Chlamydia and Chlamydophila

Question 1

Physical description of organism

Answer 1

• obligate intracellular parasite

- small genome; lacks metabolic genes and steals ATP

Question 2

Cell wall of organisms

Answer 2

• lacks MurNAc(not true PG), but has PBPs

- 15 servers based on LPS antigens

Question 3

Type of host cells

Answer 3

• eukaryotic host cells
• embryonated chicken eggs
• McCoy cells in monolayer tissue
• mouse brains

Question 4

Two forms involved in the life cycle of organism

Answer 4

Elementary bodies and Reticulate bodies

Question 5

Basic description of both forms

Answer 5

• elementary bodies: infective

- reticulate bodies: replicative

Question 6

Description of elementary bodies

Answer 6

• 0.3um diameter
• electron dense nucleoid
• tough membrane w/S-S

Question 7

Description of reticulate bodies

Answer 7

• 1.0um diameter
• diffuse EM staining
• fragile w/SH HS
• more ribosomes

Question 8

Clinical presentation of organism

Answer 8

1. Trachoma
   - infection at birth from infected canal or contact or vector
   - mucopurulent discharge, pannus formation(keratnized cornea), cornea obscuration and eyelid involvement(trichiasis)
   - irritation from eyelashes+pannus+bacteria lead to blindness

Question 9

Clinical presentation of organism

Answer 9

2. Inclusion conjunctivitis
   - similar to trachoma, not severe
   - neonate from infected birth
   - associated respiratory comps.

Question 10

Clinical presentation of organism

Answer 10

3. Neonatal pneumonia
   - shortness of breath, no fever
   - occur in newborn with incl. conjun.

Question 11

Clinical presentation of organism

Answer 11

4. Chlamydia
   - STD
   - Males
   a. nongonococcal urethritis
   b. epididymitis
   c. prostatitis
   d. normally self limiting
   - Females
   a. urethritis
   b. cervicitis
   - salpingitis/PID

Question 12

Clinical presentation of organism

Answer 12

5. Latent infection(lymphogranuloma venereum)
   - small abscess, and initially heals quickly
   - inguinal buboes follow
   - fever and pain
   - may turn black, never cervical LN
   - may become chronic lead to fibrous lymphatic restrictions or bowel obstructions

Question 13

Epidemiology of organism

Answer 13

• STD most common type in NA, SA, Eur

- Trachoma common where hot, dry areas with poor clean water

Question 14

Pathogenesis of organism

Answer 14

• invasivness is caused by elementary bodies, binding to host receptor
• pathogen mediated endocytosis via T3SS effectors that remodel cytoskeleton
• induce cytokines, IL1 and cause inflammation
• tend to remain in host cells

Question 15

Control of organism

Answer 15

• vaccine ineffective
• screening is key, PCR common
• azithromycin
• surgery or epilation for trichiasis
• tetracycline or macrolides

Question 16

Description of C. pneumoniae

Answer 16

• jumped to humans as a zoonosis from koalas?
• high infection rate but most asymptomatic
• mild URT disease may progress
• found in atherosclerotic plaques
• asthma, stroke, Alzheimers
• tretracycline might help

Question 17

Description of C. psittaci

Answer 17

• acute, severe pneumonia and sepsis with patchy, well-defined lung involvement
• always transmitted by contact with birds
• tetracycline