Microbiology Flashcards
what colour is gram +ve and -ve stain?
gram +ve purple
gram -ve pink
what is the term used for infection of the cornea?
keratitis
what is the term used for infection of the entire globe?
endophthalmitis
in addition to infetion of the corne and the globe what are two other eye infections ?
conjuctivits
cellulitis
bacterial conjuctivitus is watery/lots of pus
bacterial = pus
viral = watery
what are 3 causitive organisms of bacterial conjuctivitus in neonates?
S aureus
Neisseria gonorrhoeae
Chlamydia trachomatis
name 3 causitive organisms of bacterial conjuctivitis in all ages?
S aureus
Sterp pneumoniae
Haemophilus influenzae
how is bacterial conjuctivitus treated?
swab
topical antibitotic
drop vs ointment
what topical antibitoic is most commonly used in bacterial conjuctivitis?
chloramphenical qds
when should you avoid chloramphenicol?
history of aplastic anaemia or allergy
name 3 causitive organisms of viral conjuctivits?
Adenovirus
Herpes simplex
Herpes Zoster
what can be seen around the eye in viral conjuctivits caused by herpes simplex?
cold sores
what clinical sign can be seen in viral conjuctivitus caused by herpes zoster?
Hutchisons sign- tip of the nose
how quickly should you aim to treat viral conjuctivitis caused by herpes zoster?
within 72hrs to reduce incidence
conjuctivitus caused by herpes zoster is known as what?
herpes zoster opthalmicus
what kind of conjuctivits has a ‘rice grain’ appearance?
chlamydial conjuctivitus
what is suspect with bilateral conjuctivitus in young adults?
chlamydial conjuctivitus
chlamydial conjuctivitis can cause ______ ______
subtarsal scarring
what is a hypopyon?
exudate in the anterior chamber of the eye
do you require hospital admission for bacterial keratitis?
yes- admitted for hourly drops
what clinical sign is seen in herpetic keratitis?
dendritic ulcer
herpetic keratitis can eventually result in what?
reduced corneal sensation
treating herpetic keratitis with steroids can result in what?
corneal melt and perforation of the cornea
subepithelial infiltrates can be seen in which kind of keratitis?
adenoviral keratitis
list common features of adenoviral keratitis
bilateral
usually follows URTI
contagious
what are two fungal causes of keratitis?
acanthamoeba
pseudomonas aeruginosa
what imaging technique is used to identify orbital abscesses in orbital cellulitis?
CT scan
what condition is this?
orbital cellulitis
orbital cellulitis can occur due to a direct extension from _____
sinus
what do you need to differentiate between in cellulitis?
orbital and preseptal
what are some causitive organisms of orbital cellulitis?
staphylococci
streptococci
coliforms
haemophilus influenzae
anaerobes
when should you scan in orbital cellulitis?
any suggestion of muscle restriction or optic nerve dysfunction
how do you manage orbital cellulitis?
broad spectrum AB and monitor closely
describe endophthalmitis
devastating infection inside of the eye
how can endophthalmitis occur?
usually post surgical
endogenous i.e haematogenous infection spread in immunocompromised patient
what condition is this?
endophthalmitis
very red eye
sight threatening
what is the most common causitive organism of endophthalmitis?
staph epidermis
what is the treatment for endophthalmitis?
ceftazidime
vancomycin
intravitreal amikacin
define chorioetinitis
inflammation of the choroid
what are 3 causes of chorioretinitis?
CMV in aids
toxoplasma gondii
toxocara canis
in which infection is a corneal scrape used for diagnosis?
bacterial keratitis
what is used for diagnosis in acanthamoeba?
microscopy
culture
serology is used for which infections?
toxoplasma
toxocara
what are the three broad categories of antibiotics?
inhibit protein synthesis
inhibit cell wall synthesis
inhibit nucleic acid synthesis
what does chloramphenicol inhibit?
peptidyl transferase enzyme
which category of antibiotic is used for strep and haemophilus?
bacteriocidal
what category of antibiotic is used for staph?
bacteriostatic
what is grey baby syndrome?
side effect of chloramphenicol due to lack of liver enzymes to metabolise the drug
what, common to penicillins and cephlasporins, inhibtis the enzyme responsible for cell wall production?
B lactam ring
which antibiotics inhibit DNA gyrase therefore inhibting nucleic acid synthesis?
quinolones
what is a common contaminant of eye drop bottles?
pseudomonas
what treats s aureus bacterial conjuctivitis?
fusidic acid
gentamicin treats gram -ve/+ve bacteria?
gram -ve,
includingcoliforms and pseudomonas
acliclovir inhibits DNA synthesis true/flase
true
