23 Nontuberculous Mycobacteria, Nocardia, Legionella and Mycoplasma Flashcards
What is the second most common mycobacterial disease? Can it survive outside of a host?
- M. leprae- Hansen’s disease
- must be in a host
T-F-it is not important for treatment and public health to distinguish between NTM infection and one from M. tuberculosis?
False
T-F–non-tuberculous mycobacterium can cause disease in immune privileged individuals only?
False- healthy too
Large disfiguring lesions that are often painless are from what? What does it secrete that leads to nerve damage, immunosuppression and necrotizing adipose? Opportunistic or primary pathogen?
M. ulcerans
- secretes mycolactones
- It is an opportunistic pathogen
What often survives in biofilms in water supplies, cooling towers, fountains?
Legionella
What must legionella survive in in the natural world?
Inside amoeba or other protozoan inside the water
What are the 2 main forms of legionella?
replicative stage and mature intracellular form
T-F–detection of legionella in the water is definitive for an upcoming outbreak?
false- outbreak strains must be genotypical matched to strains found in the water supply
How are humans infected by legionella?
Droplets and survival occurs in macrophages
What is the unculturable bacteria? Does it have a cell wall? Significance?
- Mycoplasma
- no cell wall
- no beta-lactam antibiotics
What is the most common cause of community acquired pneumonia?
Mycoplasma pneumoniae
What is the main virulence factor of mycoplasma?
adherence- p1
T-F– most cases of M. ulcerans are transmitted person to person?
False
M. leprae is an infection of what? 5
skin, peripheral nerves, upper respiratory, eyes
Is numbness common in M. leprae? Why? Where does it start?
Yes 90%—there is significant nerve damage that leads to loss of sensation—begins in the extremities
Transmission of M. Leprae is done by droplets, but what is required?
Prolonged, close and frequent contact
Is risk of M. leprae higher with HIV?
No
M. leprae can be found in a paucibacillary form/stage and multibacillary form/stage. What are the 2 characteristics of each that differentiate?
Paucibacillary= low acid fast bacilli and intact cell-mediated immunity
Multibacillary= High AFB and symmetrical skin lesions
T-f–we have seen a dramatic increase in world disease burden of M. leprae?
False
[pockets are in Brazil China, Africa, Nepal, Philippines and Sri Lanka]
How long can the M. leprae be latent for? What is the doubling time?
- 30 years
- 12-14 day doubling time
What are the 3 main reservoirs of M. leprae?
human
nine-banded armadillo
[chimp, mangabey, monkey]
What does leprosy diagnosis entail? 3
- clinical signs/symptoms
- AFB microscopy
- Cannot be grown in culture
Where does M. leprae survive?
Macrophages and non-phagocytic cells (striated muscle, glial, schwann)
What is the multi drug treatment of M. leprae? Can M. bovis BCG be a good vaccine?
- dapsone, rifampicin, and clofazimine for 6-12 months
2. yes but not pursued heavily
T-f–m ulcerans is fast growing? has high mortality? and high morbidity?
False- slow growing
False- low mortality
True- high morbidity
Because m. ulcerans lesions are painless, most don’t cause serious permanent damage?
False–loss of limbs and organs
What is the % of m. ulcerans cases found in children? How many of those are disabled?
75% and 60% of those are disabled
What environment is conducive to m. ulcerans infections?
rural tropics, near stagnant water