strains and their frequent association with outbreaks and drug resistance underline their importance.
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          A marked difference in pathogenesis and immune response induced by different Mycobacterium tuberculosis genotypes.

          In the last decade, an unprecedented genetic diversity has been disclosed among Mycobacterium tuberculosis strains found worldwide. However, well-conserved genotypes seem to prevail in areas with high incidence of tuberculosis. As this may be related to selective advantages, such as advanced mechanisms to circumvent [M. bovis Bacille Calmette-Guerin (BCG)-induced] host defence mechanisms, we investigated the influence of strain diversity on the course of experimental disease. Twelve M. tuberculosis strains, representing four major genotype families found worldwide today, and the laboratory strain H37Rv were each used to infect BALB/c mice by direct intratracheal injection. Compared with H37Rv, infections with Beijng strains were characterized by extensive pneumonia, early but ephemeral tumour necrosis factor-alpha (TNF-alpha) and inducible isoform of nitric oxide synthetase (iNOS) expression, and significantly higher earlier mortality. Conversely, Canetti strains induced limited pneumonia, sustained TNF-alpha and iNOS expression in lungs, and almost 100% survival. Strains of the Somali and the Haarlem genotype families displayed less homogeneous, intermediate rates of survival. Previous BCG vaccination protected less effectively against infection with Beijing strains than against the H37Rv strain. In conclusion, genetically different M. tuberculosis strains evoked markedly different immunopathological events. Bacteria with the Beijing genotype, highly prevalent in Asia and the former USSR, elicited a non-protective immune response in mice and were the most virulent. Future immunological research, particularly on candidate vaccines, should include a broad spectrum of M. tuberculosis genotypes rather than a few laboratory strains.
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            Author and article information

            Affiliations
            Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease [NRITLD], Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences
            Author notes
            Correspondence to: Parissa Farnia, Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease [NRITLD], Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran,19556, P.O: 19575/154, Iran. E-mail: pfarnia@ 123456sbmu.ac.ir
            Journal
            Mediterr J Hematol Infect Dis
            Mediterr J Hematol Infect Dis
            Mediterranean Journal of Hematology and Infectious Diseases
            Mediterranean Journal of Hematology and Infectious Diseases
            Università Cattolica del Sacro Cuore
            2035-3006
            2014
            16 February 2014
            : 6
            : 1
            3965727 10.4084/MJHID.2014.015 mjhid-6-1-e2014015

            This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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            Original Article

            Infectious disease & Microbiology

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