Microbiology Flashcards
An infection of the cornea is also know as?
Keratitis
What are the common pathogens in neonatal bacterial conjunctivitis?
S.Aureus
N.Gonorrhoeae
Chlamydia Trachomatis
What should be done with a case of neonatal bacterial conjunctivitis?
All should be referred onto ophthalmology
What are the common pathogen in bacterial conjunctivitis?
S.aureus
Strep Pneumonia
H.Influenza - Children
What is the treatment for bacterial conjunctivitis?
Swab + Topical Antibiotics
What is the most used antibiotic in bacterial conjunctivitis?
Chloramphenical
What other antibiotics can be used in bacterial conjunctivitis?
Gentamicin - Gram -ve and +ve
Fusidic Acid - Staph Aureus
What are the common pathogens in viral conjunctivitis?
Adenovirus
Herpes Simplex
Herpes Zoster
What is the clinical picture of someone with adenovirus conjunctivitis ?
Red irritated sclera, clear lense, no excess exudate
What is the clinical picture of someone with herpes simplex conjunctivitis?
White pustules around the orbit
Red sclera
No excess exudate
What is the clinical picture of someone with herpes zoster conjunctivitis ?
Punched out lesions in dermatomal pattern
What is the disease history in someone with chlamydia conjunctivitis?
Often chronic and unresponsive to treatment.
When should chlamydia conjunctivitis be suspected?
Bilateral conjunctivitis in a young adult
+/- urethritis or vaginitis
What is important to get the patient too do once a diagnosis of chlamydia has been given?
Contact tracing
What is the clinical picture of someone with chlamydia conjunctivitis?
Red irritated sclera
Excess exudate - gunk and tears
Follicles on the conjunctiva underside of the eyelid
Subtarsal scarring
What is the treatment for chlamydia conjunctivitis?
Topical oxytetracyline
Oral azithromycin for the genital infection
What method is used to diagnose and detect the disease causing pathogen in microbial keratitis?
Corneal scrapes
What is the clinical picture in someone with bacterial keratosis?
White blood cell rich exudate within the anterior chamber look for fluid level within the cornea.
Red irritated sclera
Excess exudate
What topical antibiotics can be used in bacterial keratosis?
Gentamicin + Cefuroxime
Gram +ve and -ve
What should be done for someone with bacterial keratosis?
Admission for hourly drops and daily review
What is bacterial keratosis linked to?
Contact lenses
What is the clinical picture in someone with a herpes keratosis?
Very painful - look for ulceration
Irritated sclera
Lack of exudate
What is the treatment plan for herpes keratosis?
Topical antiviral - acyclovir
NEVER use steroids as cause corneal perforation.
Chronic herpes keratosis can cause what within the eye?
Loss of corneal sensation- won’t detect or respond t to damage being done to the eye.
What is the clinical picture of someone with adenovirus keratosis?
Bilateral conjunctivitis
Sub epithelial infiltrates within the anterior compartment.
Red irritated sclera
What usually precedes adenovirus keratosis?
An URTI
What is the added risk of adenovirus keratosis?
It is infectious
What is the treatment for someone with adenovirus keratosis?
Topical antiviral
Topical antibiotic to prevent secondary infection
Chronic infections - steroids can speed the healing
What are the common organisms that cause fungal keratosis?
Pseudomonas Aeruginosa
Acanthamoeba
What is the disease profile of someone with fungal keratosis?
Slow progression but also slow to heal
Linked to trauma from vegetation.
What is the clinical picture of someone with orbital cellulitis?
Excruciating pain on movement of the eye
Proptosis - out bulging go the eye and eyelid
Fever
Systemically unwell
What is an orbital cellulitis linked to?
Paranasal sinusitis
Post operative
Focal Orbital infection
What should be undertaken immediately once orbital cellulitis is suspected?
CT scan to determine whether the optic nerve, artery and vein have been occluded.
What is the treatment for someone with orbital cellulitis?
Broad spectrum antibiotics + Monitor
Severe cases where sight is threatened drainage as a surgical intervention is an emergency.
How is the causative organism identified in endophthalmitis?
Aqueous or vitreous culture.
What is the clinical picture in someone with endophthalmitis?
Very painful Decreasing vision Really irritated and red sclera Massive exudate Yellow misty cornea
What are the main causative organisms in endophthalmitis?
Staph epidermis
Conjunctival commensals
What is the treatment for someone with endophthalmitis?
Intravitreal Amikacin / Ceftazidime / vancomycin
Topical antibiotics
What is chorioretinitis?
Inflammation of the choroid and the retina
If a patient with AIDS presents with chorioretinitis what is the most likely cause?
CMV - Cytomegalovirus
On fundoscopy what does a CMV infection look like?
Fluffy white perivascular lesions
Haemorrhage
Granular retinal necrosis
What is toxoplasma gondii associated with in chorioretinitis?
Raw meat and cats
What is the clinical picture in someone with toxoplasma gondii chorioretintis?
Mild flu
White focal retinitis +Vitreous inflammation
Chronic - cysts
What is toxocara Canis?
Roundworm
What us toxocara Canis linked to?
Dogs and cats
Why do toxocara Canis present a risk despite being self limiting?
They form granulomas
How does chloramphenicol work?
Inhibits peptidyl transferase - stops protein synthesis
Chloramphenicol is bactericidal to which organisms?
Streptococci
Haemophilus
Chloramphenicol is bacterostatic to which organisms?
Staphylococci
What antibiotics inhibit cell wall synthesis?
Penicillins
Cephalosporins
Both have a Beta lactic ring
What antibiotics inhibit nucleic acid synthesis?
Quinilones e.g. Ofloxacin
Inhibit DNA gyrase so DNA unravels
