Quantitative galactomannan detection is superior to PCR in diagnosing and monitoring invasive pulmonary aspergillosis in an experimental rat model.
(65/1936)
Two diagnostic tests, an Aspergillus-specific PCR and an enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of galactomannan, were compared for diagnosing and monitoring invasive pulmonary aspergillosis. Persistently neutropenic rats with left-sided invasive pulmonary aspergillosis were sacrificed at regular intervals after inoculation. Blood samples and bronchoalveolar lavage (BAL) fluid were cultured and tested by PCR as well as by ELISA. Disseminated fungal infection in extrapulmonary organs was determined. The sensitivity of the ELISA was higher than that of the PCR on all days of measurements, in both blood and BAL fluid. Positive PCR or ELISA results in blood were not significantly associated with disseminated fungal infection. Serial testing in a separate group of rats showed consistently increasing concentrations of circulating galactomannan during the course of disease, while a positive PCR could be followed by negative results. The concentration of galactomannan was highly predictive for the time of survival (P < 0.0001). It was concluded that, in this model, quantitative galactomannan detection is superior to PCR in diagnosing and monitoring invasive pulmonary aspergillosis. (+info)
Identification of Aspergillus species using internal transcribed spacer regions 1 and 2.
(66/1936)
Aspergillus species are the most frequent cause of invasive mold infections in immunocompromised patients. Although over 180 species are found within the genus, 3 species, Aspergillus flavus, A. fumigatus, and A. terreus, account for most cases of invasive aspergillosis (IA), with A. nidulans, A. niger, and A. ustus being rare causes of IA. The ability to distinguish between the various clinically relevant Aspergillus species may have diagnostic value, as certain species are associated with higher mortality and increased virulence and vary in their resistance to antifungal therapy. A method to identify Aspergillus at the species level and differentiate it from other true pathogenic and opportunistic molds was developed using the 18S and 28S rRNA genes for primer binding sites. The contiguous internal transcribed spacer (ITS) region, ITS 1-5.8S-ITS 2, from referenced strains and clinical isolates of aspergilli and other fungi were amplified, sequenced, and compared with non-reference strain sequences in GenBank. ITS amplicons from Aspergillus species ranged in size from 565 to 613 bp. Comparison of reference strains and GenBank sequences demonstrated that both ITS 1 and ITS 2 regions were needed for accurate identification of Aspergillus at the species level. Intraspecies variation among clinical isolates and reference strains was minimal. Sixteen other pathogenic molds demonstrated less than 89% similarity with Aspergillus ITS 1 and 2 sequences. A blind study of 11 clinical isolates was performed, and each was correctly identified. Clinical application of this approach may allow for earlier diagnosis and selection of effective antifungal agents for patients with IA. (+info)
Promoter elements involved in the expression of the Aspergillus parasiticus aflatoxin biosynthesis pathway gene avnA.
(67/1936)
One of the early genes in aflatoxin biosynthesis, avnA, encodes a pathway-specific cytochrome P-450 monooxygenase that catalyzes the hydroxylation of the polyketide anthraquinone, averantin. Based on beta-glucuronidase (GUS) reporter and electrophoretic mobility shift assays, promoter sites upstream of -118 bp in the 367-bp verB-avnA intergenic region are not required for avnA gene activity. Therefore, only the -100 to -110 site of the four putative binding sites for AFLR, the aflatoxin biosynthetic pathway transcription regulatory protein (consensus binding sequence: 5'-TCGN(5)CGR-3') was required for elevated avnA expression. (+info)
Characterization of the Aspergillus parasiticus major nitrogen regulatory gene, areA.
(68/1936)
The major nitrogen regulatory gene, areA, was cloned from Aspergillus parasiticus. It encoded a polypeptide of 864 amino acids which contained a nuclear localization signal (NLS), a highly acidic region from positions 497 to 542, a Cys-X(2)-Cys-X(17)-Cys-X(2)-Cys DNA-binding motif and a conserved carboxy-terminus. Electrophoretic mobility shift assays suggested that the A. parasiticus AREA DNA-binding domain fusion protein bound cooperatively to single GATA elements in the A. parasiticus niaD-niiA intergenic region. AREA also bound to the aflR-aflJ intergenic region of the aflatoxin biosynthesis gene cluster. Regions of areA were fused to a yeast GAL4 DNA-binding domain coding region to localize putative transcription activation domain(s) of AREA based on activation of the GAL1(p)::lacZ reporter gene expression. The portion between NLS and the acidic domain demonstrated 16-20-fold higher activation activities than other portions of AREA, which suggests that the transcription activation domain is located in this region. (+info)
Surgical treatment of aspergillus spondylodiscitis.
(69/1936)
Four cases of aspergillus spondylodiscitis were treated with operative debridement and fusion. In this rarely encountered mycotic infection of the spine in immunocompromised patients rapid destruction of the intervertebral disc and vertebral bodies can occur. In advanced cases antimycotic drug therapy is thought to be ineffective and a forcing indication for surgery exists when the destruction is progressive and spinal cord compression is imminent or manifest. Spinal instrumentation can be of help in maintaining or restoring spinal stability and maintaining spinal alignment. In our four patients the aspergillus spondylodiscitis was successfully eradicated and fusion achieved. In two of three patients with a neurologic deficit, this deficit disappeared. Two patients died within 6 months after the operative treatment, due to complications related to the underlying illness. One patient was left with a subtotal paraplegia. (+info)
Asymmetric reduction of ethyl 2-methyl e-oxobutanoate by fungi.
(70/1936)
Seven fungi, which are found to reduce ethyl 3-oxobutanoate in high yields, were tested for their reducing ability for ethyl 2-methyl 3-oxobutanoate. We obtained some interesting findings. In particular, Penicillium purpurogenum reduced ethyl 2-methyl 3-oxobutanoate to the corresponding alcohols with the diastereomer (anti/syn) ratio of 93/7 with the enantiomeric excess of anti-(2S,3S)- and syn-(2S,3R)- hydroxy esters of 90 and >99 ee%, respectively. (+info)
Practice guidelines for diseases caused by Aspergillus. Infectious Diseases Society of America.
(71/1936)
Aspergillosis comprises a variety of manifestations of infection. These guidelines are directed to 3 principal entities: invasive aspergillosis, involving several organ systems (particularly pulmonary disease); pulmonary aspergilloma; and allergic bronchopulmonary aspergillosis. The recommendations are distilled in this summary, but the reader is encouraged to review the more extensive discussions in subsequent sections, which show the strength of the recommendations and the quality of the evidence, and the original publications cited in detail. Invasive aspergillosis. Because it is highly lethal in the immunocompromised host, even in the face of therapy, work-up must be prompt and aggressive, and therapy may need to be initiated upon suspicion of the diagnosis, without definitive proof (BIII). Intravenous therapy should be used initially in rapidly progressing disease (BIII). The largest therapeutic experience is with amphotericin B deoxycholate, which should be given at maximum tolerated doses (e.g., 1-1.5 mg/kg/d) and should be continued, despite modest increases in serum creatinine levels (BIII). Lipid formulations of amphotericin are indicated for the patient who has impaired renal function or who develops nephrotoxicity while receiving deoxycholate amphotericin (AII). Oral itraconazole is an alternative for patients who can take oral medication, are likely to be adherent, can be demonstrated (by serum level monitoring) to absorb the drug, and lack the potential for interaction with other drugs (BII). Oral itraconazole is attractive for continuing therapy in the patient who responds to initial iv therapy (CIII). Therapy should be prolonged beyond resolution of disease and reversible underlying predispositions (BIII). Adjunctive therapy (particularly surgery and combination chemotherapy, also immunotherapy), may be useful in certain situations (CIII). Aspergilloma. The optimal treatment strategy for aspergilloma is unknown. Therapy is predominantly directed at preventing life-threatening hemoptysis. Surgical removal of aspergilloma is definitive treatment, but because of significant morbidity and mortality it should be reserved for high-risk patients such as those with episodes of life-threatening hemoptysis, and considered for patients with underlying sarcoidosis, immunocompromised patients, and those with increasing Aspergillus-specific IgG titers (CIII). Surgical candidates would need to have adequate pulmonary function to undergo the operation. Bronchial artery embolization rarely produces a permanent success, but may be useful as a temporizing procedure in patients with life-threatening hemoptysis. Endobronchial and intracavitary instillation of antifungals or oral itraconazole may be useful for this condition. Since the majority of aspergillomas do not cause life-threatening hemoptysis, the morbidity and cost of treatment must be weighed against the clinical benefit. Allergic bronchopulmonary aspergillosis (APBA). Although no well-designed studies have been carried out, the available data support the use of corticosteroids for acute exacerbations of ABPA (AII). Neither the optimal corticosteroid dose nor the duration of therapy has been standardized, but limited data suggest the starting dose should be approximately 0.5 mg/kg/d of prednisone. The decision to taper corticosteroids should be made on an individual basis, depending on the clinical course (BIII). The available data suggest that clinical symptoms alone are inadequate to make such decisions, since significant lung damage may occur in asymptomatic patients. Increasing serum IgE levels, new or worsening infiltrate on chest radiograph, and worsening spirometry suggest that corticosteroids should be used (BII). Multiple asthmatic exacerbations in a patient with ABPA suggest that chronic corticosteroid therapy should be used (BIII). Itraconazole appears useful as a corticosteroid sparing agent (BII). (ABSTRACT TRUNCATED) (+info)
Clinical evaluation of 61 patients with pulmonary aspergilloma.
(72/1936)
OBJECTIVE AND METHODS: We retrospectively evaluated 61 cases with pulmonary aspergilloma representing patients admitted to Nagasaki University Hospital between January 1991 to June 1998. RESULTS: Fifty-two (85%) were males and 9 (15%) were females, aged between 14 to 80 years (average, 65 years). Forty-four (72%) patients had history of old pulmonary tuberculosis. Chest radiographs showed "fungus ball" in the cavities in 42 (67%) cases while 16 (26%) cases showed thickening of the cavity wall. Aspergillus fumigatus was isolated in 24 (39%) patients. Aspergillus antigen or antibody was positive in 8 (13%) and 43 (70%) patients, respectively. Oral itraconazole was used in 16 (26%) of patients, and surgical excision was performed in 15 (25%) patients. During hospitalization or after discharge, 19 (31 %) patients died. SUMMARY AND CONCLUSION: Pulmonary aspergilloma usually occurs in elderly patients with old tuberculosis and respiratory failure. Many cases did not respond to antifungal therapy with itraconazole or amphotericin B. Our analysis indicates that more effective and appropriate therapeutic regimens are needed for the treatment of patients with pulmonary aspergilloma. (+info)