CONJUCTIVAL DISCHARGE

D. M. M. Lab.

Conjunctival DischargeAim 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 rejectionInappropriate 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 gonorrheaeStreptococcus

pyogenes

Pre specimen processing

Who is authorized to order the testPhysician.

Quantity of specimenSufficient amount on swab.

Time relapse before processing the sampleEye specimen should be processed immediately because tears

contains lysosomes which may kill the organism.

StorageRefrigerated (2-8) 0C .

Pre specimen processing

Conjunctival discharge Specimen collectionI.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 ExaminationAll 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.

CultureBecause 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 MethodsELISA and DIFA staining are now available for detection of Chlamydia trachomatis

Direct Immuno-fluorescence (DIF) Antibody labeling for

Chlamydia trachomatis

With Iodine stainWith Giema stain

Chlamydia trachomatis

Giemsa stain of Chlamydia inclusion bodies (purple "caps" on epithelial cell).

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.

EAR CULTURE

D. M. M. Lab.

Ear Culture

Aim of the testEtiological 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 rejectionInappropriate 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 floraare present in the external ear canal

Staphylococcus aureus

Staphylococcus epidermidis

Streptococcus pyogenes

Lactobacillus spp.

Pseudomonas aeruginosa

Propionibacterium spp.

Other Gram negative bacilli

Staphylococcus aureus

Streptococcus pneumoniae

Various Enterobacteriaceae

Haemophilus influenzae

Various streptococcus spp

Anaerobic bacteriaCandida spp. other than albicans

Proteus spp.Occasion Pseudomonas aeruginosa

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 testPhysician.

Time relapse before processing the sample Not more than 2 hours.

StorageRefrigerated (2-8) 0C .

Pre specimen processing

External Ear Specimen collection1.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.