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Aspergillosis
1Department of Medical Specialties, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Abstract:
Aspergillus spores are ubiquitous in the environment and may become concentrated in hospital ventilation systems. Colonization in normal hosts can lead to allergic diseases ranging from asthma to allergic bronchopulmonary aspergillosis. Normal hosts rarely develop invasive disease, which is primarily an infection of severely immunocompromised patients. The major predisposing factors for infection include prolonged neutropenia, chronic administration of adrenal corticosteroids, the insertion of prosthetic devices, and tissue damage due to prior infection or trauma. Since Aspergillus spp. are respiratory pathogens, the most common form of infection is pneumonia followed by sinusitis. Patients with preexistant cavitary disease may develop noninvasive aspergillomas. Most infections are caused by Aspergillus fumigatus. The organism is capable of invading across all natural barriers, including cartilage and bone. It has a propensity for invading blood vessels causing thrombosis and infarction. The diagnosis of pulmonary infection is usually difficult to establish because the organism is seldom cultured from sputum and can represent contamination in some cases. Therapy is immunocompromised hosts is less than satisfactory and amphotericin B is the only agent with significant activity. There is anecdotal evidence to suggest that the addition of 5-fluorocytosine to amphotericin B may be beneficial.
Insights
Aspergillus spores can cause allergic diseases in healthy individuals and invasive infections in immunocompromised patients. Invasive aspergillosis, often caused by Aspergillus fumigatus, presents diagnostic and therapeutic challenges.
Area of Science:
- Mycology
- Infectious Diseases
- Clinical Medicine
Background:
- Aspergillus spores are widespread environmental contaminants, frequently found in hospital air systems.
- While normal hosts may develop allergic conditions like asthma, invasive aspergillosis predominantly affects severely immunocompromised individuals.
Purpose of the Study:
- To review the clinical significance of Aspergillus species, focusing on predisposing factors, common infections, and therapeutic strategies.
- To highlight the diagnostic difficulties and treatment limitations for invasive aspergillosis.
Main Methods:
- Literature review of Aspergillus infections.
- Analysis of predisposing factors and clinical manifestations.
- Evaluation of diagnostic methods and therapeutic outcomes.
Main Results:
- Aspergillus colonization can lead to allergic diseases in normal hosts.
- Invasive disease is linked to neutropenia, corticosteroid use, prosthetic devices, and tissue trauma.
- Pulmonary and sinus infections are common, with Aspergillus fumigatus being the primary pathogen.
- The organism invades tissues, including blood vessels, causing thrombosis and infarction.
- Diagnosis is challenging due to low sputum culture yield.
- Therapy for invasive aspergillosis is often unsatisfactory, with amphotericin B being a key agent.
Conclusions:
- Aspergillus poses a significant threat, particularly to immunocompromised patients.
- Effective diagnosis and treatment of invasive aspergillosis remain critical challenges in clinical practice.
- Combination therapy with amphotericin B and 5-fluorocytosine may offer potential benefits.