Mycoplasma pneumoniae

Question 1

biology?

Answer 1

Smallest free living organism

No cell wall or peptidoglycan (so poor gm stain)

Cell membrane has cholesterol

anaerobe

Non-motile

Question 2

how does it look on Eaton’s agar?

Answer 2

“Fried egg” colonies

Question 3

what does it need to grow?

Answer 3

cholesterol

Question 4

Epidemiology?

Answer 4

Human-to-human aerosol transmission

Question 5

MCC of what?

Answer 5

Community-acquired atypical pneumonia

Question 6

what is characteristic of the tip organelle of mycoplasma?

Answer 6

Multiple adhesion factors are located

highly specialized to tightly adhere to host epithelium

Question 7

Pathogenesis?

Answer 7

• Tip organelle orients to attach to epithelial cell surface in respiratory track.
• Attachment causes cilia arrest, leading to epithelial cell necrosis
• Bacteria are able to replicate using released cell components (cholesterol)
• Very little inflammation (no cell wall components!)
• Cell membrane resembles host because of cholesterol so triggers auto-reactive antibodies

Question 8

how do you know the person is a Chronic carrier?

Answer 8

coughing with no fever

Question 9

Clinical Disease of Mycoplasma?

Answer 9

“Walking Pneumonia”

Question 10

how does walking pneumonia present?

Answer 10

• Non productive (no exudate) Long lasting cough (2-3 weeks)
• X-ray shows small areas of infection or “Patchy infiltrates” with no leukocytes

Question 11

what differentials or other diseases can also look like walking pneumonia?

Answer 11

• Viral pneumonia
• Chlamydia pneumoniae*

Question 12

Patients develop self-reactive antibodies against what?

how is it measured?

Answer 12

cholesterol (anti-RBC), which are measured with cold agglutinin test.

Question 13

what is the treatment for mycoplasma?

Answer 13

Macrolides: Erythromycin