Question: What fungus causes mycosis fungoides? Answer: None! Mycosis fungoides is the common name for the most common type of cutaneous T-cell lymphoma. A lymphoma is a malignancy of the white blood cells that are known as lymphocytes. Mycosis fungoides primary involves the skin and produces patches, plaques and tumors. The patches may be scaly or flaky and can thus look a lot like an ordinary rash such as the rash of proriasis or of a non-specific dermatitis. Many times, the plaque-like rash will look like a fungal dermatitis, and thus the name for the syndrome. However, there really is […]

Question: Do you know of any research indicating fungal or mould susceptibility to quinine analogues such as chloroquine or plaquenil or the quinolones, like ciprofloxacin? Answer: The antimalarial drug chloroquine has been shown to have in vitro antifungal activity against some fungi including Penicillium marneffei, Histoplasma capsulatum, and Cryptococcus neoformans, but the clinical utility has not been established. The mechanisms of action are also under investigation. Chloroquine inhibits growth of H. capsulatum by pH-dependent iron deprivation, but is directly toxic to C. neoformans, possibly by pH disturbances in acidic vesicles [Weber, Boelart], however, in other fungi, other as yet undefined […]

Question: I see the word for filamentous fungus written as both ‘mold’ and ‘mould’. Which is correct? Answer: See the discussion at the end of the (A):Introduction to The Fungi

Question: I’m confused about this yeast thing. Is Candida yeast the same as Baker’s yeast or Brewer’s yeast? Answer: No, they are completely different. Yeast is a word that describes only the shape of the fungus! There are, however, many different kinds of yeast. When bakers, brewers, and molecular biologists speak of yeast, they are almost always talking about Saccharomyces cerevisiae, the very friendly yeast used in baking and brewing. The manufacturer of (E):Red Star Yeast offers a really nice booklet on this helpful fungus. When doctors and patients talk about yeast infections, they are almost always talking about candidiasis […]

Question: Everyone knows about amphotericin B and the potential side effects. But what happened to amphotericin A? Answer: Amphotericin A didn’t have useful antifungal activity, so during the original manufacturing process of amphotericin B the goal was solely to reduce the amount of amphotericin A below 15% (much lower now).  Toxicity was not improved with reductions in amphotericin A so its unlikely to significant contribute to toxicity either.

Question: With regard to Minimal Inhibitory Concentration (MIC) measurements for fungi, what is generally considered the cutoff between “susceptible” and “resistant?” What do specific numbers actually mean? Answer: MIC values by themselves have no meaning. One must know which organism is being tested and against what drug. For organisms with no defined endpoints (and there are many), one would like to see a drug level concentration above the MIC.Standardized susceptibility testing for selected organism-drug combinations has demonstrated that correlations between MIC and clinical outcome do exist, especially with the Candida species and the azole antifungal agents.For mould, susceptibility testing has […]

Question: What is ringworm? Is there really a worm involved? Answer: No, there is no worm! This is a fungal infection. See Tinea corporis or onychomycosis.

Question: I think I’ve got fungus growing in my building or home. I think it is making (or might make) me sick! What can I do? Answer: See our discussion of (A):Environmental Mycoses.

Question: I recently attended a mycology workshop and several of the participants mentioned ruling out Coccidioides immitis by using media containing cycloheximide. Currently if we have a white spreading mould that will not sporulate, we do a probe to verify Coccidioides or rule it out. Can we screen those using a simpler and cheaper test? Answer: Coccidioides immitis is a thermally dimorphic fungus that is resistant to cycloheximide. Therefore, incorporation of cycloheximide into the growth medium would discourage or inhibit the growth of most moulds, but would still allow Coccidioides spp to grow. Unfortunately, several other fungi, including Blastomyces dermatitidis, Paracoccidioides […]

Question: Can Candida (yeast) in my diet or body really make me tired (or give me asthma, or headaches, or any other symptom you care to name)? Answer: See Chronic Candidiasis.

Question: In our project, we test the antifungal activity of some compounds against fungi as Candida or Malassezia.My question is about the medium. Could you tell me why the NCCLS decided to use RPMI 1640 as the test medium? The problem is I can’t grow the fungi in this medium. And, could you tell me why they propose to use RPMI 1640 lacking sodium bicarbonate? What occurs with sodium bicarbonate? Answer: The NCCLS methods are reference standards, not intended for routine use in clinical laboratory settings. Nonetheless, the procedures set forth in their documents provide a starting place for most […]