Fungus Culture – Blood/Bone Marrow

Specimen Collection and Handling

Specimen Requirements

Additional Information

Full identification will be performed on isolates from sterile sites. Susceptibility testing will be performed on request. Microbiologist approval is required for non-Candida and non-Aspergillus fungus susceptibility testing.

Most fungal blood stream infections are caused by Candida spp. or other yeast, or yeast like organisms, Cryptococcus neoformans, and less frequently Trichosporon, Geotrichum or Rhodotorula. These organisms are adequately detected within 5-7 days by commercial blood culture systems available in most hospital diagnostic labs.

Malassezia is a yeast that is not optimally detected by automated blood culture systems, and requires special isolation procedures. For suspect Malassezia infections, i.e. central line or parenteral nutrition infections and undiagnosed neonatal sepsis, please note this on the requisition so that special techniques can be applied. 

It should be noted that with the exception of Fusarium species, most filamentous fungi are difficult to grow from the blood despite the fact that infections such as disseminated aspergillosis and zygomycosis are spread via the bloodstream.  When Aspergillus is isolated from the blood, it is more often a contaminant than a true positive.

For the detection of fastidious fungi such as Histoplasma, Blastomyces, and Malassezia species, and for clinical situations in which a disseminated fungal infection is strongly suspected but routine bacterial and fungal cultures are negative, a special request for fungal blood culture using the Isolator system is appropriate.