Conjunctival Discharge

Test for Bacterial conjunctivitis

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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

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 pathogen

  • Streptococcus pyogenes
  • Pseudomonas aeruginosa
  • Chlamydia trachomatis
  • Staphylococcus aureus
  • Neisseria gonorrheae
  • Haemophilus influenza
  • Haemophilus aegyptius
  • Streptococcus pneumonia
  • Acremonium curvularia

Commensals Bacteria

  • Occasion pseudomonas aeruginosa
  • Various streptococcus spp
  • Various Enterobacteriaceae
  • Staphylococcus aureus
  • Propionibacterium spp
  • Lactobacillus spp
  • Staphylococcus epidermidis


Specimen collection

1. Pull down the lower eyelid so that the lower conjunctival fornix is exposed. 2. Swab the fornix without touching the rim of the eyelid with the sterile cotton swab. 3. 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 buffered saline (pH 7).

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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 °C). Media

  • Blood Agar
  • Chocolate Agar
  • MacConkey Agar
  • Fluid Thioglycollate

Result reporting:

Report Gram stain finding as an initial report. Report the isolated pathogen and its sensitivity pattern as a final report.

Turnaround time:

Gram stain results should be available 1 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.

Additional information

All bacteria isolated in fair amounts and not resembling contaminants will be identified and tested for antibiotic susceptibility, including susceptibility to chloramphenicol.

  • If trachoma is suspected, conjunctival scraping should be smeared onto a microscopic slide, air-dried and fixed in absolute methanol. Chlamydia antigen detection systems are available for this purpose.


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