Test 80    (microbiology)

1. In toxocariasis:

a. the infestation is acquired from both dogs and cats
b. infestation occurs through ingestion of larvae
c. tractional retinal detachment is a cause of poor vision
d. intraocular calcification is a common feature of ocular 
    toxocariasis
e. steroid is contraindicated

Answera.T   b.F  c.T   d.F   e.F
Toxocariasis can be acquired from dogs (Toxocara cani) and cats (Toxocara cati).
Intraocular calcification is uncommon in toxocariasis
and is a useful sign in differentiating it from retinoblastoma.
Steroid is used to reduce intraocular inflammation.

2. Onchoceriasis:

a. is caused by a protozoan
b. transmitted by the bite of fly
c. is confined to the African continent
d. ocular involvement results from lymphatic migration of the parasites
e. can be treated with ivermectin 

Answera.F   b.T   c.F   d.F   e.T
It is caused by a nematode.
It is transmitted by the bite of the female Simulium fly.
Ocular involvement results from 
subcutaneous migration of the worms.

3. Propiobacterium acnes:

a. is a Gram positive bacilli
b. is an anaerobic bacteria
c. is a common commensal of the conjunctiva
d. is an important cause of acute post-operative 
    endophthalmitis
e. is sensitive to vancomycin

Answera.T   b.T   c.T   d.F   e.T
It is a recognized cause of delayed postoperative endophthalmitis.

4. The following Gram negative bacteria are known to cause
    corneal ulcer:

a. Pseudomonas aeruginosa
b. Moraxella lacunata
c. Bacillus brevis
d. Klebsiella pneumoniae
e. Serratia marcescens

Answera.T  b.T  c.F  d.T   e.T
All the bacteria are Gram negative except 
for Bacillus brevis which is Gram positive

5. The following are true about culture media for microbes:

a. Lowensten-Jensen is used to isolate mycobateria
b. thioglycolate broth allows only anaerobes to grow
c. MacConkey agar prevents the growth of Gram 
    negative bacteria
d. Sabouraud's culture is useful for culturing fungal 
    infection
e. Thayer-Martin's media is used to isolate gonococcus

Answera.T   b.F   c.F   d.T   e.T
Thioglycolate broth allows both anaerobes and 
aerobes to grow. Anaerobes grow below the
surface while the aerobes grow on the surface of the broth.
MacConkey agar is used to isolate Gram negative 
bacteria. Gram positive bacteria will not grow on the agar.

 
 

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