TEST 2 Bugs 3 PART 1 of 2

Question 1

What is the life cycle of Chlamydia?

Answer 1

• Extracellular form = elementary body (EB)
  
  • Infectious form
  • Metabolically inactive
  • Bind to epithelial cell receptors stimulating endocytic uptake.
• Intracellular form = reticulate body (RB)
  
  • Metabolically active
  • Uses host cell’s ATP for energy and form inclusion

Question 2

Describe traits of Chlamydia

Answer 2

• Obligate intercellular bacteria (cannot make ATP or many amino acids)
  
  • Energy parasits
• Lack peptidoglycan (no NAM)
• Have inner and outer membranes = gram negative
  
  • Not seen well on gram stain too small
• Insensitive to B-lactam antibiotics
• Treated with azithromycin or doxycycline.
• Major outer membrane protein (MOMP) has a variable region which determines the serotypes (serovars).

Question 3

Chlamydia trachomatis infections

Trachoma

Answer 3

• Serotypes A, B, Ba, and C
• Major cause of blindness in Asia and Africa
• Endemic among Native Americans in SW US.
• Spread by direct contact (need repeat infections).
• Invades epithelium of the conjunctiva → chronic follicular kerato-conjunctivitis.
  
  • Follicular scarring → inturned eyelashes, corneal scarring and blindness.

Question 4

Chlamydia trachomatis infections

Lymphogranuloma venereum

Answer 4

• Serotypes L1, L2 and L3:
• STD prevalent in Africa, Asia, and south america.
• Primary infection: painless genital ulcer, fever, headache, myalgia.
• Secondary infection: inflammation/swelling of lymph nodes (buboes), with systemic spread.
• Tertiary infection: Ulcers, fistulas, genital elephantiasis.

Question 5

Chlamydia trachomatis infections

Proctitis

Answer 5

Anorectal pain, discharge, tenesmus, and constipation

Question 6

Chlamydia trachomatis infections

Serotypes D-K, B and Ba