untitled

of the most significant invasive fungi in deep surgical

procedures, and the survival rate can be as low as

30%. Many other fungi that can grow at 37°C have

spores that are small enough to enter the lungs and

reach the alveoli. These fungi were virtually unknown

until recently but are now extremely common causes

of infection in immunodeficient patients. For example,

the fungus-like organism Pneumocystis jiroveci (previously

named P. carinii) commonly causes pneumonia in

patients infected with the human immunodeficiency

virus (HIV). The onset of this disease in patients

with HIV is regarded as one of the “AIDS-defining”

symptoms.

Only a handful of antifungal drugs are available to

treat the major human mycoses, and most need to be

administered at low doses over a prolonged time to

avoid excessive toxicity. Many of these drugs are

expensive so they offer little hope to the poorest people

in the developing world. Chapter 16 is devoted to

the mycoses of humans, and Chapter 17 deals with the

drugs available to treat these conditions.

Fungal parasites as biological control

agents

Fungi parasitize many types of host, including

other fungi (mycoparasites, Chapter 12), insects

(entomopathogens, Chapter 15), and nematodes

(nematophagous fungi, Chapter 15). In the past,

such fungi might have been regarded as curiosities, but

now they are recognized as being significant popula-

tion regulators of their hosts and as potential biolo-

gical control (biocontrol) agentsof major pests or

plant pathogens. We discuss biocontrol at many

points in this book, notably in Chapters 12 and 17.

Fungal saprotrophs

Saprotrophs (saprophytes) are organisms that feed on

dead organic matter (sapros=death; trophy=feeding).

Fungi play a major role in this respect because they

8 CHAPTER 1

Fig. 1.5A sign in Arches National Park, Utah, USA. Get your boots off our microbes!

FB4eC01 04/12/2005 12:26PM Page 8