Mycobacterium – detection – Respiratory

Detection of acid fast bacilli in respiratory specimens
Microbiology
Bacteriology
○ Sputum (5-10mL) ○ Tracheal aspirate ○ BAL (5mL) ○ Bronchial washing (5mL) ○ Esophageal brushing ○ Lung tissue (1-2 g)

Other Information

○ Pooled specimens, saliva, 24h collections, specimens received in formalin, frozen specimens, dry swabs or swabs received in anaerobic transport medium and specimens in endotracheal tubes will not be tested
○ Swabs are not recommended for the isolation of mycobacteria. They are acceptable only if a specimen cannot be obtained by other means.

○ Sterile container for fluids
○ Sterile container with small amount of normal saline for tissues


Sputum/tracheal aspirate
○ Collect sputum by expectoration or by tracheal aspiration in sterile container. Collect 3 sputum specimens (spontaneous or induced) on the same day at least 1 hour apart or optimally, 3 early morning sputum specimens for 3 consecutive days. Do not pool specimens or have the patient rinse mouth with tap water before producing sputum.
○ For endotracheal aspirates, collect aspirated material using a NEW sterile catheter or in-line catheter and aspirate material from the trachea using a syringe or suction device

BAL
○ Pass bronchoscope transnasally or transorally (if patient is not intubated) or via endotracheal tube (if patient is intubated). Instill a large volume of 0.85% sterile saline (nonbacteriostatic) into the airway lumen. Discard the initial fluid recovered (likely contaminated). Collect remaining fluid in a clean, sterile container via suction.

Bronchial washing
○ Pass bronchoscope transnasally or transorally (if patient is not intubated) or via endotracheal tube (if patient is intubated). For washings, inject aliquots of approximately 20 to 30 mL of 0.85% sterile saline (nonbacteriostatic) for adults, or 5 mL for children. Suction washings into a sterile container. Avoid contaminating bronchoscope with tap water as it can produce false positives.

Esophageal brushing
○ Instill brush to collect cellular material from esophageal wall. Place protected brush sample in sterile container with 1 mL of saline.

Tissue (lung)
○ Collect 5-10 mm3 tissue aseptically using surgical technique or aspiration with a fine needle. Place in a clean, sterile container with a small amount of sterile saline. Do not submit tissue samples on gauze.


Refer to section Sample Processing / Delivery

PHOL

○ Microscopy: 1 day
○ Culture: Up to 49 days; a positive culture is reported within 24h of growth

416-586-4800 extension 4569

NO

○ Label specimen container. Place specimens in biohazard bag and seal.

○ Specimens should be stored at refrigeration temperature (2-8˚C) after collection if transport is delayed more than one hour. Transport to the UHN/SH Microbiology Laboratory ASAP after collection.

○ The specimen will be referred to the Public Health Ontario Laboratory for testing.