- Systemic mycoses can be caused by pathogenic fungi and include histoplasmosis, coccidioidomycosis, cryptococcosis, blastomycosis, paracoccidioidomycosis, and sporotrichosis, or infections by opportunistic fungi such as Candida albicans, Aspergillus species, Trichosporon, Candida glabrata, Fusarium, Alternaria, and Mucor.
- The diagnosis of fungal infection generally is accomplished by careful evaluation of clinical symptoms, results of serologic tests, and histopathologic examination and culture of clinical specimens.
- Histoplasmosis is caused by Histoplasma capsulatum and is endemic in parts of the central United States along the Ohio and Mississippi River valleys. Although most patients experience asymptomatic infection, some can experience chronic, disseminated disease.
- Asymptomatic patients with histoplasmosis are not treated, although patients who do not have acquired immune deficiency syndrome (AIDS) patients with evident disease are treated with either oral ketoconazole or IV amphotericin B; AIDS patients are treated with amphotericin B and then receive lifelong suppression.
- Blastomycosis is caused by Blastomyces dermatitidis. In the immunocompetent host, acute pulmonary blastomycosis can be mild and self-limited and may not require treatment. However, consideration should be given to treating all infected individuals to prevent extrapulmonary dissemination. All persons with moderate to severe pneumonia, disseminated infection, or those who are immunocompromised require antifungal therapy.
- Coccidioidomycosis is caused by Coccidioides immitis and is endemic in some parts of the southwestern United States. It can cause nonspecific symptoms, acute pneumonia, or chronic pulmonary or disseminated disease. Primary pulmonary disease (unless severe) frequently is not treated, whereas extrapulmonary disease is treated with amphotericin B, and meningitis is treated with fluconazole.
- Cryptococcosis is caused by Cryptococcus neoformans, which occurs primarily in immunocompromised patients, and Cryptococcus gattii, which occurs primarily in nonimmunocompromised patients. Patients with acute meningitis are treated with amphotericin B with flucytosine. Patients infected with human immunodeficiency virus (HIV) often require long-term suppressive therapy with fluconazole or itraconazole.
- A variety of Candida species (including C. albicans, C. glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei) can cause diseases such as mucocutaneous, oral, esophageal, vaginal, and hematogenous candidiasis, as well as candiduria. Candidemia can be treated with a variety of antifungal agents; the optimal choice depends on previous patient exposure to antifungal agents, potential drug interactions and toxicities of each agent, and local epidemiology of intensive care unit (ICU) or hematology–oncology centers.
- Aspergillosis can be caused by a variety of Aspergillus species that can cause superficial infections, pneumonia, allergic bronchopulmonary aspergillosis (BPA), or invasive infection. Voriconazole has emerged as the drug of choice of most clinicians for primary therapy of most patients with invasive aspergillosis (IA). Combination therapy, while widely used, lacks clinical trial data to support its use.
On completion of the chapter, the reader will be able to:
Describe the difference between yeasts and molds.
Define yeast, mold, hyphae, mycelium, septate, and dimorphic fungi.
Describe the difference between primary (intrinsic) resistance and secondary (acquired) resistance.
List the antifungal agents for which clinical breakpoints (CBPs) for Candida species have ...