Mycobacteria Flashcards
General Characteristics of Mycobacteria
- Acid-fast
- Thick cell wall, lipids
- Hydrophobic and resistant to disinfectants
- Slow growers
Slow Growing Pathogenic Species
3
- M. tuberculosis
- M. marinum
- M. ulcerans
Slow Growing Opportunistic Species
2
- M. avium complex
- M. kansasii
Rapid Growing Opportunistic Species
3
- Mycobacteroides abscessus
- Mycobacteroides chelonae
two above are part of a complex - M. fortuitum
Mycobacterium Tuberculosis: Basics
where, trans, clinical
Habitat: humans natural, 1/3 of world
Transmission: close person to person contact with aerosols, congenital rare
Clinical: primary and secondary tuberculosis
Mycobacterium Tuberculosis: Tuberculosis Infection Basics
1 vs 2
Primary: self limiting, most cases, infection without any prior exposure, mild - becomes latent TB
Secondary: years or decades later after initial infection
Mycobacterium Tuberculosis: Pathogenesis
Encounter/entry: airborne, droplet, remain in air, good size to bypass mucous blanket
Spread
- Primary/dormant: multiply in macrophages, immune system curbs proliferation, macrophages kill microbes = tubercules (granulomas with cells) - mild or asymptomatic
- Secondary/disease: chronic, compromise cellular immunity, lung lesions and necrotic, inflammation - bloody sputum
Mycobacterium Tuberculosis: TB Disease/Active TB
- Weakening of immune system
- Bacteria attack body and destroy tissue
- Can develop before immune system can fight off bacteria
- Shows cavitary lesion of lung in x-ray
Mycobacterium Leprae: Basics
where, trans, clinical
Habitat: humans and armadillos in southern USA
Transmission: droplets, Brazil, India, Indonesia
Clinical: Leprosy, males more affected
Mycobacterium Leprae: Leprosy
Where: skin, nerves, mucous membranes
Incubation: 2-10 years
Symptoms
- Skin lesions, ulcers
- Pain and numbness
- Weakness of paralysis
- Eye problems
Most people naturally immune
Mycobacterium Ulcerans: Basics
where, trans, clinical
Habitat: contaminated stagnant/slow water, not understood
Transmission: skin trauma
Clinical: buruli ulcer, third most common mycobacterial infection after TB and leprosy
Mycobacterium Ulcerans: Infection
Buruli ulcer
- Painless nodule at first
- Breaks down, forms ulcer, sometimes spontaneous healing over months
- Progress into joints and bones, amputation
Mycobacterium Marinum: Basics
where, trans, clinical
Habitat: fresh and salt water, marine organisms
Transmission: skin exposure to water
Clinical: skin infection
- Fish tank granuloma, sometimes positive TB skin test
Mycobacterium Avium Complex: Basics
species, where, trans, clinical
Species: M. avium, M. intracellulare
Habitat: environment, soil, water, dust
Transmission: ingestion of contam. stuff, inhaling, zoonotic poultry and swine
Clinical: chronic pulmonary, disseminated in AIDS patients (most common in AIDS)
Mycobacterium Kansasii: Basics
where, trans, clinical
Habitat: water, tap water
Transmission: aerosol route
Clinical: chronic pulmonary, resembles TB, COPD patients risk
