Mycology lab safety

Biosafety levels

Biosafety risk groups
- RG1: low individual risk and low community risk; e.g. Saccharomyces, Lactobacillus
  - Essentially non-pathogenic microbes
- RG2: moderate individual risk and low community risk; e.g. Listeria, Campylobacter
- RG3: high individual risk and low community risk; e.g. TB, Yersinia pestis, SARS
- RG4: high individual risk and high community risk; e.g. Marburg virus, Ebola virus
Containment levels essentially correspond to the risk groups
- CL1 through CL4
- CL2-Ag for agriculture
- CL2-P for prion
HRLMP has a CL2 microbiology lab at HGH.
Mycology laboratory
- Class II B2 BSCs to eliminate puff-back during failure of ventilation. Ducts 100% HEPA-filtered air to the outside (no exhaust back into the laboratory). Toxic, volatile or radioactive chemicals can be used in this cabinet.
- Examine all culture media in a BSC. All work/subculture must always be done in the BSC.
- Seal all plates with Parafilm for: systemic specimens (respiratory, blood, tissue, body fluid).
- Place all discarded plates into a tied up biological hazard bag before placing in discard bin.

Risk Group 3 fungi:
- Blastomyces dermatitidis
- Cladophialophora spp. including Clado. Bantiana (black mold that causes CNS disease)
- Coccidioides immitis and Cocci. posadasii
- Cryptococcus spp. including Crypto. gattii
- Histoplasma spp. including H. capsulatum var. capsulatum, H. capsulatum var. farciminosum, and H. duboisii
- Loboa loboi
- Paracoccidioides brasiliensis
- Rhinocladiella mackenziei (common cause of human cerebral phaeohyphomycosis)
Additional RG3 precautions:
- Sealed windows
- Use of a BSC for all work with open vessels
- Inward-directional airflow
- HEPA filtration of exhaust air
- Strictly controlled lab access
CL2 laboratory management of RG3 organisms:
- Perform all procedures with an organism that could be RG-3 in a BSC
  - Including all fungal culture media. Only open plates (including bacterial plates) that have a white or grey mold inside the Mycology BSC.
  - If KOH prep suggests dimorphic fungus:
    - Use lab gowns with elasticized wrists, gloves, and an N95 mask while examining plates in the BSC.
    - Place a warning note in LIS.
    - Notify the Manager/Supervisor and Microbiologist if plates grow white mold.
- Notify the Microbiologist and Supervisor if suspect dimorphic fungi based on KOH-Calcofluor or plate growth.
- All specimens are referred to the Toronto Public Health Lab following Transportation of Dangerous Goods regulations.
  - Follow all patient samples that went to other lab benches.

There is a broad range of risk, and it may be difficult to assess. A small dose of arthroconidia may cause disease in humans, and attack rates in lab exposure are generally higher than natural exposure.
Risk increases with the quantity of arthroconidia and the duration of exposure.
Arthroconidia in culture develop after a few days, and reach very large numbers by 7 to 10 days, at which point they may be dispersed by simply opening the plate.

Obtain baseline Coccidioides serology for IgM and IgG to help determine prior exposure. Travel history may also be helpful.
All exposed personnel should be given itraconazole or fluconazole orally (400 mg daily, for adults) for 6 weeks, as prophylaxis.
- If pregnant, avoid azoles, monitor closely, and start amphotericin if she develops infection. Can alternatively prophylax with once-weekly amphotericin for 6 weeks or until the end of pregnancy.
If any exposed personnel develops cough or fever during the 6 week period of prophylaxis, they should be assessed by a physician. Repeat serology may be helpful.
Repeat serology before completion of prophylaxis. If negative, stop prophylaxis; if positive, follow-up closely for up to 1 year.