Fungi: It's Not Just Athlete's Foot

With all those scary microbes out there, it's hard to get worked up over a toenail fungus or a case of athlete's foot. But the fungi that cause these and dozens of other infections are not as trivial as they may seem. Fungi have a way of turning nasty--seeping into the bloodstream and invading vital organs. Lately they've been doing that more and more, thanks to increased travel (which exposes people to fungi for which they have no immunity) and to immunosuppressant drugs (which leave patients vulnerable to what would otherwise be innocuous fungal infections). "The kind of thing that used to grow on bread in the kitchen is now causing life-threatening illness," says Dr. Mitchell Cohen, head of fungal and bacterial diseases at the U.S. Centers for Disease Control and Prevention.

At last the lowly fungus is starting to get some respect--and attention from pharmaceutical companies, some of which have launched major new research campaigns to fight the organisms.

However, as anyone who has wrestled with a persistent case of athlete's foot knows, it's not easy to root out a fungus once it's taken hold. Part of the problem is that fungi are complex organisms that have more in common with human cells than with bacteria or viruses; medications that are toxic to fungi are often just as toxic to humans.

So how do you kill a fungus without harming its host? Researchers are pursuing a variety of novel approaches. One Florida-based outfit, the Harbor Branch Oceanographic Institution, is searching for antifungal compounds in a coral-encrusted black sponge found in the Indian Ocean. Merck is expected to get FDA approval this year for a novel class of antifungals derived from Spanish soil.

But the real hopes for the long term are pinned to molecular biologists; they are best equipped to identify targets unique to fungi and to design drugs that will attack them and them alone. Tiny biotech companies and huge pharmaceutical firms alike are working on drugs that will kill off fungi by preventing enzymes from binding to DNA or by halting protein synthesis.

The good news about fungi is that they are relatively stable. As recalcitrant as they are, they don't morph rapidly like bacteria into superstrains that are resistant to drug therapy. So once someone figures out how to control fungi, chances are they will remain at bay for a long time.

--By Janice M. Horowitz