Legionella and Mycoplasma

Question 1

What is the general physical description of Legionella pneumophila? (gram, shape)

Answer 1

Gram-negative, pleomorphic rod

Question 2

Does Legionella pneumophila grow intra or extracellularly?

Answer 2

It grows intracellularly

Question 3

Where in nature is Legionella pneumophila most commonly found?

Answer 3

In the water of cooling towers, resides in free-living amoeba or free-living in biofilms

Question 4

What is the principal symptom in serious cases of infection with Legionella?

Answer 4

atypical pneumonia

Question 5

What is the more mild form of Legionella infection called?

Answer 5

Pontiac fever

Question 6

How is infection with Legionella acquired?

Answer 6

airborne transmission from environmental contamination

Question 7

Is Legionella communicable? (can you get it from an infected person)

Answer 7

No, it is only acquired from environmental sources such as stagnant water in air conditioning and heating units

Question 8

What is the incubation period of Legionella?

Answer 8

2-10 days

Question 9

What cellular reactions are characteristic of the early stage of infection with Legionella?

Answer 9

induction of apoptosis in macrophages and alveolar epithelial cells

Question 10

What cellular reactions are characteristic of the second stage of infection with Legionella?

Answer 10

Necrosis induced by pore-forming activity in infected phagocytes

Question 11

Is Legionella invasive?

Answer 11

Yes, it can disseminate from the lung and cause invasive disease

Question 12

What type of medium can Legionella be grown on?

Answer 12

charcoal yeast extract with iron and cysteine

Question 13

What is the test of choice for the diagnosis of Legionella infection?

Answer 13

Direct flourescent antibody test

Question 14

In what samples would you detect Legionella antigens?

Answer 14

Urine samples

Question 15

What should you keep in mind when testing antibody levels to Legionella in your patient’s blood?

Answer 15

Take 2 samples 3-6 weeks apart

Question 16

What is the smallest replicating bacteria?

Answer 16

Mycoplasma pneumoniae

Question 17

What structural feature sets Mycoplasma apart form all other bacteria? How does this impact antibiotic choice?

Answer 17

No cell wall so resistant to antibiotics that target the cell wall

Question 18

Will mycoplasma grow on cell-free media?

Answer 18

Only if sterols and other nutrients are provided by yeast extract and animal serum.

Question 19

Will mycoplasma grow on standard laboratory medium?

Answer 19

No

Question 20

Is immunity from mycoplasma life-long?

Answer 20

No, may acquire the disease again after 5-10 years

Question 21

What disease is caused by Mycoplasma infection?

Answer 21

atypical pneumonia with gradual onset

Question 22

What is the difference between typical and atypical pneumonia seen on X-ray?

Answer 22

Typical has lobar arrangement, atypical does not and includes spotty points of infection

Question 23

What are the 3 organisms that cause atypical pneumonia?

Answer 23

Legionella, Mycoplasma, Chlamydia pneumoniae

Question 24

Do extrapulmonary infections occur from Mycoplasma infection? If so, what is the system affected?

Answer 24

Yes, CNS

Question 25

How is mycoplasma transmitted?

Answer 25

By aerosols, usually from close playmates

Question 26

What does Mycoplasma use to attach to respiratory epithelium? What does it do there?

Answer 26

Adhesins including P1 complex; induces cilliotosis (ciliostasis, right ??) resulting in necrosis

Question 27

What does Mycoplasma produce that leads to oxidative damage and inflammation

Answer 27

hydrogen peroxide

Question 28

How is Mycoplasma treated?

Answer 28

Antibiotics that interfere with protein synthesis such as macrolides and tetracyclines

Question 29

Is there a vaccine for Mycoplasma? If so, what type is it?

Answer 29

No vaccine is available

Question 30

What diagnostic tests are most effective for Mycoplasma?

Answer 30

PCR and cold agglutination with serum IgM antibodies