Microbiology Flashcards
gram positive can be broken into what?
cocci and bacilli
gram negative can be broken into what?
cocci
cocci-bacilli
bacilli
name the 4 types of ‘itis’ in the eye
conjunctiva = conjunctivitis
cornea = keratitis
entire globe = endophthalmitis
skin/lymph = cellulitis
what 3 things can cause conjunctivitis?
bacteria
virus
chlamydia
Staph aureus, Neisseria gonorrhoeae and Chlamydia trachomatis all cause bacterial conjunctivitis in which age group?
neonates
what 3 common pathogens cause bacterial conjunctivitis in other ages of patients?
staph aureus
strep pneumoniae
haemophilus influenzae (kids)
bacterial conjunctivitis treatment:
swab
chloramphenical qds
when should you avoid chloramphenicol?
history of aplastic anaemia or allergy
what 3 viruses cause viral conjunctivitis?
adenovirus
herpes simplex
herpes zoster
name the self limiting, contagious conjunctivitis that results in a watery eye?
adenoviral conjunctivitis
which viral conjunctivitis is common in the young with milk spots around the eye?
herpes simplex viral conjunctiviits
herpes zoster if on the nose is affecting which nerve?
naso-ciliary nerve
suspect this in bilateral conjunctivitis in young adults unresponsive to treatments…
chlamydial conjunctivitis
what is seen in chlamydial conjunctivitis on the subtarsal?
follicles and sub tarsal scarring
what 3 things cause microbial keratitis?
bacteria
viruses
fungi
what is often seen in bacterial keratitis that is white at the bottom of the cornea?
hypopyon
bacterial keratitis treatment
admission for hourly drops
what 2 viruses can cause microbial keratitis?
herpes or adenovirus
what is the hallmark of herpetic keratitis?
dendritic ulcer
what do you not treat dendritic ulcers in herpetic keratitis with?
STEROIDS!
cause corneal melt
is herpetic keratitis painful?
yes - very
subepithelial infiltrates are seen in which type of keratitis?
adenoviral keratitis
adenoviral keratitis normally follows what?
URTI
adenoviral keratitis is contagious and is unilateral
true or false?
false
adenoviral keratitis is contagious and is BILATERAL
name the 2 fungi causing keratitis
acanthamoeba and pseudomonas aeruginosa
acanthamoeba is classically seen in patients with what?
contact lenses
painful on eye movements proptosis associated with paranasal sinusitis pyrexial sight threatening ENT CT scan to identify orbital abscesses
diagnosis?
orbital cellulitis
orbital cellulitis treatment?
broad spectrum antibiotic
abscess requires drainage
rare red eye sight and life threatening very painful infection inside of the eye
diagnosis?
endophthalmitis
name the organisms that cause endophthalmitis
commensals - staph epidermidis
name the treatment for endophthalmitis
Intravitreal amikacin/ceftazidime/vancomycin and topical antibiotics
inflammation of the choroid and retina that is very very very rare
diagnosis?
chorioretinitis
what 3 things can cause chorioretinitis?
CMV in AIDS
toxoplasma gondii
toxocara canis (worm)
protozoan infection from cats and raw meat
mild flu like illness but can cause cysts in immunocompetent patients
diagnosis?
toxoplasmosis
parasitic nematode - roundworm
affects cats and dogs
self limiting
form granulomas which can cause irreversible visual loss
diagnosis?
toxocara
how do you diagnose bacterial keratitis?
corneal scrape
how do you diagnose endophthalmitis?
aqueous/vitreous for culture
how do you diagnose acanthamoeba?
microscopy/culture
how do you diagnose toxoplasma and toxocara?
serology
how do you diagnose bacterial, chlamydial and viral conjunctivitis?
swab
outline the 3 ways that antibiotics work
- inhibit protein synthesis
- inhibit cell wall synthesis
- inhibit nucleic acid synthesis
name the most commonly used topical antibiotic
chloramphenicol
name the 2 and 1 organisms that chloramphenicol is both bactericidal and becterostatic for respectively
bactericidal - strep and haemophilus
bacteriostatic - staph
what enzyme does chloramphenicol inhibit?
peptide transferase enzyme
what are the 3 side effects of chloramphenicol
allergy
irreversibel aplastic anaemia
grey baby syndrome
name the 2 antibiotics that inhibit cell wall synthesis
penicillins and cephalosporins - have common B lactam ring
an infecting lacrimal sac leading to tears collecting and become stagnant and infected is called what?
dacrocystitis
name the antibiotic that inhibits nucleic acid synthesis
quinolone - ofloxacin
chloramphenicol treats most bacteria except what?
pseudomonas aeruginosa
what does fusidic acid treat?
staph. aureus
what antibiotic treats gram negative bacteria?
gentamicin
name the antiviral that inhibits viral DNA synthesis and is used for dendritic ulcers of the cornea
aciclovir
what is topical oxytetracycline used for?
chlamydial conjunctivitis
in bacterial keratitis, name the antibiotic that treats most Gram negative bacteria including coliforms, Pseudomonas aeruginosa, Haemophilus influenzae. Not active vs. Strep. pneumoniae
a 4-quinolone such as ofloxacin
in bacterial keratitis, name the antibiotic combination that will treat most Gram positive and Gram negative organisms
gentamicina and cefuroxime
