Transcript Conjunctival discharge culture

CONJUCTIVAL DISCHARGE
D. M. M. Lab.
Conjunctival Discharge
Aim of the test
An etiological diagnosis of bacterial conjunctivitis by aerobic
cultivation with identification and susceptibility test of the
isolated bacteria.
Types of specimen
Two swabs from discharge from the eye(s).
Criteria of specimen rejection
Inappropriate specimen transport device; mislabeled
specimen; unlabeled specimen; specimen received after
prolonged delay (usually more than two hour); specimen
received in expired transport media.
Common pathogens
Commensals flora
Streptococcus pyogenes
Staphylococcus epidermidis
Pseudomonas aeruginosa
Lactobacillus spp
Chlamydia trachomatis
Propionibacterium spp
Streptococcus pneumoniae
Staphylococcus aureus
Haemophilus influenzae
Various Enterobacteriaceae
Haemophilus aegypticus
Various streptococcus spp
Staphylococcus aureus
Occasion pseudomonas aeruginosa
Neisseria gonorrheae
Streptococcus pyogenes
Pre specimen processing
Who is authorized to order the test
Physician.
Quantity of specimen
Sufficient amount on swab.
Time relapse before processing the sample
Eye specimen should be processed immediately because tears
contains lysosomes which may kill the organism.
Storage
Refrigerated (2-8) 0C .
Pre specimen processing
Conjunctival discharge Specimen collection
I.
Pull down the lower eyelid so that the lower conjunctival fornix
is exposed.
II. Swab the fornix without touching the rim of the eyelid with the
sterile cotton swab.
III. Place the swab immediately in a bacterial transport medium
or, if the specimen is brought to the laboratory immediately, in
a sterile test tube with 0.5 mL of phosphate buffered saline.
Conjunctival discharge Specimen collection
Specimen processing for conjunctiva
Specimen processing for conjunctiva
Direct Visual Examination
All material submitted for culture should always be smeared
and examined directly by gram stain or other appropriate
techniques.
Specimen in which chlamydia is suspected can be stained
immediately with monoclonal antibody conjugated to
fluorescein for detection of elementary bodies or inclusions.
Culture
Because the constant washing action of the tears the number
of organisms recovered from cultures of certain eye infection
may be relatively low, so Conjunctival scrapings place directly
onto media yield the best results.
Specimen processing for conjunctiva
One should use blood, MacConkey and chocolate agar
plates, because potential pathogen may present in an eye
without causing infection it maybe very helpful when any one
eye is infected to culture both eyes, If a potential pathogen
grows in cultures of both infected and un infected eye the
organisms may not be causing the infection, now ever if the
organism only grows in culture from the infected eye, it is
most likely the causative.
Non Culture Methods
ELISA and DIFA staining are now available for detection of
Chlamydia trachomatis
Direct Immuno-fluorescence (DIF) Antibody labeling
for
Chlamydia trachomatis
Chlamydia trachomatis
With Giema stain
Giemsa stain of Chlamydia inclusion bodies
(purple "caps" on epithelial cell).
With Iodine stain
Post specimen processing
Interfering factors:
Patient on antibiotic therapy.
Improper sample collection.
Result reporting:
Report Gram stain finding as an initial report.
Report the isolated pathogen and its sensitivity pattern as a final
report.
Turn around time:
Gram stain result should be available half hour after specimen
receipt.
Isolation of a possible pathogen can be expected after 2-3 days.
Negative culture will be reported out 1-2 days after the receipt of
the specimen.