Mycoplasma + Legionella

Question 1

Look up Moraxella catarrhalis

Answer 1

GN diplococci

Otitis media
sinusitis
Pharyngitis

Question 2

Atypical pneumoniae x ray

Answer 2

diffuse peribronchial pulmonary infiltrates

• highly contagious

(as opposed to lobar with typicals)

Question 3

Atypical pneumo. organisms

Answer 3

1. Mycoplasma
2. Legionella
3. Chlamydia
4. Virus (Influenza, CMV, RSV, adenovirus)

*strep pneumo is most comm cause of CAP

Question 4

Mortality of mycoplasma pneumoniae

Answer 4

1%

Question 5

Target of M. pneum in PCR

Answer 5

P1: terminal attachment protein to CILATED EPITHELIAL CELLS
- when tip structure comes in contact with epith cells, ciliostasis occurs and allows mucus to accumulate, facilitates microbial contamination of lower resp tract.

Question 6

Top 3 clinical manifestations of M. pneumo if not asymp:

Answer 6

1. Extrapulmonary manifestations (25-50)
2. Upper Resp. Tract - pharyngitis, otitis media, tracheobronchitis
3. Hematologic - hemolytic anemia (50%)

Question 7

Toxin of M. pneumo

Answer 7

CARDS Toxin

• seq homology with S1 subunit of pertussis toxin
• has ADP ribosylating activity
• significant virulence factor

Question 8

Cold agglutins

Complement fixation

Answer 8

autoantibodies that form on RBCs

Complement: Get pts sera used for epidemiology

*both are not useful, take too long

Question 9

dxing M. pneumo

Answer 9

1. a combination of PCR and serology

also
2. ELISA

Question 10

What can you give to tx M. pneumo if macrolide resistant?

Answer 10

Doxycycline,
FQ,

levofloxacin,
moxifloxacin
*PCN ineffective since no cell wall

Question 11

How to detect legionella

Answer 11

LPS Antigen detection in urine

Grow on charcoal yeast extract culture (with iron and cysteine)

Direct flourescent antibody staining on culture of sputum to S1

Question 12

Legionnaire’s disease vs Pontiac fever caused by Legionella pneumophila

• Fatality
• Attack rate
• effects on lungs
• other organ systems affected

Answer 12

Legionnaires:

• 20% fatality
• attack rate: 1-5%
• Unilateral, lobar - Pneumonia, pleural effusion
• CNS, GI

Pontiac:

• No fatality
• Attack rate: 95%
• Pleuritis (no pneumonia)
• None

Question 13

Intracellular bacteria that grow in a specialized endosome

Answer 13

1. Legionella
2. Toxoplasma gondii
3. psittici

Question 14

Intracellular bacteria that escape from the phagosome

Answer 14

1. Listeria
2. Rickettsia
3. Trypanosoma cruzi
4. Shigella

Question 15

Intracellular bacteria that survive in a phagolysosome

Answer 15

1. Leishmania
2. M. Leprae

*most insidious of intracellular growth

Question 16

Transmission of legionella by water

Answer 16

Potable (spec. for direct hu use)

• showers
• tap water
• respiratory care equipment

Question 17

Do mycoiplasmas synthesize cholesterol?

Answer 17

Nope. PM contains sterols

Question 18

Transmission of M. pneumoniae

Answer 18

Resp. droplets

- attackes to ciliated epithelial cells in trachea and bronchi of lower resp. tract.

Question 19

Unique cytoskeletal structure of M. pneumo

Answer 19

participates in binary division and gliding motility

- has elongated shape when it attaches to surfaces (ciliated epithelium)

Question 20

How does Legionella evade host defenses?

Answer 20

1. Living w/in macrophages (facultative intracellular)

2. Inhibits endosome-lysosome fusion

Question 21

Incidences of legionella occur more at what times of the year?

Answer 21

late summer, early fall