Tuberculosis

TuberculosisMaxs U.E. Sanam

Tuberculosis (TB) adalah penyakit granulamatosa menular, disebabkan oleh kuman genus Mycobacterium, berbentuk batang, Gram-positif, dan bersifat tahan asam

Penyakit umumnya berlangsung secara kronis, dan sangat melemahkan (debilitating)EtiologiTipe-tipe utama dari Mycobacterium tuberculosis complex (basil tuberkel mamalia) yang dikenal adalah:M tuberculosisM bovisM capraeM pinnipediiM microti, danM africanumMycobacterium TuberculosisGeneral Characteristics - Family Mycobacteriaceae - Gram-positive aerobic rod-shaped bacilliAcid fast bacteriaLack of spore formation and toxin productionNo capsule, flagellum (non-motile)Generation time of 18- 24 hours but requires 3-4 weeks for visual colonies

Pathological FeaturesPrinciple cause of Human TuberculosisIntracellular pathogen (alveolar macrophages)Waxy, thick, complex cellular envelope Cell envelope components ex) sulfolipids Produces tubercles, localized lesions of M. tuberculosis

SEM of M. tuberculosisM. Tuberculosis (stained in purple)Mycobacterial Cellular EnvelopeMain ComponentsPeptidoglycan contains N-glycolylmuramic acid instead of N-acetylmuramic acidArabinogalactanMycolic Acids (60% of cellular envelope)Lipoarabinomannan (LAM)

Mycobacterial Cellular Envelope

Contribution of Mycobacterial Cellular Envelope to PathogenesisResistance to Drying and Other Environmental FactorsThick, waxy nature of cellular envelope protects M. tuberculosis from drying, alkali conditions, and chemical disinfectantsHinders entrance of antimicrobial agents

Entry into Host Cells Lipoarabinomannan (LAM) binds to mannose receptors on alveolar macrophages leading to entry into the cell

Interference of Host Immune Response- Glycolipids and sulfolipids decrease the effects of oxidative cytotoxic mechanismInhibition of phagosome and lysosome fusion inside macrophageWaxy cellular envelope prevents acidification of the bacteria inside the phagosomeFactors Affecting PathogenicityActive InfectionOnly individuals with an active infection can transmit the disease

TransmissionAerosolized droplets need to be