Efficacy of deoxycholate amphotericin B and unilamellar liposomal amphotericin B in prophylaxis of experimental Aspergillus fumigatus endocarditis

Rodent Models of Invasive Aspergillosis due to Aspergillus fumigatus: Still a Long Path toward Standardization

Invasive aspergillosis has been studied in laboratory by the means of plethora of distinct animal models. They were developed to address pathophysiology, therapy, diagnosis, or miscellaneous other concerns associated. However, there are great discrepancies regarding all the experimental variables of animal models, and a thorough focus on them is needed. This systematic review completed a comprehensive bibliographic analysis specifically-based on the technical features of rodent models infected with Aspergillus fumigatus. Out the 800 articles reviewed, it was shown that mice remained the preferred model (85.8% of the referenced reports), above rats (10.8%), and guinea pigs (3.8%). Three quarters of the models involved immunocompromised status, mainly by steroids (44.4%) and/or alkylating drugs (42.9%), but only 27.7% were reported to receive antibiotic prophylaxis to prevent from bacterial infection. Injection of spores (30.0%) and inhalation/deposition into respiratory airways (66.9%) were the most used routes for experimental inoculation. Overall, more than 230 distinct A. fumigatus strains were used in models. Of all the published studies, 18.4% did not mention usage of any diagnostic tool, like histopathology or mycological culture, to control correct implementation of the disease and to measure outcome. In light of these findings, a consensus discussion should be engaged to establish a minimum standardization, although this may not be consistently suitable for addressing all the specific aspects of invasive aspergillosis.

The contribution of animal models of aspergillosis to understanding pathogenesis, therapy and virulence

Animal models of aspergillosis have been used extensively to study various aspects of pathogenesis, innate and acquired host-response, disease transmission and therapy. Several different animal models of aspergillosis have been developed. Because aspergillosis is an important pulmonary disease in birds, avian models have been used successfully to study preventative vaccines. Studies done to emulate human disease have relied on models using common laboratory animal species. Guinea pig models have primarily been used in therapy studies of invasive pulmonary aspergillosis (IPA). Rabbits have been used to study IPA and systemic disease, as well as fungal keratitis. Rodent, particularly mouse, models of aspergillosis predominate as the choice for most investigators. The availability of genetically defined strains of mice, immunological reagents, cost and ease of handling are factors. Both normal and immunosuppressed animals are used routinely. These models have been used to determine efficacy of experimental therapeutics, comparative virulence of different isolates of Aspergillus, genes involved in virulence, and susceptibility to infection with Aspergillus. Mice with genetic immunological deficiency and cytokine gene-specific knockout mice facilitate studies of the roles cells, and cytokines and chemokines, play in host-resistance to Aspergillus. Overall, these models have been critical to the advancement of therapy, and our current understanding of pathogenesis and host-resistance.

Aspergillus valve endocarditis in patients without prior cardiac surgery

Aspergillus native valve endocarditis in patients who have not had cardiac surgery is uncommon. We report 3 cases and review 58 other adult patients reported in the English-language literature. Sixty-seven percent of the patients had underlying immunosuppression. The clinical features were fever (74%), embolic episodes (69%), a new or changing heart murmur (41%), and sudden visual loss (13%). Patients with mural endocarditis were more often immunosuppressed, especially due to solid organ transplants, but had lower frequency of heart murmurs and embolic episodes. Echocardiography revealed a vegetation in 78% of all the cases in which it was performed. Examination and culture of biopsy material often helped to establish a diagnosis of Aspergillus infection. Twenty-five patients had an antemortem diagnosis. These patients received a mean cumulative amphotericin B dose of 27 mg/kg. Twenty percent (3/15) of patients who received combined surgical and medical therapy survived, compared to none of those who received medical therapy alone (p = 0.08). Patients who survived were not immunosuppressed. We conclude that native valve aspergillus infective endocarditis is uniformly fatal without surgical intervention and antifungal therapy.

Pulmonary aspergillosis and invasive disease in AIDS: review of 342 cases

Aspergillosis is an infrequent but commonly fatal infection among HIV-infected individuals. We review 342 cases of pulmonary Aspergillus infection that have been reported among HIV-infected patients, with a focus on invasive disease. Invasive pulmonary aspergillosis usually occurs among patients with <50 CD4 cells/mm3. Major predisposing conditions include neutropenia and steroid treatment. Fever, cough, and dyspnea are each present in >60% of the cases. BAL is often suggestive, but biopsy specimens are necessary for definite diagnosis. Amphotericin B is the mainstay of treatment and mortality is > 80%. Avoiding neutropenia and judicious use of steroids may be helpful in prevention. Aggressive diagnostic approach, early initiation of treatment, adequate dosing of antifungals, and close follow-up may improve the currently dismal prognosis.

Pulmonary invasive aspergillosis in patients infected with the human immunodeficiency virus: report of two cases

Patients infected with the human immunodeficiency virus (HIV) have an increased frequency of invasive aspergillosis. We report two cases of invasive pulmonary aspergillosis in patients infected with HIV. Patients had less than 10 CD4 (helper cell) cells/mm3 (2/2), presented with fever (2/2), dyspnea (1/2), and abnormal chest radiograph (2/2). Diagnosis was established by transbronchial biopsy (1/2) and autopsy (1/2). Patients died in spite of treatment with intravenous deoxycholate amphotericin B. Prognosis of invasive pulmonary aspergillosis among patients infected with HIV remains dismal, even with aggressive antifungal treatment.