Mycobacteria Flashcards
Mycobacterium characteristics
Aerobic bacilli - non spore forming -non motile Cell wall - rich in lipids Acid-fast bacilli very slow growing
Mycobacterium tuberculosis pathogenesis
Inhaled aerosols –> engulfed by alveolar macrophages
Bacilli replicate
Macrophages die
Infected macrophages —-> local lymph nodes
Develop Ghon’s focus —> primary complex
Cell mediated immune response –> stops cycle of destruction & spread
Viable but non replicating bacilli present in macrophages
TB presentation
Primary complex asymptomatic can heal or reactivate (post primary TB)
Acute pulmonary disease can lead to systemic spread and can be Asymptomatic (causing later disease Renal/CNS etc) or symptomatic (known as miliary TB)
TB Diagnosis
Chest x ray - hilar lymphadenoptahy
delayed hypersensitive response to PPD
Sputum for AFB
TB treatment
INAH
Rifampicin
Ethambutanol
Pyrazinamide
TB prevention
better housing/nutrition
Case detection & treatment
Contact tracing
Immunization with BCG
Mycobacterium leprae
Acid fast bacilli
Strict human pathogens
only cultivated in vitro
Airborne transmission
Low infectivity
Clinical presentation is dependant on host-parasite interactions:
tuberculoid Borderline tuberculoid Borderline lepromatous Lepromatous
M Kansasii
Respiratory infection
presents similar to TB
Treatment - resistant to anti TB drugs
M Scrofulaceum
Infects cervical lymph nodes
Presets as cervical lymphadenopathy
treatment - surgery
M avium intracellulare
Immuno competant host: Infects cervical lymph nodes Presets as cervical lymphadenopathy treatment - surgery Immuno deficient host: Severe respiratory tract infection severe GI infection septicaemia
M Ulcerans
Burndi ulcer
Prolonged incubation required for growth
M fortuitum / M Chelonei
injection related abscesses
Associated with sternal wound infections following cardio-thoracic surgery
M Marinarum
Swimming pool granulomas
fish tank granuloma
Fish Fancier’s finger
primary pathogen of many fresh and salt water fish
