Aspergillosis

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.

Invasive pulmonary aspergillosis in neutropenic patients during hospital construction: Before and after chemoprophylaxis and institution of HEPA filters

“…Prolonged neutropenia has been the major risk factor for invasive aspergillosis [1,2]. In the immunocompromised or neutropenic host, invasive pulmonary aspergillosis (IPA) characterized by hyphal invasion and destruction of pulmonary tissue is the most common manifestation of an aspergillus infection, although local infections also occur in the sinuses, the skin, or intravenous catheter sites [3][4][5][6].…”

“…Recent data from a major teaching hospital in Frankfurt, Germany, showed a 14-fold increase in the number of cases over the years 1978-1992 [7]. Clinical reports show that the incidence of IPA differs greatly worldwide, at different treatment centers, and even within the same institution, ranging from as low as 0% to 25% or more [3,4]. The still unsatisfactory diagnosis and treatment of IPA result in an overall mortality of more than 50% in immunocompromised hosts [3,8].…”

“…Clinical reports show that the incidence of IPA differs greatly worldwide, at different treatment centers, and even within the same institution, ranging from as low as 0% to 25% or more [3,4]. The still unsatisfactory diagnosis and treatment of IPA result in an overall mortality of more than 50% in immunocompromised hosts [3,8]. The mortality of patients after allogeneic BMT can even be as high as 95% [8].…”

“…Several strategies for the prevention of IPA have been investigated: reduction of environmental exposure using a specialized air-handling system capable of excluding Aspergillus spores, such as HEPA filtration with or without laminar air flow ventilation [3,10,11] which has been very efficacious, augmentation of the natural host defense mechanisms by recombinant growth factors [12], and chemoprophylaxis with intravenous (i.v.) low-dose Amphotericin B (AB) [13][14][15], AB inhalations [16,17], intranasal AB [18,19], or Itraconazole [19], all showed variable success.…”

Value of different methods for the characterisation of Aspergillus terreus strains

“…Most infections in man occur in severely immunocompromised patients [2]. A. furnigatus represents the most common agent of systemic infections, followed by A. jlavus [2]. A. terreus is widespread in the environment, particularly in soil and on decaying vegetation [l].…”