Brain heart infusion is often used as an enrichment to enhance the primary recovery of dimorphic fungi from clinical materials; however, it also enhances the growth of other fungal species as well. Cycloheximide is an antifungal agent that binds to the 80S ribosome of many eukaryotes and prevents protein synthesis by blocking the transfer of RNA to the growing polypeptide chain. The dimorphic fungi have developed resistance to this antifungal agent and can grow in the culture media to which it has been added, in contrast to most rapidly growing saprophytes.
