Exam 2: Mycobacterium Flashcards
T/F. Mycobacterium are gram neg.
F. Positive
T/F. Mycobacterium do not have an outer memb
T
T/F Mycobacterium have mycolic acid in their cell wall
T
Contributes to the acid fast staining
Mycolic acid
Gram +, acid fast +, Rod shaped bacteria
Mycobacterium
Mycobacterium grow in aerobic/anaerobic conditions
Aerobic
Do mycobacterium survive in the environment well?
yes
Genus of historic importance in developed countries because of human and bovine tuberculosis
Mycobacterium
What spp of mycobacterium cause Johne’s Dz
M. avium subsp. paratuberculosis
Mycobacterium are intra/extracellular pathogens?
Facultative intracellular
What type of immunity protects animals against Mycobacterium?
Cellular immunity (Th1 resp.)
What is the pathogenesis of mycobacterium spp.
Chronic bacterial infections and granulomatous inflam.
Mycobacterium are facultative intracellular pathogens of _______.
Macrophages
What are the 3 virulence factors of Mycobact.
- Lipid rich- protection from IS
- Lipoarabinomannan
- Cell protein antigens
Virulence factor of mycobac. that inhibits the phagosome from fusing with the lysosome
Lipoarabinomannan
What are the 3 spp. of mycobac. that are obligate pathogens?
- M. tuberculosis complex
- M. avium subsp. paratuberculosis
- M. leprae
- M. lepraemurium
Which spp of Mycobac. causes mammalian TB?
M. TB complex:
- M. tuberculosis
- M. bovis
- M. africanum
- M. microti
Which spp. of mycobac. causes Avian TB?
M. avium subsp. avium
Which spp of mycobac. causes Leprosy?
M. leprae- human
M. lepraemurium- cat
Which spp. of mycobac, forms caseous granulomas
- M. tuberculosis
2. M. bovis
What is the transmission of TB?
Inhalation and ingestion
What is the pathogenesis of TB?
- Local multiplication
- uptake by macrophages
- Migration to lymph node
- lymphadenitis
_____ IR is important in the destruction of bacilli
Cell mediated
What type of hypersensitivity is seen with TB?
type 4 (delayed type)
The classic lesion of TB. Well organized granulomas of varying sizes
Tubercles
What are the two possible centers of tubercles?
- Hard tubercle: solid packed with epithelioid macrophages
2. Soft Tubercle: caseous necrosis
Who is the main reservoir for M. tuberculosis
Humans
What spp. are effected by M. tuberculosis
humans, dogs, cats, pigs, primates
What are some methods of diagnosing M. tuberculosis
- Radiographs
- AFB staining, culture, PCR of sputum
- TB test (mantoux test)
T/F. TB is a treatable and cureable Dz
T
What is the standard treatment of TB?
6 months course of antimicrobial drug combinations (mix of primary and secondary drugs)
What are the 4 primary TB drugs?
- Isoniazid
- Rifamycins
- Ethambutol
- Pyrazinamide
What are teh 2 categories of secondary drugs used to tx TB?
- Aminoglycosides
2. Fluoroquinolones
Why must you use combination drug therapy when treating TB?
- bacteria n lesion can be intra or extracellular
- Grow in log pahse and exhibit quiescent phase
- Drug resistance
- poor distribution to walled off lesions
What is MDR TB?
Multidrug resistant TB- resistant to at least isoniazid and rifampin
What is XDR?
Extensively Drug resistant TB- Resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of the 3 inj second line drugs
What is the human vaccine for TB?
BCG (bacillus Calmette Guerin)
What Mycobac. causes zoonotic TB?
M. bovis
Transmission of M. bovis
ingestion
inhalation
contact with mucus memb
What is the main portal of entry for M. bovis
GIT
M. bovis is maintained primarily in _____ spp., but has the broadest host range of all TB organisms
Bovine
how long can M bovis survive outside of the host?
few weeks
T/F. there are significant differances in M bovis and M. tuberculosis infections
F. indistinguishable
____ transmission of M bovis is most common among cattle
Aerosol
T/F. M bovis can be spread in milk
T
list some Dx of M bovis
- TB test
- Gamma IFN blood test
- Clinical dz + Histopathology
- Direct Acid-fast stain
- Culture
- DNA based methods
What is the tuberculin hypersensitivity skin test?
inj. animal with M. bovis protein, look for swelling of inj site in 72 hrs.
T/F. cows infected with M. bovis can be treated and cured
F. not recommended to tx, culling is best option
T/F. there are no vaccines available for M bovis
T
What are the 5 elements of bovine TB eradication programs?
- Dz surveillance
- Pre and post movement cattle testing
- Removal of cattle exposed to TB
- Tracing source
- Wildlife control
A chronic, progressive granulomatous enteritis in cattle infected with M. avium subsp paratuberculosis
Johne’s Dz
Who is the primary host of Johne’s Dz
Cattle
What is the pathogenesis of Johnes Dz
ingestion of contaminated milk or in utero. found in macrophages in the intestine and ln. will lay dormant for 2-5 years
symptoms of Johne’s Dz
diarrhea and wt. loss
3 Dx methods for paratuberculosis
- Acid fast stain
- Culture
- PCR
Dx method for Johne’s dz commonly used in cattle herds to detect humoral immune response to MAP
ELISA
When do false negative ELISAs occur when testing for Johne’s Sz
In advanced stages of dz due to anergy
How do yo treat Johne’s Dz
Not recommended to tx
List some prevention measures for Johne’s dz
- culling infectd
- detection of asymptomatic carriers
- Separation of calves at birth
- pasture rotation
Is their a vaccine available for Johne’s dz
Yes, restricted due to reactions
In Johne’s dz who is most susceptible?
Young
What 3 subsp. of Mycobacterium avium intracellular complex?
- subsp. avium
- subsp. sylvactium
- subsp. hominisuis
disease caused by M. ulcerans
Buruli ulcer
one of the fequent mycobacteral diseases in humans in certain geographic regions
Buruli ulcer
What causes tissue necrosis in buruli ulcer?
cytotoxin mycolactone
Mycobacterium that causes leprosy or hansen’s dz
M. leprae
how is M leprae shed?
through the nose, not the skin
What is the only known animal reservoir for M leprae?
9 banded armadillo
What is the diff. between tuberculoid leprosy and lepromatous leprosy?
TL (paucibacillary)- few acid fast positive bacilli in the lesion
LL- (multibacillary)- no cell mediated response, severe dz with numerous acid fast positive bacilli
What is M. lepraemurium
Feline and murine leprosy
What does it mean when an organism is fastidious
hard to culture
what is the result of M lepraemurim infection
granulomatous dermatitis and panniculitis
How do you dx M lepraemurium?
Direct staining
culture
biopsy and histopathy
PCR
In Gram stain of M. lepraemurium positive/negative stained bacilli are generally observed
negative
T/F In a gram stain fof M lepraemurium gram negative bacilli are commonly observed
F. negative stained not gram negative
How do you tx M. lepraemurium
- surgical excision
2. Rifampin, Clarithromycin, Clofazimine
What abx can be given to dogs with M. lepraemurium?
Doxycycline
What are the 2 categories of Saprophytic Mycobacterium
- rapid growing
2. slow growing
type of mycobacterium that causes chronic, non-healing cutaneous lesions that do not respond to common antibacterial tx
Saprophytic mycobacterium
