Mycobacteria Flashcards
General growth rate of Mycobacteria
Slow
16-18 hours for one division
Why is Mycobacteria Acid Fast?
Large amounts of lipids in cell wall
Aerobic/Anaerobic?
Motile/NonMotile?
Spore forming/nonspore forming?
Aerobic
Non motile
Non spore forming
Shape of Mycobacteria
Rod shaped
Beaded
Virulence mechanisms of Mycobacteria?
Intracellular survival resisting phagocytic acidification
Bodily defenses against Mycobacteria?
Delayed type hypersensitivity
Acquired cellular immunity
TB most often route of entry?
Respiratory
Mode of infection for TB
Alveolar macrophages eat TB, T-Cells arrive 4-6 weeks later, bacteria eliminated –> primary lesion heals or hard tubercle/granulomar forms if bacteria not eliminated
Who develops miliary TB?
Young kinds, immunosuppressed, old people
Factors contributing to reactivation of TB
Malnutrition
Alcoholism
Homelessness
Immunosuppressed
AIDS
Incarceration
Pathology of Tuberculosis
Tubercle or Caseation
Tubercle - Physical walling off of TB
Caseation - Cheese-like necrotic tissue from the original alveolar lesion
Other sites for TB
Cervical lymphadenitis
Pleuritis
Pericarditis
Synovitis
Meningitis
Skin
Miliary tuberculosis (disseminated)
Spine
Lab features of TB
Slow growing
Non-pigmented, rough
Serpentine cording in liquid media
Key lab test results for TB
Niacin pos
Nitrate pos
68C Catalase neg
Hansen’s Disease AKA
Leprosy
How is Leprosy transferred?
From the nose
Incubation period of M. leprae
Years
Symptoms of Leprosy
Anesthetic skin lesions
Peripheral neuropathy
Nerve thickening
Deformation
How is Leprosy diagnosed?
Clinical symptoms, acid fast, armadillos
What does M. leprae grow on?
Cannot grow on artificial media
Tuberculoid Leprosy
More localized,
More serious
Not very infection
Lepromatous Leprosy
Disseminated
More infectious
How is Leprosy treated?
Curable with antibiotics
Non-infectious after 3 days
Treatable with thalinomide
Slow growing bacteria other than TB
Avium
kansasii
marinum
szulgai
scrofulaceum
ulcerans
Most commonly isolated Mycobacteria sp.?
M. avium
Pathogenicity of avium
Low, except AIDS/immunosuppressed
Diseases M. avian causes
TB-like pulmonary disease
Cervical lymphadenitis
Disseminated
Chrons Disease (M. avium paratuberculosis)
Colony lab features of M. avium
Slow-growing
Non-pigmented
Heterogenous morphology
Biochemical reactions M. avium
HS Catalase pos
T2H pos
Tellurite pos
Pyrazinamidase