Mycoplasma-Vishy

Question 1

What are the basic characteristics of Mycoplasma?

Answer 1

1. Lack cell wall (permanent L-form bacteria).
2. Contain cell membrane w/ sterols though.
3. 0.25μm. (pretty small)- Pass thru syringe filters into the filtrate. Have to use special membrane filters.
4. Can grow in liquid and agar based media.
5. Replicate thru binary fission.
6. Produce “fried egg” colonies on agar.
7. Extracellular and noninvasive. ***Exception: M. penetrans (intracellular pathogen) in HIV patients.

Question 2

How do you diagnose Mycoplasma?

Answer 2

1. Bedside test – cold agglutinins.
   • Antibodies (IgM) produced vs. mycoplasma cross-react w/ O blood group RBCs.
2. PCR, DNA hybridization, or culturing (best diagnostic tests).

Question 3

What is the pathogenesis of Mycoplasma?

Answer 3

1. Attach to ciliated cells w/ tapered end and adhesins.
2. Destroy ciliated epithelial cells thru production of ROS and inhibition of catalase in the host cells.
3. Produces superantigens which bind to MHC class II and T-cell producing excess quantities of cytokines.

Question 4

What is the treatment for Mycoplasma?

Answer 4

Not w/ PCN or Cephalosporins.

Use Tetracyclines and erythromycin, no vaccine.

Question 5

What does Mycoplasma pnuemoniae cause primarily? What does it look like? When does it occur? What else can it cause? Treatment? Transmission? Symptoms?

Answer 5

Causes atypical pneumonia
Has a mulberry appearance.
Common during summer season and fall.
Also causes: otitis media and other respiratory infections.
Treat w/ erythromycin.
No animal reservoir. (human-to-human transmission)
Less than 10% develop infection.
• Of those only 30% get atypical pneumonia. The other 70% get bronchitis.
Symptoms: cough and white sputum.

Question 6

What does Mycoplasma hominis cause? What media does it require? What does it look like?

Answer 6

Causes pelvic inflammatory disease.
Grown in media w/ arginine.
Looks like a fried egg.

Question 7

What does Ureaplasma urealyticum cause? What does it produce (used in diagnosis)?

Answer 7

Causes non-gonococcal urethritis in men.
Produces urease (used in diagnosis).

Question 8

Which Mycoplasmas may have vertical transmission? When does it occur?

Answer 8

There is possible vertical transmission of hominis and urealyticum (occur during birth).