1. Ear culture
D. M. M. Lab.

2. Ear Culture Aim of the test Types of specimen
Etiological diagnosis of otitis externa or otitis media by aerobic and anaerobic culture with identification and susceptibility test of the isolated organism(s).
Types of specimen
Two swabs from the external or aspiration from middle ear(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.

3. are present in the external ear canal
common pathogens
Commensals flora
are present in the external ear canal
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes
Lactobacillus spp.
Pseudomonas aeruginosa
Propionibacterium spp.
Other Gram negative bacilli
Streptococcus pneumoniae
Various Enterobacteriaceae
Haemophilus influenzae
Various streptococcus spp
Anaerobic bacteria
Candida spp. other than albicans
Proteus spp.
Occasion Pseudomonas aeruginosa

4. Pre specimen processing
Who will collect the specimen
Medical technologist, Microbiologist for swab from external ear.
Otolaryngologist for aspiration from middle ear.
Who is authorized to order the test
Physician.
Time relapse before processing the sample
Not more than 2 hours.
Storage
Refrigerated (2-8) 0C .

5. Pre specimen processing
External Ear Specimen collection
Collect a specimen of the discharge on a thin, sterile cotton wool or Dacron swab.
Place the swab in a container with the transport medium, breaking off the swab stick to allow the stopper to be replaced tightly.
Label the specimen and send it to the laboratory.
Phosphate buffered saline

6. External Ear Specimen collection

7. Specimen processing for Otitis externa

8. Specimen processing for Otitis media

9. Specimen processing
Ear specimen submitted for culture should be inoculated to blood agar, MacConkey, and chocolate agar plates, anaerobic culture also should be setup on those specimens obtained by tympanocentesis or those obtained from patients with chronic otitis media, or mastoiditis.
Direct visual examination for material aspirated from the middle ear or mastoid is also examined directly for bacteria or fungi.
Cultures from mastoid are generally taken on swabs during surgery and should be transported anaerobically.

10. Additional information
For external ear infections only Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Vibrio spp. and Aspergillus will be looked for and reported.
For middle ear infections only pneumococcus, Streptococcus pyogenes, Haemophilus influenzae and Staphylococcus aureus will be reported with a susceptibility test.
For the chronic discharging ear, Bacteroides species and fungi will also be reported in addition to the organisms reported for middle ear infections.

11. 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 2-4 days.
Negative culture will be reported out 1-2 days after the receipt of the specimen.