final tb

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Information about final tb

Published on August 13, 2013

Author: aditya0291


Comic Sans MS: Tuberculosis is a chronic specific inflammatory infectious disease caused by Mycobacterium tuberculosis in humans. During the 17th and 18th centuries, nearly 100% of the European population was infected with  M. tuberculosis . Tuberculosis became known as the White Plague. Dr Robert Koch was the first scientist to describe the pathogen associated with Tuberculosis. Mycobacterium tuberculosis is part of a larger family including  M. bovis, M. africanum  and  M. avium . Multi-drug resistant and now Extensive Drug Resistant TB have emerged. TB can be either active or latent with the host. INTRODUCTION Times New Roman: CHARECTERISTICS OF M. TUBERCULOSIS N onmotile and rod shaped (2-4 µm in L and 0.2-0.5µm in W ). Generation time of  15-20 hour . An obligate aerobe and requires a host for growth and reproduction. Facultative intracellular parasite   Gram-positive and nonspore -forming. Sixty percent of the cell wall is mycolic acids which determine the virulence. Can reproduce with in the phagocytic cells like dendritic cells and marophages . Can remain dormant for decades. Wingdings: PULMONARY TB- 85% of all TB cases EXTRAPULMONARY SITES. SITES INVOLVED RISK FACTORS Low socioeconomic status Crowded living conditions Diseases that weakens immune system like HIV Person on immunosuppresants like steroid Health care workers Migration from a country with a high number of cases Alcoholism Recent Tubercular infection(within last 2 year) Lymph nodes, they will swell. Bones and joints, this is called the Pott disease. Brains, this infection of the brain is rare but most of the time fatal. The urinary tract and reproductive organs. Miliairy tuberculosis, TB enters the bloodstream, this is often fatal Intestine Skin Tw Cen MT: Virulence factors Actions Special mechanisms for cell entry bind directly to mannose receptors on macrophages via the cell wall-associated mannosylated glycolipid, LAM, or indirectly via certain complement receptors or Fc receptors Intracellular growth an effective means of evading the immune system. finding a protected environment for growth in the macrophage Detoxification of oxygen radicals MTB interferes with the toxic effects of reactive oxygen intermediates produced in the process of phagocytosis Antigen 85 complex group of proteins known to bind fibronectin may aid in walling off the bacteria from the immune system and facilitate tubercle formation. Slow generation time immune system may not readily recognize the bacteria or may not be triggered sufficiently to eliminate them High lipid concentration in cell wall accounts for impermeability and resistance to antimicrobial agents, resistance to killing by acidic and alkaline compounds ,resistance to osmotic lysis Cord factor exact role in virulence is unclear, although it has been shown to induce granulomatous reactions identical to those seen in TB VIRULENCE MECHANISMS AND VIRULENCE FACTORS Office Theme: 19-kDa protein The 19-kDa M.tuberculosis glycolipoprotein (p19) is both cell wall-associated and secreted and is a candidate virulence factor. p19 actS to induce apoptosis in differentiated THP-1 cells and monocyte -derived macrophages. Glutamine synthase i ) Synthesis of L-glutamine, a major component of the cell wall of pathogenic mycobacteria , and (ii) the modulation of the ammonia level in the M. tuberculosis phagosome , which may in turn influence phagosomal pH and phagosomelysosome fusion. oxidative stress proteins These are enzymes produced by the bacteria to combat oxygen radicals which are normal by-products of aerobic respiration and are also produced by the phagocytic respiratory burst. Nitrate reductase If anaerobic or microareophilic growth is an important feature of  M. tuberculosis  physiology during infection, the existence of nitrate reductase could be a significant factor in sustaining growth under these conditions. PowerPoint Presentation: adherence The bacterium produces  pili  during human infection, which could be involved in initial colonization of the host .These form a dense fibrillar meshwork composed of thin coiled, aggregated fibers resembling pili that extend many microns away from the bacterial surface. These structures have been named  Mycobacterium tuberculosis   pili or  MTP . PowerPoint Presentation: Common symptoms of pulmonary tuberculosis are- Productive cough 3 weeks or longer Shortness of breath, Chest pain, Hemoptysis fever/Night sweats, Unexplained weightloss, Fatigue CLINICAL FEATURES HOW IS TB TRANSMITTED? Person-to-person through the air by a person with active TB disease of the lungs. Less frequently transmitted by: Ingestion of Mycobacterium bovis found in unpasteurized milk products or auto ingestion. Inoculation (in skin tuberculosis). Transplacental route (rare route) PowerPoint Presentation: World map showing reported cases of tuberculosis per 100,000 citizens. Red = >300, orange = 200-300; yellow = 100-200; green 50-100; blue = <50 and grey = n/a. EPIDEMIOLOGY It is estimated that approximately 1/3 of the humanity (2 billion people) are infected with TB (WHO 2008) In 2008 highest incidence was in Southeast Asia 98% of TB related deaths occur in developing countries PowerPoint Presentation: PORTAL OF ENTRY The mode of infection is by direct inhalation of aerosolised bacilli contained in the droplet nuclei of expectorated sputum. Coughing, sneezing and speaking release numerous droplets (as many as 3000 infectious nuclei per cough). Infection also occurs infrequently by ingestion, for example, through infected milk. Rarely by inoculation PowerPoint Presentation: Majority of the inhaled bacilli are arrested by the natural defenses of the upper respiratory tract. Bacilli reaching the lungs are ingested by the alveolar macrophages. Several factors influence the outcome of the infection - the number and virulence of the infecting bacilli host factors including genetic susceptibility, immuno -competence, nutrition and coexisting illness PowerPoint Presentation: Pathogenesis PowerPoint Presentation: Lungs infected with tuberculosis PORTAL OF ENTRY: Condition of patients PowerPoint Presentation: 1) Sputum examination- Smear should be prepared from thick dirty part of sputum & stained with ZIEHL-NEELSON Auramine shodamine 2) Culture- Culture is done in Lowenstein Jansen media. Diagnosis PowerPoint Presentation: Arrow points to cavity in patient's right upper lobe 4) Chest x-ray- 3) TUBERCULIN (MONTOUX )TEST- 5 IU PPD is extensor aspect of forearm tuberculin. size of induration is measured 48–72 hours later. PowerPoint Presentation: Recent Methods for Diagnosis BACTEC 460 ( rapid radiometric culture system Mycobacteria Growth Indicator Tube (MGIT ) Polymerase Chain Reaction (PCR) & Gene probe FASTplaque TB Test Interferon – γ Tests PowerPoint Presentation:  Always treat with multiple drugs. Never add a single drug to a failing regimen. DOTS (Directly Observed Treatment Short course) is given. Treatment course depends on the categories of the patient. Usually 6 months, sometimes 9 months. Four drugs for two months. Isoniazid – Rifampicin – Ethambutol - Pyrazinamide Two drugs for four or seven months. Isoniazid - Rifampicin Treatment PowerPoint Presentation: Drug resistant tuberculosis Reasons – These drugs are misused or mismanaged. Patients do not complete their full course of treatment Health-care providers prescribe the wrong treatment, The wrong dose Length of time for taking the drugs The supply of drugs is not always available The drugs are of poor quality . Multidrug-resistant tuberculosis (MDR TB)   Resistant to at least two of the best anti-TB drugs, isoniazid and rifampicin which are first-line drugs used to treat all persons with TB disease.  Extensively drug resistant TB (XDR TB)   Resistant to isoniazid and rifampin, plus to any fluoroquinolone and one of three injectable 2nd-line drugs (i.e., amikacin, kanamycin, or capreomycin). As resistant to 1st-line and 2nd-line drugs

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