Bacterial Typing Techniques ; Mycobacterium tuberculosis ; classification ; genetics ; pathogenicity

BACKGROUNDMycobacterial interspersed repetitive units-variable number tandem repeat (MIRU-VNTR) and Beijing family typing based on detecting the deletion of RD105 sequence are two common genotyping methods used to study the molecular epidemiologic characteristics of Mycobacterium (M.) tuberculosis. We collected 218 strains of M. tuberculosis between 2004 and 2006 in the Linxia Hui Autonomous Prefecture of Gansu province in Northwest China.

METHODSMIRU-VNTR analysis and Beijing family typing based on detecting the deletion of RD105 sequence were used to type the 218 strains, and their typing power was evaluated to look for practical and efficient genotyping methods suitable for the region.

RESULTSThe MIRU typing yielded 115 distinct genotypes, including 98 unique isolates and 17 different clusters containing 120 isolates (55.05%); the cluster rate was 47.25%. By detecting the deletion of RD105 sequence, 188 of 218 (86.23%) isolates belonged to Beijing family. Combination of Beijing family typing and MIRU typing yielded 118 distinct patterns, including 101 unique isolates and 17 clusters containing 117 isolates (54.13%). The largest cluster contained 58 strains with MIRU genotype of 223325173533 which contained 50 strains belonging to Beijing family and 8 strains belonging to non-Beijing family.

CONCLUSIONSThe Beijing family strains occupied a large proportion and the Beijing family MIRU genotype 223325173533 is a dominant strain in Linxia of Gansu. Combining detecting the deletion of RD105 and MIRU typing together provides a simple, fast, and effective method which is low in cost and might be practical and suitable for M. tuberculosis genotyping in China.

Alleles ; China ; epidemiology ; Genotype ; Molecular Epidemiology ; Multiplex Polymerase Chain Reaction ; Mycobacterium tuberculosis ; genetics ; pathogenicity ; Tuberculosis ; epidemiology

OBJECTIVEThis study aimed to review the available literatures on control of latent tuberculosis (TB) infection and propose a new control strategy to shorten the course of TB chemotherapy.

DATA SOURCESThe data used in this review were mainly obtained from articles listed in PubMed. The search terms were "therapy (treatment) of tuberculosis," "therapy (treatment) of latent TB infection," and "vaccine of TB."

STUDY SELECTIONArticles regarding treatment and vaccine of TB were selected and reviewed.

RESULTSThe most crucial reason causing the prolonged course of TB chemotherapy is the dormant state of Mycobacterium tuberculosis (M. tuberculosis). Nevertheless, there are, to date, no effective drugs that can directly kill the dormant cells of M. tuberculosis in clinical therapy. In accordance with the growth cycle of dormant M. tuberculosis in the body, the methods for controlling dormant M. tuberculosis include direct killing with drugs, prevention of dormant M. tuberculosis resuscitation with vaccines, and resuscitating dormant M. tuberculosis with preparations or drugs and then thoroughly killing these resuscitated M. tuberculosis by using anti-TB therapy.

CONCLUSIONSThe comprehensive analysis of the above three methods suggests that the drugs directly killing dormant cells are in clinical trials, TMC207 is the most beneficial for controlling TB. Because the side effect of vaccines is less and their action period is long, prevention of dormant cells resuscitation with vaccines is promising. The last control method makes it probable that when a huge number of active cells of M. tuberculosis have been killed and eradicated after 1-month short chemotherapy, only a strong short-term subsequent chemotherapy can completely kill and eradicate the remaining M. tuberculosis. This control strategy is expected to significantly shorten the course of TB chemotherapy and bring a new change and breakthrough in TB treatment.

Antitubercular Agents ; therapeutic use ; Diarylquinolines ; therapeutic use ; Humans ; Latent Tuberculosis ; drug therapy ; Mycobacterium tuberculosis ; pathogenicity ; Tuberculosis ; drug therapy

OBJECTIVETo explore the influences of Mycobacterium tuberculosis on the levels of human acute monocytic leukemia cell line THP-1 apoptosis and death.

METHODSHuman acute monocytic leukemia cell line THP-1 were infected with Mycobacterium tuberculosis strains H37Ra, H37Rv, or Beijing genotype (BJTB), respectively, to construct the infection models. Cell apoptosis was detected using flow cytometry. The distribution of the apoptotic proteins was detected using immunofluorescent staining assays. The cells late apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining assays. The change of cell death was determined by Tyrpan blue staining assays.

RESULTSTHP-1 apoptosis was induced by Mycobacterium tuberculosis strains H37Ra, H37Rv, and BJTB. H37Ra strongly induced THP-1 apoptosis, H37Rv weakly induced THP-1 apoptosis, and BJTB induced THP-1 apoptosis at the lowest level among these three Mycobacterium tuberculosis strains. On the contrary, BJTB strongly induced THP-1 death, H37Rv weakly induced THP-1 death, and H37Ra induced THP-1 death at the lowest level.

CONCLUSIONSMycobacterial strains with different virulence induce different levels of apoptosis and death of THP-1 cells. Compared with highly virulent strains, attenuated strains induce more apoptosis and less death.

Apoptosis ; Cell Line, Tumor ; Humans ; In Situ Nick-End Labeling ; Leukemia, Monocytic, Acute ; Mycobacterium tuberculosis ; pathogenicity ; Virulence

Expression microarray was employed in this study to investigate whether the ion channels and their regulatory elements encoding genes participate in the immune response to Mycobacterium tuberculosis infection. The results of a virulent strain were compared with those of the clinically isolated strains. The data demonstrate that K(+), Na(+), Ca(2+) and Cl(-) channels and their regulatory elements, such as the G protein, receptor and second messenger, protein kinase and protein phosphatase were involved in the immune reaction. The clinical strain affected more types of ion channels and respective regulatory elements. The data provides clues for further scrutiny into the role of ion channels and related elements in the interaction between Mycobacterium tuberculosis and host macrophage.
Gene Expression Regulation ; Humans ; Ion Channels ; genetics ; Macrophages ; immunology ; microbiology ; Mycobacterium tuberculosis ; pathogenicity ; Regulatory Elements, Transcriptional ; Tuberculosis ; genetics ; immunology ; microbiology

Tuberculosis ranks as the second deadly infectious disease worldwide. The incidence of tuberculosis is high in China. Refractory wound caused by Mycobacterium tuberculosis infection ranks high in misdiagnosis, and it is accompanied by a protracted course, and its pathogenic mechanism is still not so clear. In order to study its pathogenic mechanism, it is necessary to reproduce an appropriate animal model. Up to now the study of the refractory wound caused by Mycobacterium tuberculosis infection is just beginning, and there is still no unimpeachable model for study. This review describes two models which may reproduce a wound similar to the wound caused by Mycobacterium tuberculosis infection, so that they could be used to study the pathogenesis and characteristics of a tuberculosis wound in an animal.
Animals ; Disease Models, Animal ; Mycobacterium tuberculosis ; isolation & purification ; pathogenicity ; Surgical Wound Infection ; diagnosis ; microbiology ; Tuberculosis ; complications ; diagnosis ; microbiology

Along with the rapid spread of HIV / AIDS and TB prevalence, prevention and control of AIDS and tuberculosis has become an urgent problem in the field of public health. Recent studies demonstrate dual infections of HIV and TB are not a simple superposition of two diseases, but a course of mutual promotion. This article has summarized the pathological mechanisms and mutual interactions of HIV/TB dual infections.
Acquired Immunodeficiency Syndrome ; complications ; epidemiology ; prevention & control ; Coinfection ; HIV-1 ; pathogenicity ; Humans ; Mycobacterium tuberculosis ; pathogenicity ; Prevalence ; Public Health ; Tuberculosis ; complications ; epidemiology ; prevention & control

BACKGROUNDGene chip array can differentiate isolated mycobacterial strains using various mycobacterium specific probes simultaneously. Gene chip array can evaluate drug resistance to isoniazid and rifampin of tuberculosis strains by detecting drug resistance related gene mutation. This technique has great potential for clinical application. We performed a retrospective study to investigate the capability of gene chip array in the rapid differentiation of species and detection of drug resistance in mycobacterium, and to evaluate its clinical efficacy.

METHODSWe selected 39 patients (54 clinical mycobacterium isolates), used gene chip array to identify the species of these isolates and detect drug resistance to isoniazid and rifampin in Mycobacterium tuberculosis isolates. Meanwhile, these patients' clinical data were analyzed retrospectively.

RESULTSAmong these 39 patients whose mycobacterium culture were positive, 32 patients' isolates were identified as Mycobacterium tuberculosis, all of them were clinical infection. Seven patients' isolates were identified as non-tuberculosis mycobacterium. Analyzed with their clinical data, only two patients were considered as clinical infection, both of them were diagnosed as hematogenous disseminated Mycobacterium introcellulare infection. The other five patients' isolates were of no clinical significance; their clinical samples were all respiratory specimens. Clinical manifestations of tuberculosis and non-tuberculous mycobacterial infections were similar. Isoniazid resistance was detected in two tuberculosis patients, while rifampin resistance was detected in one tuberculosis patient; there was another patient whose Mycobacterium tuberculosis isolate was resistant to both isoniazid and rifampin (belongs to multidrug resistance tuberculosis). The fact that this patient did not respond to routine anti-tuberculosis chemotherapy also confirmed this result.

CONCLUSIONSGene chip array may be a simple, rapid, and reliable method for the identification of most mycobacterial species and detection of drug resistance in Mycobacterium tuberculosis. It is useful in diagnosis, treatment, and hospital infection control of mycobacterial infections, and it may have a great potential for clinical application.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antitubercular Agents ; therapeutic use ; Female ; Humans ; Isoniazid ; therapeutic use ; Male ; Middle Aged ; Mycobacterium ; classification ; genetics ; pathogenicity ; Mycobacterium tuberculosis ; genetics ; pathogenicity ; Oligonucleotide Array Sequence Analysis ; methods ; Rifampin ; therapeutic use ; Tuberculosis, Multidrug-Resistant ; genetics ; Young Adult

OBJECTIVETo clone and express the Rv3871 gene related to the virulent protein secretion of Mycobacterium tuberculosis and analyze its molecular structure, function and homology using bioinformatic approach.

METHODSA pair of primers was designed to amplify the Rv3871 gene, which was subcloned into the prokaryotic plasmid pET32a(+). The recombinant plasmid was identified by sequence analysis and the expressed recombinant protein by SDS-PAGE. The structure, function and homology alignment of Rv3871 were analyzed comparatively against other mycobacteria.

RESULTSThe restriction fragments through molecular cloning matched perfectly in size with our prediction. The gene sequence was consistent with the corresponding sequence in GenBank. The expression protein was detected by SDS-PAGE with a molecular weight of 84 kD. Two FtsK/SpoE III domains were found by bioinformatic analysis. The homology results showed distinct differences between Rv3871 of the pathogenic M. tuberculosis and its counterparts in non-pathogenic mycobacteria.

CONCLUSIONMolecular cloning, expression and sequencing identify the structural and functional characteristics of Rv3871. The structural and functional differences of the gene between pathogenic and non-pathogenic mycobacteria identified by bioinformatics provide some evidence for the pathogenesis and drug targets of tuberculosis.

Bacterial Proteins ; genetics ; metabolism ; Cloning, Molecular ; Computational Biology ; Mycobacterium tuberculosis ; genetics ; metabolism ; pathogenicity ; Recombinant Proteins ; genetics ; metabolism ; Virulence ; genetics

BACKGROUNDT-SPOT.TB is a novel test for tuberculosis infection with higher sensitivity and specificity than the traditional tuberculin skin test (TST). However, there are no longitudinal data in the literature evaluating T-SPOT.TB for Mycobacterium tuberculosis in patients with acquired immune deficiency syndrome (AIDS) on highly active antiretroviral therapy (HAART). The objective of this study was to assess the value of T-SPOT.TB longitudinally in AIDS patients on HAART without prophylaxis for tuberculosis.

METHODSA prospective observational study was conducted in 50 AIDS patients on HAART. None of the subjects had evidence of active tuberculosis. T-SPOT.TB, a T-cell-based interferon gamma released assay, was performed at the onset of the study and repeated 24 months thereafter. Subjects were evaluated every 6 months during the 36-month follow-up.

RESULTSTwenty-one (42%) AIDS patients on HAART tested positive by T-SPOT.TB (95%CI 28.3% - 55.7%). The pooled spot-forming cells of early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) peptides were 68/million peripheral blood mononuclear cell (PBMC) (interquartile range 44 - 220). The average number of CD4 cells in subjects was (305 +/- 152) cells/microl, and there was no significant difference in T-SPOT.TB response rates between subjects with CD4 cell counts < 200 cells/microl (7/15 (46.7%), 95%CI 21.5% - 71.9%) and those with CD4 cell counts >/= 200 cells/microl (14/35 (40.0%), 95%CI 23.8% - 56.2%, P = 0.662). In the 32 subjects who completed the 24-month follow-up, 10 underwent T-SPOT.TB reversion, one had T-SPOT.TB conversion, six remained positive and 15 remained negative. None of them advanced to active tuberculosis during the 36-month follow-up.

CONCLUSIONThe inactive status of tuberculosis infection may be maintained for a long period in AIDS patients on HAART.

Acquired Immunodeficiency Syndrome ; drug therapy ; immunology ; microbiology ; Adult ; Antiretroviral Therapy, Highly Active ; Female ; Humans ; Interferon-gamma ; secretion ; Male ; Middle Aged ; Mycobacterium tuberculosis ; pathogenicity ; Prospective Studies ; Tuberculosis ; diagnosis ; immunology