Fun With Fungi

You know that old adage “you can’t teach an old dog new tricks”? Well, laboratory professionals know that’s wrong—not only do we need to learn new tricks, sometimes we need to learn them in order to help diagnose a patient. In that regard, continuing education sessions—like those at ASCP’s Annual Meeting—can be so helpful to bench technologists. Today, I attended “Team Approach to Diagnosis of Fungal Infections” presented by Dr. Jeannette Guarner, MD, FASCP from Emory University in Atlanta, Georgia. Here are some of the tidbits I learned.

• An easy reminder for dimorphic fungus: “mold in the cold, yeast in the beast.”
• In direct stains of tissue samples, not all broad-based budding yeast 8 to 15 microns are Blastomyces. It could be Candida or even Aspergillus.
• If you’re able, tell the clinician to send to biopsy samples for micro AND pathology—shared specimens tend to introduce error.
• Paracoccidioidomycosis is much more common in males (20:1); current thinking is that estrogen is protective.
• Chrysosporium (previously Emmonsia): dimorphic yeast currently only seen in South Africa.
• Fusarium can grow in blood cultures. (In the tissue, it almost looked like Aspergillus with hyaline septated hyphae.)
• Fusarium is generally resistant to antifungals
• When seen in tissue samples, hyaline septated hyphae DOES NOT ALWAYS equal Aspergillus.
• Black molds are black because of melanin, which protects them from UV rays, heavy metals, free radicals, and high temperatures.
• Cryptococcus is the only fungus that has mucin in its cell wall; mucin stain will be positive.
• Crypto can sometimes do a broad-based budding.

-Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.