Mycobacterial Primary culture and Microscopy

Patient Preparation

For general aspects of taking samples we recommend that users follow either their local protocols or “The Royal Marsden Manual of Clinical Nursing Procedures”.

Multiple sputum or urine samples (preferably early morning samples) over 3 consecutive days, or other respiratory or sterile site samples in a sterile universal container (not thin (10ml) urine tubes).

If blood cultures for M.tuberculosis / MAI are required, please telephone the TB laboratory to request TB blood culture bottle(s). TB blood cultures received in routine MC&S blood culture bottles cannot be tested.

 Sputum

• Ask patient to take three deep breaths in through their nose, exhale through pursed lips and then force a deep cough.
• Ask patient to expectorate into a 20ml white top sterile sample container.

Bronchoalveolar Lavage (BAL)

• BAL should be collected according to local protocols using sterile fluids as the instillate.
• Recovered lavage fluid should be aseptically transferred to a 20ml white top sterile sample container

Faeces sample collection

Instructions for patient self-collection of faeces sample:   

How should I collect and store a poo (stool) sample? - NHS (www.nhs.uk)

Instructions for faeces sample collection in hospital:

• Ask patient to defaecate into a clinically clean bedpan or receiver.
• If the patient has been incontinent: a sample may be obtained from bedlinen or pads: try to avoid contamination with urine.
• Using the integrated ‘spoon’ in the sample pot lid, scoop enough faecal material to fill a third of the specimen container (or 10–15 mL of liquid stool).
• Apply specimen container lid securely. 
• Label sample and complete microbiology request form (including relevant information such as onset and duration of diarrhoea, fever or recent foreign travel).
• Dispatch sample to the laboratory as soon as possible or refrigerate at 4–8°C and dispatch within 12 hours.

Nasopharyngeal wash: vacuum-assisted (trap) aspirate method

• Nasopharyngeal wash should be collected according to local protocols using sterile fluids as the instillate.
• Recovered mucus/fluid should sent in a 20ml white top sterile sample container or other well sealed sterile container.

Urine samples for mycobacterial culture

• Collect three early morning urine specimens (i.e. from the first urination after waking).
• Each specimen is to be collected on a different day.
• Use a clean container to collect sufficient urine to fill a 20ml white top sterile sample container.
• Ensure the bottles are labelled with the day of collection i.e. 1, 2 or 3.

Tissue samples for microbiology

• All tissue samples should be collected aseptically and transferred directly to sterile sample containers with no additives of any kind.

Joint aspirates

• All aspirate samples should be collected aseptically and transferred directly to sterile sample containers with no additives of any kind.

Fluid and Pus Samples

• All fluid and pus samples should be collected aseptically and transferred directly to sterile sample containers with no additives of any kind.

CSF samples for microbiology/virology

• Collect specimens preferably before antimicrobial therapy is started, but this must not be delayed unnecessarily pending lumbar puncture and CSF culture.
• CSF is normally collected sequentially into three or more separate containers which should be clearly numbered consecutively on the sample pots (i.e. 1, 2 and 3).
• In adults, we recommend sending samples 1 and 3 for microbiology and sample 2 for biochemistry (protein).
• Ideally a minimum volume of 1mL is needed for each tube but when sample volume is below this it is possible to pool samples.
• For culture for Mycobacterium species (including TB), at least 10mL is preferred where possible as the larger the volume, the greater the culture yield.