Fusarium spp. is an emerging fungal pathogen. Although long recognized as a cause of local infection involving nails, traumatized skin, or the cornea (eg, in contact lens wearers), deep or disseminated infection was not described until the mid 1970s. Despite its worldwide distribution and its frequent recovery from soil and vegetative material, infection is quite rare. Only ~ 100 cases involving invasive disease in immunosuppressed patients have been described in the medical literature.
Chromomycosis, also known as chromoblastomycosis, is a chronic subcutaneous infection caused by several different fungi. Although rarely seen in the United States, it is common worldwide. Chromomycosis occurs worldwide but is most frequently encountered in tropical and subtropical regions. The most common occurrence is in barefoot individuals, particularly among agricultural workers.
Paracoccidioidomycosis is caused by Paracoccidioides brasiliensis. Also known as South American blastomycosis, it is the most prevalent systemic mycosis found in Central and South America and is the most common endemic mycosis in this area. Paracoccidioidomycosis is acquired only in Central and South America and ranges from Mexico to Argentina.
Penicillium spp. are ubiquitous in nature and may be recovered with ease from a variety of sources within the hospital environment. These molds commonly contaminate clinical specimens and cause contamination in the laboratory. Colonization of nonsterile anatomical sites in humans is common. In most cases where Penicillium spp. are recovered from clinical specimens, they represent colonization.
Sporothrix schenckii, the causative agent of sporotrichosis, is a ubiquitous fungus commonly found in the soil, on sphagnum moss, on decaying wood, and on a variety of other vegetation. It is found worldwide but prefers a temperate or tropical climate with high humidity.
Aspergillus spp. are found worldwide and grow in a variety of conditions. They commonly grow in soil and moist locations and are among the most common molds encountered on spoiled food and decaying vegetation, in compost piles, and in stored hay and grain. Aspergillus spp. often grow in houseplant soil, and such soil may be a source of Aspergillus conidia or spores in the home, office, or hospital setting. The airborne conidia are extremely heat resistant and can withstand extreme environmental conditions.
Rhinocerebral mucormycosis occurs most commonly in patients with uncontrolled diabetes, especially after an episode of diabetic ketoacidosis. It may also occur in leukemic patients who have had prolonged neutropenia and therapy with broad-spectrum antibiotics and occasionally in organ transplant recipients. The earliest symptoms in rhinocerebral mucormycosis are facial pain, headache, and nasal stuffiness.
P boydii is a mold that is capable of causing infection in immunosuppressed patients and less frequently in immunocompetent patients. Overall, infection with P boydii is rare.
Aspergillus spp. are capable of causing a variety of infections involving the paranasal sinuses (Table 2). Although uncommon, Aspergillus sinusitis is related to the immune status and immunologic response of the host. In the severely immunosuppressed or neutropenic patient, Aspergillus sinusitis or rhinosinusitis may occur. Symptoms include headache, toothache, nasal congestion, purulent nasal discharge, and sinus or eye pain.
Farmer’s lung, also known as extrinsic allergic alveolitis or hypersensitivity pneumonitis, is an allergic inflammatory reaction induced by inhalation of Aspergillus spores, often in exposure to mold and hay. It usually occurs after inhalation during an overwhelming exposure to spores. A multitude of other antigenic stimuli can induce a similar syndrome.