Fungal blood cultures
Fungi represent an emerging group of organisms that are
responsible for BSI with increasing frequency. The growth
requirements for fungi often differ from those for bacteria,
most notably with regard to optimal growth temperature and
media. For example, most yeasts grow best at 37°C, whereas
filamentous fungi often grow best at lower (27–30°C)
temperatures. Most routine manual and automated blood
culture systems are able to support the growth of yeasts such
as Candida spp. However, if suspicion is high for a BSI being
caused by yeast, and routine blood cultures are negative, then
it may be reasonable to consider a request for alternative test
methods that are optimally designed to support the growth of
most yeasts. Moulds, and especially dimorphic fungi, often
grow poorly in typical instrumented blood culture systems.
Furthermore, the recovery of moulds such as Aspergillus spp. is