Transcript Ear discharge culture

EAR CULTURE
D. M. M. Lab.
Ear Culture
Aim of the test
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.
common pathogens
Commensals flora
are present in the external
ear canal
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes
Lactobacillus spp.
Pseudomonas aeruginosa
Other Gram negative
bacilli
Streptococcus pneumoniae
Propionibacterium spp.
Haemophilus influenzae
Various streptococcus spp
Anaerobic bacteria
Candida spp. other than albicans
Proteus spp.
Occasion Pseudomonas aeruginosa
Staphylococcus aureus
Various Enterobacteriaceae
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 .
Pre specimen processing
External Ear Specimen collection
1. Collect a specimen of the discharge on a thin, sterile cotton
wool or Dacron swab.
2. Place the swab in a container with the transport medium,
breaking off the swab stick to allow the stopper to be replaced
tightly.
3. Label the specimen and send it to the laboratory.
External Ear Specimen collection
Specimen processing for Otitis externa
Specimen processing for Otitis media
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.
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.
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.