Lecture 16: Mycobacteria Flashcards
Mycobacteria are obligate ___
Aerobes
What are the shape of mycobacteria
Bacilli
What bacteria is this
mycobacteria
What type of bacteria are myobacteria
Acid fast
What structure of mycobacteria resist detergents and antibiotics
Mycolic acids and lipids in the cell wall
Mycobacteria are heat sensitive killed by pasteurization at __ degrees for ___secs
68.2 degrees C for 30 secs
How long does it take for pathogenic strains of mycobacteria to grow
3-6 weeks
What device can be used to speed up the growth of mycobacteria to ~15 days
BD BACTEC
What stain is used to differentiate mycobacteria from other bacteria
Ziehl-Neelsen stain
what is route of infection for mycobacteria
Inhalation or ingestion
What is the causative agent of Bovine tuberculosis
Mycobacterium bovis
Bovine tuberculosis is difficult to control d/t ___ reservoirs
Wildlife
T or F: bovine tuberculosis is zoonotic
True
How is bovine tuberculosis /M. Bovis transmitted among cattle
Aerosols or calves ingesting contaminated milk
What are the wild reservoirs for Bovine tuberculosis/ M. Bovis
Badgers, deer, elk, feral pigs
What is the pathogens is of Bovine TB/ M. Bovis
- Bacteria taken up by alveolar macrophages and dendritic cells
2a. Dendritic cells—> migrate to LN—> lymphatic TB
2b. M. Bovis survive in macrophages and prevent phagosome-lysosome fusion - Infected macrophages secrete cytokines
- Recruit lymphocytes- granulomatous forms
- Collagen delineates the peripheral, bacteria are contained
Granuloma structure is defined mainly by what cells
Macrophages, T cells, and fibroblasts
Activated macrophages in bovine TB granuloma release __enzymes and result in what
Lytic enzymes that result in necrotic core with caseous (cheese-like) consistently
Granulomas in TB are called ___
Tubercles
What are the virulence factors for bovine TB/ M. Bovis
Surface proteins, mycolic acid
Necropsy of cow lung showed these lesions, what are they and what caused
tubercles, caused by M. Bovis
When are clinical signs evident in bovine TB
Advanced disease
What are some signs of advanced pulmonary TB in cows
Cough, intermittent fever
If bovine TB spreads via blood or lymphatics what can it result in (3)
- Tuberculous mastitis
- Supramammary LN enlargement
- Facilitates spread of infection to calves
What is the standard test to dx bovine TB
Tuberculin skin test
The tuberculin skin test is based on ___
Delayed type hypersensitivity
What is injected in tuberculin skin test
Purified protein derivative (PPD tuberculin)
What does a positive tuberculin skin test look like
Hard swelling at injection site