Chapter 8.1 : Introduction and General Considerations

Abstract:

Fungi are significant, sometimes overlooked, human pathogens. Infections range in severity from merely cosmetic to life threatening. Over the last decade, in particular, the spectrum of agents responsible for infection has altered in response to changes in the susceptible population, notably, increases in immunocompromised subjects and greater use of antifungal agents. Fortunately, awareness of the role of opportunistic fungi in disease is growing, but with that awareness the clinical laboratory must be prepared to identify a range of fungal species. In addition, new antifungal agents less toxic than amphotericin B and variously administered have increased the requirement to identify potential pathogens to the species level. (It is no longer acceptable in most situations to report a yeast that does not produce germ tubes as “yeast, not Candida albicans.”) While amphotericin B is effective against many invasive fungal pathogens, newer drugs with a narrower spectrum of efficacy are available (e.g., the echinocandins). Resistance to these drugs is sometimes a species characteristic and may also be isolate dependent for other species. This section brings together the contributions of well-respected mycologists, whose expertise should help laboratories become more adept at identifying fungi, recognizing the significance of an isolated organism, and performing susceptibility testing.