Abstract:
Fungi are ubiquitous eukaryotic plant like organisms living in soil and decaying matter.
They are generally classified as either yeasts or molds, although some are also dimorphic,
which exists as yeasts within the host but take the form of mold at room temperature in
vitro. There are more than a million species of fungi but only a minority of them less than
200 are pathogenic. Some mycotic infections are not transmissible amongst humans and
do not require special precautions. However some fungi can be highly infectious if
inhaled. Fungi have emerged as significant pathogens during the past few decades when
they became more and more frequently diagnosed as opportunistic infections in
immunocompromised host.
Fungal infections in humans are known as mycoses and are broadly of three types -
superficial, subcutaneous and systemic mycoses (Friend, 1999; Anantnarayan, 2000).
Superficial infections are by far the common ones and comprise various types of tinea or
ringworm affecting the skin, hair and nails. These are mild though chronic disease.
Subcutaneous mycoses involves the dermis, subcutaneous tissues, muscles, and fascia.
Systemic mycoses occurs in varying degree of severity ranging from asymptomatic
infections to fatal diseases. Oppurtunistic infections occur in patients with debilitating
diseases such as cancer or diabetes or in whom the physiological state has been altered by
immunosuppressive drugs, steroid, X- rays or broad spectrum antibiotics.
The list of documented fungal pathogens is extensive, and one can no longer ignore or
dismiss fungi as contaminants or clinically insignificant when they are isolated from
clinical material. It is also apparent that the prognosis and response to therapy may vary
with the type of fungus causing the infection as well as with the immunological status of
the host. Table 2.1 lists the main groups of mycoses, their etiologic agents, clinical
manifestations and treatment options.
