Microbiology 17 - Mycobacterial disease Flashcards
How are mycobacteria classified?
Based on speed of growth
<7 days = fast
>7 days = slow
Recall 2 examples of slow-growing mycobacteria
M bovis
M tuberculosis
What is the key cell wall component of mycobacteria that makes them so different from other bacteria?
Long chain fatty (mycolic) acids
Recall 2 stains that can be used to identify mycobacteria
Auramine
Ziehl Neelsen
In which patient group is M. avium complex most common?
HIV positive
Which type of mycobacterium is associated with cardiothoracic procedures?
M. chimera
Which mycobactrium species is known as the “swimming poool granuloma”?
M. marinum
How can M. marinum infection present?
Skin lesions on hands and arms of fish-owners
What is the main symptoms of M. ulcerans infection?
Painless, destructive ulcer
What type of infection do fast-growing mycobacteria tend to cause?
Skin and soft tissue infections
How should rapid-growing mycobacteria be treated?
Macrolide + additional antibiotics based on susceptibility testing
What is the most severe form of disease that mycobacterium leprae can cause?
Causes leprosy, aka Hansen’s disease of which there are 3 main subtypes, the worst subtype being the answer to this question
Multibacillary disease aka lepromatous disease
Recall some strategies for TB prevention
Contact tracing and treatment of index case
Screening of those considered at risk
Vaccination
Improvement of living conditions
What is required for diagnosis of TB?
3 sputum samples - smear them and culture them, If they cannot produce sputum, do a bronchoscopy
NAAT (nucelic acid amplification test)- also used to test for chlamydia, gonnorhea, covid) if possible
Can also do a TB EMU (Early morning urine) test if you suspect renal or milliary TB
What are the 2 possible tests for latent TB?
Mantoux test
IGRAS (detection of antigen-specific interferon gamma)
