Mycobacterium Flashcards
mycobacterium has very long and complex ____
mycolic acid
is Mycobacterium reportable?
YES!- hugely important must report
Mycobacterium has a very _____ cell wall and is acid fast ____
lipid rich, acid fast positive
Does mycobacterium form spores?
no- it is non spore forming
True/False: Mycobacterium has flagella and capsule
False: Flagella and capsule are ABSENT from mycobacterium
True/False: Mycobacterium does not survive in the environment for very long
False: they are very heary and survive for very long periods of time in the environment due to their very lipid rich cell wall
Is mycobacterium gram positive or gram negative?
Gram positive
What is the best diagnostic test for Mycobacterium?
Acid fast stain
Acid fast positive- they resist discoloration
You’ll be able to see macrophages packed with mycobacterium
What other organism is a good differential for Mycobacterium?
Systemic fungi
Mycobacterium can be either ______ or ______ pathogens
obligate or opportunistic
What diseases are caused by mycobacterium?
Tuberculosis- most common
Paratuberculosis (Johne’s disease)- important in ruminants
Granulomatose disease
What lipid virulence factors does mycobacterium have that aids in intra macrophage survival?
Lipids, glycolipids, and peptidoglyolipids
Mycobacterium posses enzymes such as alkyl hydroperoxidase reductase that down regulates what?
the respiratory burst and the immune response in general
Glycolipid attribuites to the ____ factor
Cord
(bacteria form cords when grown in liquid medium)
Mycobacterium also produces ____ for iron acquisition
siderophores
Animal tuberculosis is a ____ disease
Reportable
True/False: You treat food animals for tuberculosis
FALSE- you DO NOT treat food animals for tuberculosis. You immediatly eliminate those animals
What type of inflammation does tuberculosis cause?
granulomatose
Mycobacterium tuberculosis is found in what species
humans and primates
Mycobacterium bovis is found in what species?
cattle, humans, primates
humans get this from contaminated milk
(picture shows tuberculosis in cattle with caseous necrosis)
mycobaterium avium is found in what species?
birds
Which subspecies of mycobacterium is the most common causitive agent of tuberculosis in poultry?
mycobacterium avium subspecies avium
What 4 species are known to be reservoirs for mycobacterium bovis?
white tail deer in USA- most important to know
badger
brush tailed possum
cape buffalo
How is tuberculosis transmitted?
respiratory tract and ailmentary routes
(inhalation or ingestion)
_____ zoonosis is also possible with Mycobaterium tuberculosis
reversible
humans can transfer the mycobacterium to the animals
What is the process if the organism is inhaled?
the mycobacterium can be taken in by macrophages and will start replicating within them and eventually reach the regional lymph nodes.
If strong immune response is evoked- the bacterial will be arrested in the lymph nodes. Granulomatose inflammation encapsulates the bacteria and shedding will not occur. In time, when the host gets stressed, the foci can open and release the live mycobacterium
If the immune response is weak- the mycobacterium will continue replicating in macrophages. Reaches other tissue, including mammary gland and can be released in milk. Bacteria released in feces and contaminates the environment
What type of vaccine do we need for mycobacteria?
cell mediated vaccine
We need to stimulate TH1
_____ can also release a lot of bacteria into the environment
Coughing
What is a tubercle?
central area of calcification
mycobacterium are associated with granulomatose lesions
If you are dealing with an immunosuppresed animal, that does not induce a cell mediated immune response, what kind of inflammation will occur?
Tuberculous pneumonia will occur and predominatly neutrophils will respond
Larger chance of rapid death and dissemination of the bacteria
In a cell mediated immunity, what kind of cells with dominate?
macrophages- can protect from dissemination
HOWEVER, can also aid in dissemination because tissue damage facilitates bacterial spread
What are some disease patterns of animal tuberculosis?
emaciation
enlarged lymph nodes
cough
diarrhea
What should be high on your differentials if you have a cow with nasty lesions in the spleen, liver lungs, and lymph nodes with caseous necrosis?
mycobacterium bovis
main agent causing tuberculosis in ruminants
(picture shows bovine tuberculosis)
What other types of mycobacterium have also been isolated in cattle other than mycobacterium bovis?
Mycobacterium avium- abortions
mycobacterium tuberculosis
If you do an acid fast stain and it is bovine tuberulosis positive, what should you see?
granulomatose inflammatory cells with acid fast organisms
True/False Horses are commonly infected with mycobacterium
False: horses are rarely infected
What mycobacterium are swine normally infected by?
Mycobacterium bovis
usually via the ailmentary route
what is the causitive agent for tuberculosis in swine and humans?
Mycobacterium avium subspecies hominissuis
What is the most common mycobacterium of dogs and cats?
Mycobacterium bovis
(dogs may also be infected with Mycobacterium tuberuclosis)
What disease does mycobacterium cause in dogs?
Marie’s disease
What mycobacterium are humans usually associated with?
Mycobacterium tuberculosis and mycobacterium bovis
What are the routes of transmission to humans?
Mycobacterium tuberculosis- airborne (ex. homeless shelters)
Mycobacterium bovis- ingestion of contaminated milk
What are the most common areas of lesions for mycobacteria?
liver, spleen, and lungs
These tissues are rich with macrophages, which is where mycobacteria can accumlate
Pathogenesis of mycobacterium in Birds
disseminate to liver and spleen - wide nodules are spread throughout the tissues
Tuberuolosis has high _____ in confined groups
communicability
What type of cattle are more resistant to tuberculosis and what type has a higher prevalence?
Zebu cattle- more reistant
dairy cattle- higher prevalence
Tuberculosis is more associated with the ______ immune response
cell mediated
(without it the disease is more likely to disseminate)
Vaccines (BCG) for tubercuolsis is focused on ______
infants
What can you use to disinfect a sample and isolate mycobacterium?
hypochlorite
True/False: Tubercle bacilli are very hardy
True
survive long periods in soil
resistant to many disinfectants
Laboratory diagnosis: Is it better to grow mycobacterium on media or do a molecular diagnosis?
molecular diagnosis
Grows very slow on media
What is the most common test done to look for tuberculosis?
Tuberculin Test (hypersensitivty)
Subcutaneous injection- fever
Conjuntival injection- conjunctivits
Intradermal route- local swelling
What is the downfall of the Tuberculin test?
False positives and false negatives are frequent
What do positive tuberculosis skind test results look like?
Like this:
What is the treatment for mycobacterium?
identification and elmination of infected animals
True/False: eradication of bovine, human, and avian tuberculosis will dimish infection hazards for other species
TRUE
What species is Johne’s disease most important in?
ruminants
(Guernsey, Jersey, and Shorthorn)
What is the causative agent of Johnes disease?
mycobacterium avium subspecies paratuberculosis
What does Johne’s disease cause?
wasting disease of ruminants
lesions in the GI tract. Does not allow absorption of nutrients which leads to loss of liquids
REPORTABLE
Who is the reservoir for Mycobacterium avium subspecies paratuberculosis?
symptomatic and asymptomatic wild and domestic ruminants, swine and rabbits
spread mainly through ingestion or contact with feces
Pathogenesis of Johne’s disease
- bacteria are ingested and uptaken by MALT and M cells in GI tract
- 12 month incuabtion period- slow growing
- Form tuberculoid lesions with granulomas
- Th1 lymphocyte recruitment
- if IFN gamma is compromisd there will be dissemination (possible for IFN gamma to maintain the bacteria in the tuberculin stage so it won’t disseminate)
- granulomatous reaction
- damage to the mucosl eptthelium (lepromatous stage)
What percent of John’es diseae progress to clinical diseases?
5%
malabsorption, protein loosing entropathy
What does Johnes disease cause in ruminants?
weight loss, diarrhea, enlarged lymph nodes
What age group is most susceptible to Johne’s disease?
young
disease is mostly due to stress factors
Is a vaccine used for Johne’s disease in the US?
no, because the vaccine interfere with the diagnosis (false positives)
Best way to diagnose Johnes disease
sample of ileocecal area
Ziehl neelsen stain- acid fast (positive rods)
What needs to be added to the media for Johnes disease to grow?
mycobactin- siderophore
_____ test are of high value because there are high antibody titers
serological
Johnes disease causes a _____ type hypersensitivity
delayed
Treatment for Johnes disease
eliminate infected animals
overall cleanliness techniques
______of milk is extremely important
pasteurization
Causative agent of Feline Leprosy
Mycobacterium lepraemurium
How is feline leprosy transmitted?
rodent bite
Feline leprosy causes mycobacterial infection of the ____ and is acid fast _____
skin
acid fast positive
Feline leprosy treatment
surgical excision of affected sites
True/False: Mycobacterium can also be present in reptilians, fish and amphibians associated with chronic type inflammation
True
True/False: all mycobacterium have a zoonotic risk
True
Which mycobacteria are found in aquatic organisms?
M. marinum
M. fortuitum
M. chelonae
Most common inflammation caused by mycobacterium
granuloma inflammation packed with acid fast positive bacilli
what is the zoonotic significance of the aquatic mycobacteria?
Fish handlers diease aka swimming pool granuloma
