Microbiology

Question 1

name the types of gram positive cocci

Answer 1

strep and staph

Question 2

what are the types of gram negative bacteria

Answer 2

cocci (e.g. neisseria)
cocci-bacilli (H. influenzae)
bacilli (pseudomonas)

Question 3

what is an infection of the cornea called

Answer 3

keratitis

Question 4

what is an infection of the entire globe called

Answer 4

endophthalmitis

Question 5

when do you always refer bacterial conjunctivitis

Answer 5

when it affects a neonate (under 2 weeks)

Question 6

what organisms can cause bacterial conjunctivitis in neonates

Answer 6

staph aureus
neisseria gonorrhoeae
chlamydia trachomatis

Question 7

what organisms commonly cause bacterial conjunctivitis

Answer 7

staph aureus, strep pneumoniae, haemophilus influenzae

Question 8

what organism commonly causes bacterial conjunctivitis in children

Answer 8

haemophilus influenzae

Question 9

how do you treat bacterial conjunctivitis

Answer 9

swab 
topical antibiotic (chloramphenical) drops/ ointment

Question 10

when do you not give chloramphenicol

Answer 10

if history of aplastic anaemia or allergy

Question 11

when should you be suspicious of a cholramphenical allergy

Answer 11

is symptoms of bacterial conjunctivitis get worse (redder and itchy)

Question 12

what commonly causes viral conjunctivitis

Answer 12

adenovirus, herpes simplex, herpes zoster

Question 13

what is the difference in presentations of bacterial and adenoviral conjunctivitis

Answer 13

viral wont usually have discharge

Question 14

what is the treatment for adenovirus conjunctivitis

Answer 14

usually self limiting

Question 15

what is the presentation of herpes simplex conjunctivitis

Answer 15

can get vesicle around eye

Question 16

what is the presentation of herpes zoster conjunctivitis

Answer 16

shingles of the ophthalamic trigeminal nerve
vesicles in dermatome

(aka herpes zoster ophthalmicus)

Question 17

what is the usual presentation of chlamydial conjunctivits

Answer 17

often chronic- conjunctivitis that doesnt respond to topical antibiotics

suspect it in bilateral conjuctivitis in young adults

may have symptoms of urethritis, vaginitis

Question 18

what is the appearance of chlamydia conjunctivitis

Answer 18

follicular, grains of rice appearance under the lid

Question 19

what does the folliclular appearance of chlamydial conjunctivitis cause

Answer 19

subtarsal scarring (damage to the cornea)

Question 20

what is the outer lining of the cornea continuous with

Answer 20

the conjunctivia

Question 21

what is a hypopyon

Answer 21

leukocytic exudate in the anterior chamber of the eye (within cornea)

Question 22

what is a hypopyon seen in

Answer 22

keratitis- very serious, sight threatening

Question 23

what is the treatment for bacterial keratitis

Answer 23

need admitted for hourly drops and daily review

Question 24

what is bacterial keratitis usually seen with

Answer 24

other corneal pathology or contact lens wear

Question 25

what us a corneal ulcer

Answer 25

keratitis

Question 26

what viruses cause microbial keratitis

Answer 26

herpes and adenovirus

Question 27

can viral keratitis happen in a normal eye

Answer 27

yes, unlike bacterial keratitis

Question 28

what do you get dendritic ulcers in

Answer 28

herpetic keratitis (looks like a branching tree) (caused by herpes simplex)

Question 29

what are the features of herpetic keratitis

Answer 29

dendritic ulcer very painful recurrent (can cause reduced corneal senation, scarring)

Question 30

can you treat herpetic keratitis with steroid

Answer 30

NO can cause corneal to melt and perforate

Question 31

what are the features of adenovirus keratitis

Answer 31

supepithelial infiltrates, almost always with conjunctivitis, bilateral, usually follow URTI, contagious, may affect vision

Question 32

what is the treatment for adenoviral keratitis

Answer 32

topical AB to prevent secondary infection, can give mild steroids to speed up recovery if it becomes chronic

Question 33

what can cause fungal keratitis

Answer 33

acanthamoeba, pseudomonas aeruginosa

Question 34

what is the usual presentation of fungal keratitis

Answer 34

infection caused by contact lenses or in farmers or gardeners after trauma, painful, scarring, very hard to treat, takes long time to heal

Question 35

what is the presentation of orbital cellulitis

Answer 35

``` painful- especially on eye movement proptosis often with paranasal sinusitis pyrexial sight threatening ```

Question 36

what is the risk with orbital cellulitis

Answer 36

compartment syndrome due to pus behind eye, can compromise eye circulation

Question 37

what can cause orbital cellulitis

Answer 37

extension from focal orbital infection, post operative

Question 38

what is the most worrying type of orbital cellulitis

Answer 38

orbital preseptal cant cause compartment syndrome

Question 39

what organisms cause cause orbital cellulitis

Answer 39

staph, strep, coliforms, h. influenzae (children), anaerobes

Question 40

when do you CT scan in orbital cellulitis

Answer 40

if there is any suggestion of muscles or optic nerve dysfunction

Question 41

how do you treat orbital cellulitis

Answer 41

broad spectrum AB, monitor closely, maybe need drainage

Question 42

what is first to go when optic nerve is compromised

Answer 42

colour vision- red

Question 43

what is endophthalmitis

Answer 43

devasting infection inside of the eye, very rare

Question 44

what causes endophthalmitis

Answer 44

post surgical, endogenous (e.g. bacterial endocarditis) often conjunctival commensals- staph epidermis

Question 45

what is the presentation of endophthalmitis

Answer 45

very painful, decreasing vision, sight threatening

Question 46

what is the treatment for endophthalmitis

Answer 46

Intravitreal amikacin/ ceftazidime/ vancomycin and topical antibiotics inject AB after surgery as prophylaxis

Question 47

what is chorioretinitis

Answer 47

infection of the choroid

Question 48

what are the causes of chorioretinitis

Answer 48

``` CMV in AIDS toxoplasma gondii (protozoan) toxocara canis (worm) ```

Question 49

where do you get toxoplasma gondii

Answer 49

cats and raw meat

Question 50

what is the presentation of toxoplasma gondii chorioretinitis

Answer 50

Mild flu like illness Rarely causes any further problems In immunocompetent patients it enters latent phase with cysts forming can reactivate, needs systemic treatment if life threatening

Question 51

where is Toxocara canis (worm) found

Answer 51

cats and dogs | unable to replicate in humans so self limiting

Question 52

is Toxocara canis (worm) choriorentinitis bad

Answer 52

self limiting but can form granulomas which can cause irreversible visual loss

Question 53

when do you do a corneal scrape

Answer 53

in baterial keratitis (bacterial ulcer)

Question 54

how do you diagnose endophthalmitis

Answer 54

aqueous/ vitreous for culture

Question 55

how do you diagnose acanthamoeba

Answer 55

microscopy/ culture

Question 56

when do you serology

Answer 56

if suspect toxoplasma or toxocara (choriodrentinitis)

Question 57

how can you give chloramphenicol

Answer 57

drops (4x per day, has to be kept in fridge) or ointment (had to use)

Question 58

how does chloramphenicol work

Answer 58

Inhibits peptidyl transferase enzyme (therefore stops bacterial protein being made)

Question 59

what does chloramphenicol work against

Answer 59

Bacterocidal for strep and haemophilus | Bacterostatic for staph

Question 60

what are the side affects of chloramphenicol

Answer 60

allergy, aplastic anaemia, grey baby syndrome (when give too much to babies they go grey, reduce dsose)

Question 61

what are antibiotics than inhibit cell wall synthesis

Answer 61

Penicillins & cephalosporins (have B lactam ring)

Question 62

what is dacrocystitis

Answer 62

when lacrimal sac becomes infected

Question 63

what are antibiotics that inhibit nucleic acid synthesis

Answer 63

Quinolones

Question 64

what antibiotic for corneal ulcers

Answer 64

quinolones

Question 65

what are the antibiotics ffor bacterial conjunctivitis

Answer 65

chloramphenicol (treats most bacteria except Pseudomonas aeruginosa) fusidic acid (treats Staph. aureus) gentamicin (treats most Gram negative bacteria including coliforms, Pseudomonas aeruginosa)

Question 66

what treatment for herpetic ulcers

Answer 66

aciclovir

Question 67

how do you treat chlamydial conjunctivitis

Answer 67

topical oxytetracycline

Question 68

how do you treat bacterial keratitis

Answer 68

A 4-quinolone (Ofloxacin) (treats most Gram negative bacteria including coliforms, Pseudomonas aeruginosa, Haemophilus influenzae. Not active vs. Strep. pneumoniae) Gentamicin and cefuroxime (the combination will treat most Gram positive and Gram negative organisms)