Fungus Culture – Susceptibility Testing

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

*Uncontrolled print copy. Valid only on day of print: 01 May 2024.

Testing Indications

Susceptibility testing for yeast will be performed from sterile-sites; exceptions can be made for isolates from non-sterile sites from patients that are immune compromised or in the ICU (please ensure this information is clearly indicated on the requisition).

Susceptibility testing for filamentous fungi is not routinely performed and must be discussed and approved by the PHO Microbiologist that oversees Mycology.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Fungus susceptibility	General Test Requisition	Pure cultures	N/A	Submit isolates on plain fungal media that supports the growth of the isolate.

Submission and Collection Notes

Include the Identification of the fungus and request susceptibility testing on the General Test Requisition Form.

Requests for susceptibility testing on dimorphic fungi will be rejected.

Clearly indicate if the patient is immune compromised or in the ICU on the General Test Requisition Form. Susceptibility test requests for yeast from non-sterile site will be rejected unless the patient belongs to a high risk group (e.g. immunocompromised, transplant, ICU etc). Contact PHO laboratory for special requests that require approval by a microbiologist.

Storage and 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 in a biohazard bag and seal. Store isolate on fungal media at room temperature or 28°C until submitted. Specimens should be shipped to the laboratory ASAP.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

The Fungus culture susceptibility test is done daily Monday to Friday.

Turn-around time for susceptibility testing of pure culture organisms, after receipt by the PHO – Toronto laboratory is:

Candida spp.: within 5 working days
Cryptococcus neoformans and other yeast: within 7 working days
Aspergillus spp.: within 7 working days

Other filamentous fungi variable turnaround time.

Test Methods

Fungus culture (yeast or mould) must be pure and accompanied by the identification of the isolate.

Fungus cultures are tested for Susceptibility by MIC (modified CLSI broth microdilution method).

Susceptibility testing for Candida species will be performed by broth microdilution assay (Sensititre™ YeastOne™) according to CLSI guidelines. MICs (minimal inhibitory concentration) will be reported with interpretation where available.

Susceptibility test requests for yeast from non-sterile site will be rejected unless the patient belongs to a high risk group (e.g. immunocompromised, transplant, ICU etc). This information must be clearly stated on the requisition. Special requests may be accepted at the discretion of the Microbiologist.

Susceptibility testing for Aspergillus species will be performed by broth microdilution assay on request after approval by the PHO Microbiologist that oversees Mycology. Results will be reported as MICs (or equivalent) without interpretation.