Walsh & Hoyt: Histoplasma Capsulatum (Histoplasmosis)

Histoplasma capsulatum exists in the soil in the mycelial phase but converts to a yeast phase at the body temperature of mammals: 37C. The mycelial form consists of septate branching hyphae that bear spores at both lateral and terminal positions. The hyphae measure 12 micrometers in width, and the spores range in size from 2 14 micrometers in diameter. Spores of all sizes readily become airborne, and their size is such that they easily reach the small bronchioles or alveoli once inhaled. The resulting infection is called histoplasmosis

Walsh & Hoyt: Trichosporon Beigelii (Trichosporonosis)

This fungus is part of the normal human flora. It often grows in cultures of stool, skin, and urine. Patients with acute leukemia or other hematologic malignancies, patients receiving immunosuppressive agents after organ transplantation, patients who have received prosthetic cardiac valves, and patients with AIDS may acquire disseminated trichosporonosis. The typical patient is an immunosuppressed individual who develops symptoms of a subacute or chronic meningitis with moderate CSF pleocytosis and increased protein. Cultures of the CSF may grow T. beigelii

Walsh & Hoyt: Sporothrix Schenckii (Sporotrichosis)

Sporothrix schenckii is a dimorphic fungus. Its mold form consists of clusters of pyriformconidia measuring 23 micrometers x 26 micrometers formed sympodially from the tips of distally tapering conidiophores, whereas its yeast form consists of cells that may be round, oval, or cigar-shaped and that vary in size from 4 to 6 micrometers in diameter. This fungus has been isolated from soil, living plants, and plant debris. Human disease, called sporotrichosis, most often occurs after contact with thorny plants, such as roses or sphagnum moss, that implant the fungus in the subcutaneous tissue of the host. Outbreaks of sporotrichosis have occurred among miners, nursery workers, and other groups of persons handling contaminated timbers, mulch, moss, hay, or other plant materials. Indeed, the largest recorded epidemic of sporotrichosis in the United States, involving 84 patients in 15 states, was associated with infected Wisconsin-grown sphagnum moss

Aspergillosis, Meningitis, and Thrombosis of the Cavernous Sinus

True fungal mycotic aneurysms typically are large and fusiform in shape, as opposed to the more common smaller, round ‘‘mycotic'' aneurysms related to bacterial endocarditis

Histoplasma Capsulatum (Histoplasmosis)

Histoplasma capsulatum exists in the soil in the mycelial phase but converts to a yeast phase at the body temperature of mammals

Walsh & Hoyt: Imidazoles and Triazoles

Azoles, also called imidazoles, are synthetic organic compounds that are characterized by at least one five-member ring that usually contains two nitrogen molecules (the azole ring). This ring is responsible for the antifungal properties of these substances. The addition of a third nitrogen to the azole ring has created a family of drugs called triazoles. Some of the triazoles have an enhanced antifungal spectrum, better penetration of the CNS, and a less adverse effect upon human sterol metabolism

Walsh & Hoyt: Amphotericin B

Amphotericin B is the mainstay of treatment in almost all systemic fungal infections, particularly those that affect the CNS. It destroys fungi primarily by binding to one or more sterols in their cytoplasmic membrane, thus altering membrane permeability. Almost all systemic mycoses respond to treatment with this drug, either alone or in combination with other drugs. The extent of response is dependent on the underlying health and immunocompetence of the patient, the organismresponsible, and the severity and extent of the infection

Fungi and Mycotic Diseases

Opportunistic fungal infections are common and continue to increase in frequency and severity as a consequence of the use of immunosuppressive therapy after solid-organ transplantation and for a variety of diseases, particularly cancer, and because of the increasing prevalence of the acquired immunodeficiency syndrome (AIDS)

Walsh & Hoyt: Coccidioides Immitis (Coccidioidomycosis)

This organism initially was thought to be a protozoan, and its name derives from the Greek Coccidioides, meaning ""resembling the protozoan Coccidia."" The term immitis, from the Latin, meaning ""not mild,"" refers to the potentially severe nature of the disease produced by the organism

Walsh & Hoyt: Chromomycosis (Chromoblastomycosis) and Cerebral Phaeohypomycosis

Chromomycosis is a chronic cutaneous and subcutaneous fungal infection that occurs throughout the world, particularly in tropical and subtropical regions. A number of fungi may cause this condition, including Cladosporium carrionii, Cladosporium trichoides, Exophiala dermatitidis, Fonsecaea pedrosoi, Fonsecaea compacta, Ochroconis gallopavum, Phialophora verrucosa, Rhinocladiella aquaspersa, and Xylohypha bantiana. These fungi typically reside in soil, rotting wood, and decaying vegetation. Traumatic inoculation of fungi into the skin is the main mode of infection. In affected tissue and exudate, all species produce the same type of dark brown cells that are septate and occur singly or in clusters called sclerotic bodies. In culture, all species formheaped-up, dark colonies with short hyphae. They are thus often called ""dematiaceous fungi."