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2 PID Unit > 23 Nontuberculous Mycobacteria, Nocardia, Legionella and Mycoplasma > Flashcards

23 Nontuberculous Mycobacteria, Nocardia, Legionella and Mycoplasma Flashcards

1
Q

What is the second most common mycobacterial disease? Can it survive outside of a host?

A
  • M. leprae- Hansen’s disease

- must be in a host

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2
Q

T-F-it is not important for treatment and public health to distinguish between NTM infection and one from M. tuberculosis?

A

False

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3
Q

T-F–non-tuberculous mycobacterium can cause disease in immune privileged individuals only?

A

False- healthy too

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4
Q

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?

A

M. ulcerans

  • secretes mycolactones
  • It is an opportunistic pathogen
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5
Q

What often survives in biofilms in water supplies, cooling towers, fountains?

A

Legionella

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6
Q

What must legionella survive in in the natural world?

A

Inside amoeba or other protozoan inside the water

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7
Q

What are the 2 main forms of legionella?

A

replicative stage and mature intracellular form

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8
Q

T-F–detection of legionella in the water is definitive for an upcoming outbreak?

A

false- outbreak strains must be genotypical matched to strains found in the water supply

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9
Q

How are humans infected by legionella?

A

Droplets and survival occurs in macrophages

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10
Q

What is the unculturable bacteria? Does it have a cell wall? Significance?

A
  • Mycoplasma
  • no cell wall
  • no beta-lactam antibiotics
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11
Q

What is the most common cause of community acquired pneumonia?

A

Mycoplasma pneumoniae

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12
Q

What is the main virulence factor of mycoplasma?

A

adherence- p1

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13
Q

T-F– most cases of M. ulcerans are transmitted person to person?

A

False

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14
Q

M. leprae is an infection of what? 5

A

skin, peripheral nerves, upper respiratory, eyes

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15
Q

Is numbness common in M. leprae? Why? Where does it start?

A

Yes 90%—there is significant nerve damage that leads to loss of sensation—begins in the extremities

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16
Q

Transmission of M. Leprae is done by droplets, but what is required?

A

Prolonged, close and frequent contact

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17
Q

Is risk of M. leprae higher with HIV?

A

No

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18
Q

M. leprae can be found in a paucibacillary form/stage and multibacillary form/stage. What are the 2 characteristics of each that differentiate?

A

Paucibacillary= low acid fast bacilli and intact cell-mediated immunity

Multibacillary= High AFB and symmetrical skin lesions

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19
Q

T-f–we have seen a dramatic increase in world disease burden of M. leprae?

A

False

[pockets are in Brazil China, Africa, Nepal, Philippines and Sri Lanka]

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20
Q

How long can the M. leprae be latent for? What is the doubling time?

A
  • 30 years

- 12-14 day doubling time

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21
Q

What are the 3 main reservoirs of M. leprae?

A

human
nine-banded armadillo
[chimp, mangabey, monkey]

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22
Q

What does leprosy diagnosis entail? 3

A
  • clinical signs/symptoms
  • AFB microscopy
  • Cannot be grown in culture
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23
Q

Where does M. leprae survive?

A

Macrophages and non-phagocytic cells (striated muscle, glial, schwann)

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24
Q

What is the multi drug treatment of M. leprae? Can M. bovis BCG be a good vaccine?

A
  1. dapsone, rifampicin, and clofazimine for 6-12 months

2. yes but not pursued heavily

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25
Q

T-f–m ulcerans is fast growing? has high mortality? and high morbidity?

A

False- slow growing
False- low mortality
True- high morbidity

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26
Q

Because m. ulcerans lesions are painless, most don’t cause serious permanent damage?

A

False–loss of limbs and organs

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27
Q

What is the % of m. ulcerans cases found in children? How many of those are disabled?

A

75% and 60% of those are disabled

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28
Q

What environment is conducive to m. ulcerans infections?

A

rural tropics, near stagnant water

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29
Q

What is the characteristic histopathology of M. Ulcerans? how long do you have to culture? anything more sensitive?

A
  1. extracellular acid fast bacilli
  2. 6-8 weeks
  3. PCR for IS2404
30
Q

What are 5 characteristics of mycolactones?

A 
Diffusable
Many varieties
Necrotizing Adipose
Immunosuppressive
Nerve Damage
31
Q

What antibiotic treatment is given for M. ulcerans? Other treatment plans/options

A
  • Rifampicin and streptomycin- 8 weeks

- surgery +/- grafting, self heal, BCG vaccine

32
Q

What bacteria…opportunistic, symptoms 2-4 weeks post infections, arthritis, aquatic trauma, natural host is fish or frogs?

A

M. marinum

33
Q

Is M. avium, M. intracellulare and M. kansasii fast growing?

34
Q

Is M. fortuitum, M. chelonae and M. abscessus slow growing?

35
Q

What are the Runyon groups I-IV?

A

I=photochromogens
II=scotochromogens
III=nonphotochromogens
IV= fast growers

36
Q

What is the M. avium complex MAC? what common type of infections? where are infections coming from?

A
  1. M. intracellular and avium
  2. pulmonary infection in immunocompromised (can have GI infections too)
  3. environmental sources- no person to person
37
Q

For NTM infections what are the 4 common laboratory tests to speciate?

A
  1. biochemical tests
  2. Molecular probes
  3. DNA sequence (16sRNA, genome)
  4. Matrix-Assisted laser desorption/ionization-time of flight MALDI-TOF
38
Q

What is a ubiquitous aerobic filamentous bacteria that is saprophytic and lives in soil or water?

A

Nocardia > 50 species

39
Q

T-F Nocardia is a primary pathogen?

A

False–needs severely immunocompromised host

40
Q

80% of nocardia presents as? other 20%?

A

80%- invasive pulmonary, disseminated, brain abcess

20%- cellulitis

41
Q

Which nocardia species is most responsible for invasive infections? cutaneous infections?

A

invasive=asteroides

cutaneous=brasiliensis

42
Q

What does gram stain of nocardia look like? Acid fast stain?

A

gram-stain= weakly positive rods/filaments
Acid fast stain=positive [differentiates from actinomyctetes]

[it is important to note that Nocardia must be suspected to culture]

43
Q

What is the drug therapy [3] for Nocardia? Resistance is a growing concern…which strain is of resistant?

A
  1. Sulfonamide, ceftriaxone, amikacin

2. N. farcinica

44
Q

Why isn’t Nocardia colonization in the laboratory not necessarily sign of invasive infection?

A

can mean laboratory contamination, may exist as saprophytes on the skin and upper respiratory tract

45
Q

What is an aerobic, gram-negative rod, slow growth on BYCE media bacteria? colony appearance?

A

Legionella

-colonies look like ground glass

46
Q

Is legionella opportunistic? how many species? serogroups?

A

yes, 48, 90

47
Q

What legionella species is reported in 90% of cases?

A

legionella pneumophila

48
Q

What is interesting about many of the species names of legionella?

A

named after outbreak location

49
Q

How do we know a legionella like amoeba pathogen is not legionella?

A

they do not grow on culture

50
Q

What is the reservoir of legionella?

A

acquatic environment

  • biofilms on manmade
  • intracellular in amoebas in natural lakes etc.
51
Q

When does transmission occur for legionella?

replication?

A
  • limited nutrients

- abundant nutrients

52
Q

2 modes of acquiring legionella from the environment? person to person?

A

inhalation and aspiration

no person to person

53
Q

What are the risk factors for legionella infection?

A
  • Immunocompromised
  • heavy smoker
  • over age of 50
  • recent travel
54
Q

Is pontiac fever or légionnaires self limiting and non fatal respiratory infection?

55
Q

What are the symptoms of legionnaires and how many deaths in US?

A

fever, myalgia, cough pneumonia

8000-18000

56
Q

How to diagnose legionella?

A 
Direct Fluorescent antibody
Urine antigen
PCR
Culture Buffered Charcoal Yeast Extract (BYCE)
[Must have culture plus UA or PCR]
57
Q

What type of antibiotics are needed for legionella? drug of choice for kids?

A

high intracellular concentrations

azithromycin

58
Q

What favors amplification in nosocomial legionella disease?

A

old and complex plumbing systems

59
Q

Does legionella survive in 50-55C? 60C?

A

Yes, No [optimum is 35-45]

60
Q

What are 5 characteristics of the Mollicutes class because they don’t have a cell wall?

A
  1. fragile
  2. don’t gram stain
  3. contain mammal like membrane
  4. No particular morphology
  5. can not be treated with cell wall active drugs
61
Q

What mycoplasma causes bacterial vaginosis?

A

Mycoplasma hominis

62
Q

What mycoplasma causes urethritis?

A

genitalium, and urealyticus

63
Q

What does mycoplasma fermentans cause?

A

flu-like illness and pneumonia

64
Q

What 3 diseases does mycoplasma pneumonia cause?

A
  1. Primary atypical pneumonia
  2. Tracheobronchitis
  3. Pharyngitis
65
Q

T-f–mycoplasma pneumoniae has a short incubation period and long period of infectivity?

A

False- both are long periods

66
Q

Does M. pneumoniae demonstrate seasonality?

67
Q

What is the most common cause of pneumonia between 5 and 20 years?

A

M. pneumoniae

68
Q

What are the onset symptoms of M. pneumoniae pneumonia? later symptoms?

A

onset=fever, headache, sore throat, non-productive cough!!, and malaise
Later= paroxysmal cough, pain , blood maybe

69
Q

Chest x ray appears as what in M. pneumoniae? What is the traditional testing for diagnosis?

A
  1. striking consolidation which is odd for unremarkable lung sounds
  2. serological testing or cold agglutinin but is not generally performed
70
Q

Where does M. pneumoniae adhere? how

A

Base of cilia, P1 adhesion

71
Q

What are common antibiotics for M. pneumoniae?

A

doxycline, macrolides, or fluoroquinolones

2 PID Unit (13 decks)

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