Pathogenesis and spectrum of disease of the opportunistic Mycoses
المؤلف:
Patricia M. Tille, PhD, MLS(ASCP)
المصدر:
Bailey & Scotts Diagnostic Microbiology
الجزء والصفحة:
13th Edition , p741-742
2025-11-27
50
Aspergillus spp.
Aspergillus spp. are capable of causing disseminated infection, as is seen in immunocompromised patients, but also of causing a wide variety of other types of infections, including a pulmonary or sinus fungus ball, allergic bronchopulmonary aspergillosis, external otomycosis (a fungus ball of the external auditory canal), mycotic keratitis, onychomycosis (infection of the nail and sur rounding tissue), sinusitis, endocarditis, and central nervous system (CNS) infection. Most often, immunocompromised patients acquire a primary pulmonary infection that becomes rapidly progressive and may disseminate to virtually any organ.
Fusarium spp. and Other Hyaline Septate Opportunistic Molds Infection caused by Fusarium spp. and other hyaline septate monomorphic molds is becoming more common, particularly in immunocompromised patients. These organisms are common environmental flora and have long been known to cause mycotic keratitis after traumatic implantation into the cornea. Disseminated fusariosis is commonly accompanied by fungemia, which is detected by routine blood culture systems. In contrast, the aspergilli are rarely recovered from blood culture, even in cases of endovascular infection. Necrotic skin lesions are common with disseminated fusariosis. Other types of infection caused by Fusarium spp. include sinus itis, wound (burn) infection, allergic fungal sinusitis, and endophthalmitis.
Fusarium spp. are commonly recovered from respiratory tract secretions, skin, and other specimens from patients who show no evidence of infection. Interpretation of culture results rests with the clinician and is often assisted by correlation with histopathology results. Geotrichum candidum is an uncommon cause of infection but has been shown to cause wound infections and oral thrush; it is an opportunistic pathogen in the immunocompromised host. Acremonium spp. are also recognized as important pathogens in immunocompromised hosts; these have been associated with disseminated infection, fungemia, subcutaneous lesions, and esophagitis. Penicillium spp. are among the most common organisms recovered by the clinical laboratory. In North America they are rarely associated with invasive fungal disease. However, they may be a cause of allergic bronchopulmonary penicilliosis or chronic allergic sinusitis. One species, P. marneffei, is an important and emerging pathogen in Southeast Asia and is discussed further in the section on dimorphic pathogens. Of the Paecilomyces species, P. lilacinus appears to be the most pathogenic species and has been associated with endophthalmitis, cutaneous infections, and arthritis. P. variotii has also been shown to be an important pathogen, causing endocarditis, fungemia, and invasive disease.
A variety of other saprobic fungi that are not discussed here may be encountered in the clinical laboratory but are seen less commonly. Other references are recommended for further information about identification of these organisms.
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