Chlamydia

Question 1

Chlamydia morphology

Answer 1

Gram negative

obligate intracellular parasites

Question 2

Chlamydia species

Answer 2

C. trachomatis
C. pneumoniae

C. psittaci
C. abortus

Question 3

Developmental cycle

Answer 3

EB- infectious
RB- replicative
only growth inside a vacuole called inclusion inside infected cell
EB internalization, EB differentiates into RB, RB grows in contact with inclusion membrane
RB replicate, once inclusion is big enough, RB differentiate back into EB
inclusion and infected host cell lyse, or inclusion is exocytosed

Question 4

Characteristics of EB

Answer 4

spore like form
extracellular survival
infectious/transmissible form
condensed DNA
smaller
metabolically dormant

Question 5

Characteristics of RB

Answer 5

replicative form
larger
no infectious
decondensed DNA
capable of making own ATP or acquiring from host cell

Question 6

Virulence factors

Answer 6

Adherence
Type III secretion system- like a syringe, injects virulence factors directly into host cytosol
Auto-transport (type IV secretion system)- put polymorphic membrane proteins on surface for adhesion
C. trachomatis makes cytotoxins related to clostridial cytotoxins

Question 7

Types of pathologies

Answer 7

Primary infection- localized, inflammation
Chronic infection- localized scarring
disseminated infection- remote scarring

Question 8

C. trachomatis cause what type of disease (general)

Answer 8

Ocular infections

genital infections

Question 9

Ocular chlamydia trachomatis infections

Answer 9

Primary conjuctivitis
Chronic Trachoma (leading cause of preventable blindness
transmission: direct contact, house flies
antibiotic treatment, but antibiotic therapy has no effect past childhood

Question 10

Stages of ocular chlamydia trachomatis infections

Answer 10

inclusion conjuctivitis- acute inflammation
follicular conjuctivits- repeated infections leads to DTH response
Pannus- corneal inflammation, scar tissue, neovascularization
Trichiasis- scarring results in contraction of conjuctiva- eyelashes turn inward
eventually blindness in mid to late adulthood

Question 11

C. Trachomatis infection of newborn

Answer 11

Ophthalmia neonatorus- ocular infection acquired going through birth canal- hospital required to give antibiotic eye drops post delivery

Neonatal pneumonitis

Treatment: Erythromycin orally 14 days

Question 12

Genital Chlamydia trachomatis infections characteristics, immunity

Answer 12

asymptomatic or mild symptoms
asymptomatic or non-reporting men/woman are reservoirs
Antibody and cell mediated immune response
short live immune response- responsible for re-infection and persistent infection and no vaccine

Question 13

Chlamydia pneumonia general characteristics, general types of infections

Answer 13

very common- everyone has it at least once, often asymptomatic
primary infection- common cold like symptoms to atypical community acquired pneumona
chronic infection- exacerbation of chronic bronchitis, asthma, COPD
Disseminated infection- reactive arthritis, AAA, stroke, MS, Alzheimers, strong associated with atherosclerosis**

Question 14

C. pneumoniae treatment

Answer 14

Doxycycline**
Erythromycin
Quinolones (Levofloxacin)

Question 15

What has a strong association with astherosclerosis

Answer 15

Chlamydia pneumoniae infections

Question 16

C. pneumoniae diagnosis

Answer 16

usually not attempted

CF assay using genus specific antigens

Question 17

Chlamydia psittaci and chlaymedia abortus

Answer 17

widespread infection of domesticated and wild animals can cause a zoonotic infection in humans

Question 18

Avian C. psittaci

Answer 18

Psittocosis
EB from avian C. psittaci can last months in environment and highly infectious in aerosols
flu like illness to severe pneumonia like syndrome
can cause spontaneous abortion in pregnant women

Question 19

Avian C. psittaci diagnosis

Answer 19

Serology- method of choice

history of exposure to birds

Question 20

Treatment of C. psittaci

Answer 20

Doxycycline