Mycobacterium – Superficial Abscess, lesion, wound or Aspirate

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Mycobacterium

Abscess contents

≥5.0 ml abscess/wound fluids

Tuberculosis Kit order#: 390042

Mycobacterium

Aspirate

≥5.0 ml abscess/wound fluids

Tuberculosis Kit order#: 390042

Mycobacterium

Biopsy

1.0 gram of tissue

Tuberculosis Kit order#: 390042

Mycobacterium

Wound

≥5.0 ml abscess/wound fluids

Tuberculosis Kit order#: 390042

Mycobacterium

Skin lesion

1.0 gram of tissue

Tuberculosis Kit order#: 390042

Submission and Collection Notes

1

Use the Tuberculosis kit to submit specimens collected aseptically. Specimens in formalin or ANAEROBIC TRANSPORT MEDIUM will not be tested.

2

Indicate if specimen is from a superficial site and the source of the specimen on the General Test Requisition Form. This will prompt the lab to provide the appropriate culture media to support the growth of the Mycobacterium species that prefer to grow at lower temperatures.

3

Indicate if infection was acquired in Africa, Australia, Mexico, South America, Indonesia, New Guinea, or Malaysia, on the General Test Requisition Form, because Mycobacterium ulcerans may require prolonged incubation for primary isolation.If collecting Abscess contents/ Aspirates/Skin lesions, do not use gauze. Small volumes may be submitted in a syringe with needle removed and Luer Lock cap in place.

4

If collecting Cutaneous ulcer specimens, collect the biopsy sample from periphery of lesion, or aspirate material from under margin of lesion.

5

If collecting Tissue, use aseptic technique, select caseous portion if available. Do not wrap in gauze or freeze.

6

Refer to Additional Mycobacterium Collection Information for detailed collection instructions.

Limitations

Swabs are not recommended for the isolation of mycobacteria since they provide limited material and the bacteria adsorb onto the swab material which may contain toxic substances. Negative results obtained from specimens submitted on swabs are not reliable.

Frozen specimens may decrease the yield of mycobacteria.

Specimens obtained for initial diagnosis after the initiation of antimicrobial therapy may produce false negative results.

Saprophytic mycobacteria in tap water may produce false-positive culture or slide results.

Delayed transportation of specimens may promote overgrowth by contaminating indigenous microbiota.

Preparation Prior to Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Place specimen container in the biohazard bag and seal bag, and insert the completed requisition in the pocket on the outside of the sealed biohazard bag.

Special Instructions

Store at 2-8 °C if transport is delayed more than one hour. Specimens should be transferred to the lab ASAP.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Mycobacterial cultures are performed daily Monday to Saturday. 

Turnaround time is up to 1 day from receipt by PHO laboratory for smear results from the concentrated specimen.

Turnaround time for negative cultures is 49 days from receipt by PHO laboratory.

A positive culture is reported within 24 hours of growth. Depending on the species and treatment of the patient, a culture may grow within 1 to 2 weeks or take as long as 6-7 weeks.

All new isolates of M. tuberculosis complex are phoned to the submitter within 24 hours of identification.

STAT and Critical Samples Testing

STAT testing is not available.

Contact Public Health Ontario Laboratory to request approval for URGENT testing. 

If URGENT testing is approved, mark URGENT on the outside of the package as well as on the requisition. A phone number and contact person must be provided for phoning the result.

URGENT Smears Specimens that are received in the lab by 2:00 p.m. will have a smear done and phoned the same day. Specimens that arrive after 2 p.m. will have the smear result phoned first thing the following morning.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Specimens that have smear positive for Acid Fast Bacilli are to be reported to the Medical Officer of Health as per Health Protection and Promotion Act.

Specimens that are positive for Mycobacterium tuberculosis are to be reported to the Medical Officer of Health as per Health Protection and Promotion Act.

Test Methods

A smear, prepared from the concentrate, is stained using the Auramine-Rhodamine (AR) fluorochrome stain and fluorescence microscopy.

A negative AFB smear does not rule out TB, the culture may still be positive.

Specimens are set up for culture on solid and in liquid media and incubated for up to 7 weeks.

contact lab

Contact Laboratory Customer Service

Laboratory Services

customerservicecentre@oahpp.ca

Updated 28 March 2019