Comparison between PCR and detection of antigen in sera for diagnosis of pulmonary aspergillosis

Clinical characteristics and outcomes of pleural aspergillosis: a review of 13 cases

Aspergillus pleurisy is a rare complication of invasive pulmonary aspergillosis (IPA), which mostly occurs in the immunocompromised host. The clinical condition is critical, especially to those who develop bronchopleural fistula. This study aimed to assess the characteristics and the prognosis of aspergillus pleurisy. Clinical data from 13 patients diagnosed with aspergillus pleurisy in our hospital from January 2000 to December 2022 were retrospectively studied. Thirteen patients with Aspergillus pleurisy were included. There were 10 males and 3 females, with a median age of 65 (range: 18-79) years. Bronchopleural fistula was present in eight patients. A proven diagnosis of Aspergillus pleurisy was based on positive pleural fluid culture in seven cases and histopathological examination of pleural biopsies in six cases. Four patients refused further treatment and were discharged from the hospital against medical advice. Nine cases recovered and were discharged after multiple antifungal treatments (systemic and topical antifungal therapies, pleural drainage and irrigation, and surgical repair). During follow-up, one patient, who suffered underlying bronchiectasis, died of massive hemoptysis 2 years after discharge. The remaining eight cases are still under close follow-up, with a median follow-up of 5.4 (range: 1.3-18.9) years. The prognosis of aspergillus pleurisy complicated with bronchopleural fistula is poor. Thoracic surgery, especially lung resection, is a risk factor associated with the incidence of Aspergillus pleurisy. Systemic antifungal therapy and adequate pleural irrigation could improve the prognosis.

IMPORTANCE

Aspergillus pleurisy is a rare complication of invasive pulmonary aspergillosis (IPA), associated with a poor prognosis. The morbidity and mortality of this condition have not been thoroughly studied, and recent research on this topic is limited. The current study included 13 patients diagnosed with Aspergillus pleurisy, with the majority presenting concomitantly with a bronchopleural fistula. Among these patients, nine had a history of thoracic surgery, including lung transplantation and lobectomy. Four patients refused further treatment and were discharged against medical advice, while one patient succumbed to massive hemoptysis 2 years after discharge. This case series provides essential insights into Aspergillus pleurisy and evaluates the therapeutic strategy based on a limited cohort.

Systematic review and meta-analysis of galactomannan antigen testing in serum and bronchoalveolar lavage for the diagnosis of chronic pulmonary aspergillosis: defining a cutoff

BACKGROUND

A clear cutoff value of galactomannan (GM) has not been established for chronic pulmonary aspergillosis (CPA) and is frequently extrapolated from invasive pulmonary aspergillosis. We performed a systematic review and meta-analysis to evaluate the diagnostic performance of serum and bronchoalveolar lavage (BAL) GM, and to propose a cutoff.

METHODS

We extracted from the studies the cutoff of serum or/and BAL GM associated with true positives, false positives, true negatives, and false negatives. We performed a multi-cutoff model and a non-parametric random effect model. We estimated the optimal cutoff and the area under the curve (AUC) for GM in serum and BAL samples.

RESULTS

Nine studies from 1999 to 2021 were included. Overall, the optimal cutoff of serum GM was 0.96 with a sensitivity of 0.29 (95%CI: 0.14-0.51); specificity of 0.88 (95%CI: 0.73-0.95); and AUC of 0.529 (with a CI: [0.415-0.682] [0.307-0.713]). The AUC for the non-parametric ROC model was 0.631. For BAL GM the cutoff was 0.67 with a sensitivity of 0.68 (95%CI: 0.51-0.82), specificity of 0.84 (95%CI: 0.70-0.92), and AUC of 0.814 (with a CI: [0.696-0.895] [0.733-0.881]). The AUC for the non-parametric model was 0.789.

CONCLUSION

The diagnosis of CPA requires the assessment of a combination of mycological and serological factors, as no single serum and/or BAL GM antigen test is adequate. BAL GM performed better than serum, with better sensitivity and excellent accuracy.

Pulmonary Aspergillosis: An Evolving Challenge for Diagnosis and Treatment

Aspergillus is a mold that may lead to different clinical pictures, from allergic to invasive disease, depending on the patient’s immune status and structural lung diseases. Chronic pulmonary aspergillosis is an infection with a locally invasive presentation, reported especially in patients with chronic pulmonary disease, while aspergilloma is typically found in patients with previously formed cavities in the lungs. Allergic bronchopulmonary aspergillosis is due to a hypersensitivity reaction to Aspergillus antigens and is more frequently described in patients with moderate-severe asthma or cystic fibrosis. Invasive pulmonary aspergillosis mainly occurs in patients with neutropenia or immunodeficiency, but has increasingly been recognized as an emerging disease of non-neutropenic patients. The significance of this infection has dramatically increased in recent years, considering the high number of patients with an impaired immune state associated with the management and treatment of neoplasm, solid or hematological transplantation, autoimmune diseases, and inflammatory conditions. Moreover, prolonged steroid treatment is recognized as an important risk factor, especially for invasive disease. In this setting, critically ill patients admitted to intensive care units and/or with chronic obstructive pulmonary disease could be at higher risk for invasive infection. This review provides an update on the clinical features and risk factors of pulmonary aspergillosis. Current approaches for the diagnosis, management, and treatment of these different forms of pulmonary aspergillosis are discussed.

The spectrum of pulmonary aspergillosis

Notable progress has been made in the past years in the classification, diagnosis and treatment of pulmonary aspergillosis. New criteria were proposed by the Working Group of the International Society for Human and Animal Mycology (ISHAM) for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). The latest classification of chronic pulmonary aspergillosis (CPA) suggested by the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) has become widely accepted among clinicians. Subacute invasive pulmonary aspergillosis is now considered a type of CPA, yet it is still diagnosed and treated similarly to invasive pulmonary aspergillosis (IPA). Isavuconazole, an extended-spectrum triazole, has recently been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of IPA. The most recent Infectious Diseases Society of America (IDSA) guidelines strongly recommend reducing mold exposure to patients at high risk for pulmonary aspergillosis. The excessive relapse rate following discontinuation of therapy remains a common reality to all forms of this semi-continuous spectrum of diseases. This highlights the need to continuously reassess patients and individualize therapy accordingly. Thus far, the duration of therapy and the frequency of follow-up have to be well characterized.

Comparison of real-time PCR, nested PCR, and galactomannan antigen detection by enzyme-linked immunosorbent assay in sera for diagnosis of invasive aspergillosis

Conventional methods for diagnosis of invasive aspergillosis (IA) lack sensitivity and specificity. Serological methods still have many cases of cross-reactivity. However, molecular techniques seem to arise as a rapid approach, specific and direct that could be used in the diagnosis of IA. In this study, we analyzed 88 serum samples from patients of having IA using GM-ELISA test, nested PCR with primers for the rRNA 18S of Aspergillus genus and real time PCR specific for A. fumigatus. Among the 88 samples, 64 of them had positive GM titers and 23 had positive nested PCRs; 18 of the 23 PCR-positive samples were also GM-positive. On the other hand, 18 samples were detected positive by reel time PCR; 13 positive samples were also detecting positive by nested PCR. QPCR revealed 26 % of the patients with IA, while nested PCR and galactomannan ELISA revealed respectively 34 % and 94 % of the patients with IA. Probable IA was diagnosed in 18 and possible IA was diagnosed in 6 episodes. Forty-four episodes were defined as not having IA. The positive and negative predictive values were respectively 100 %, and 88 % for QPCR, 100 % and 97 % for nested PCR, and 28 % and 60 % for GM test. These results suggesting that combined use of methods might improve the diagnosis of IA.

Comparison of galactomannan, beta-D-glucan, and Aspergillus DNA in sera of high-risk adult patients with hematological malignancies for the diagnosis of invasive aspergillosis

BACKGROUND/AIM

Invasive aspergillosis (IA) is a fatal infection that is difficult to diagnose in immunocompromised patients. In this study, Aspergillus-specific DNA was searched using real-time PCR (RT-PCR) in serum samples. Galactomannan (GM) and/or beta-D-glucan (BDG) tests were previously performed on these samples for 70 neutropenic patients with hematological malignancy.

MATERIALS AND METHODS

The patients were categorized according to the criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG). Among the patient serum samples, the first positive GM or BDG test sample and the median sample of GM or BDG test for negative patients were used to detect DNA levels by RT-PCR method (Light Cycler 480, Roche Molecular Biochemicals, Meylan, France) using a commercial kit (Way2Gene Fungi; Genmar, İzmir, Turkey).

RESULTS

When the proven and probable IA group were considered as real patients, sensitivity of Aspergillus-specific DNA test was 90%, specificity was 73.3%, positive predictive value was 81.8%, and negative predictive value was 84.6%.

CONCLUSION

This study found that searching for specific DNA by RT-PCR method has a sensitivity as high as the GM test. Although specificity was rather low, it was concluded that it can be used jointly with GM and BDG tests after decreasing contamination by severe laboratory applications.

Aspergillus fumigatus fungus ball in the pleural cavity

OBJECTIVE

To report the cases of 6 patients with fungus ball caused by Aspergillus fumigatus (aspergilloma) in the pleural cavity.

METHODS

Between 1980 and 2009, 391 patients were diagnosed with aspergilloma at the Santa Casa Hospital Complex in Porto Alegre, Brazil. The diagnosis of aspergilloma in the pleural cavity was made through imaging tests revealing effusion and pleural thickening with air-fluid level; direct mycological examination revealing septate hyphae, consistent with Aspergillus sp.; and positive culture for A. fumigatus in the surgical specimen from the pleural cavity.

RESULTS

Of the 391 patients studied, 6 (2%) met the established diagnostic criteria. The mean age of those 6 patients was 48 years (range, 29-66 years), and 5 (83%) were male. The most common complaints were cough, expectoration, and hemoptysis. Four patients (67%) had a history of tuberculosis that had been clinically cured. All of the patients were submitted to surgical removal of the aspergilloma, followed by intrapleural instillation of amphotericin B, in 4; and 2 received systemic antifungal treatment p.o. There was clinical improvement in 5 patients, and 1 died after the surgery.

CONCLUSIONS

In adult patients with a history of cavitary lung disease or pleural fistula, a careful investigation should be carried out and fungal infection, especially aspergilloma, should be taken into consideration. In such cases, laboratory testing represents the most efficient use of the resources available to elucidate the diagnosis.

Comparison of PCR-ELISA and Real-Time PCR for invasive aspergillosis diagnosis in patients with hematological malignancies

This study aimed at comparing a real-time PCR assay and a PCR-ELISA assay of both serum and bronchoalveolar lavage (BAL) samples for the diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies. Using a nested case-control design, 163 patients at risk were prospectively monitored and PCR assays were performed on frozen aliquots of 459 sera which were prospectively sampled twice weekly and 42 BAL specimens sampled from 43 probable and one proven IA cases and 47 matched controls. The data from three patients classified as possible IA were excluded from the nested case-control study. The sensitivity of real-time PCR and PCR-ELISA assays in serum was 73% and 86%, respectively and specificity was 100% for both. In BAL, sensitivity was 64% for real-time PCR, 71% for PCR-ELISA and 86% for Galactomannan antigen (GMA) assays with specificities of 96%, 96%, and 93%, respectively. While slightly less sensitive, the real time-PCR assay was highly specific and considerably faster and more workable than PCR-ELISA. Combining real-time PCR and GMA detection for both serum and BAL samples enhances routine laboratory IA diagnosis.

Galactomannan on the stage: prospective evaluation of the applicability in routine practice and surveillance

Invasive aspergillosis (IA) presents a diagnostic and therapeutic dilemma for the physicians who take care of the patients with severe underlying diseases and immunosuppression. This study aimed to evaluate the usefulness of serum galactomannan (GM) measurements in the routine practice and surveillance of IA along with possible caveats in diagnosis and treatment. Adult patients with high-risk haematological malignancies admitted to the Internal Medicine wards during the 2-year study period were followed up by daily visits for vital signs, existing or newly developing signs and symptoms, clinical and laboratory findings. Blood samples were analysed for GM levels by the ELISA method at the end of the study period. Data of 58 hospitalisation episodes in 45 patients were analysed. Proven IA was diagnosed in one patient, probable IA was diagnosed in four patients. The sensitivity was 60% and the specificity was 21% when the index cut-off for positivity was accepted as 0.5. The yield of GM testing may be influenced by many variables and each centre should evaluate the usefulness of this test in its own conditions.

Current status and future perspectives on molecular and serological methods in diagnostic mycology

Invasive fungal infections are an important cause of infectious morbidity. Nonculture-based methods are increasingly used for rapid, accurate diagnosis to improve patient outcomes. New and existing DNA amplification platforms have high sensitivity and specificity for direct detection and identification of fungi in clinical specimens. Since laboratories are increasingly reliant on DNA sequencing for fungal identification, measures to improve sequence interpretation should support validation of reference isolates and quality control in public gene repositories. Novel technologies (e.g., isothermal and PNA FISH methods), platforms enabling high-throughput analyses (e.g., DNA microarrays and Luminex® xMAP™) and/or commercial PCR assays warrant further evaluation for routine diagnostic use. Notwithstanding the advantages of molecular tests, serological assays remain clinically useful for patient management. The serum Aspergillus galactomannan test has been incorporated into diagnostic algorithms of invasive aspergillosis. Both the galactomannan and the serum β-D-glucan test have value for diagnosing infection and monitoring therapeutic response.

Current Molecular Diagnostic Approaches to Systemic Infections withAspergillusSpecies in Patients with Hematological Malignancies

Within the recent years, novel molecular methods, especially PCR assays, have been developed to improve the diagnosis of invasive aspergillosis in patients with malignant hematological diseases being at high risk for this life-threatening infection. Early diagnosis and treatment are essential for adequate therapeutical management, which however, often remains difficult since most of the diagnostic tools used clinically at present either lack specificity or acceptable sensitivity. The clinical value, advantages and remaining problems of recently developed molecular approaches to detect the emerging fungal pathogen are reviewed.

An update on the molecular diagnosis of invasive fungal disease

Despite improvements in medical technology, the definitive diagnosis of invasive fungal disease (IFD) is limited. The prevalence of disease is relatively low but many cases are undiagnosed. With the diagnosis of proven IFD dependent on histopathology or culture from a sterile site, clinicians have become more reliant on noninvasive nonculture diagnostic techniques. PCR technology has the capacity to overcome classical limitations but has its own drawbacks, resulting from an incomplete knowledge of the various disease processes and subsequent shortage of optimal specimens, leading to a lack of methodological standardization. This review will consider the general principles and limitations of fungal PCR before discussing genus-specific PCR applications. It is by no means a systematic review of the literature but is intended, where possible, to provide the reader with access to assays with proficient clinical performance.

Fungal pneumonia due to molds in patients with hematological malignancies

Invasive fungal infections are an important cause of morbidity and mortality in patients with hematological malignancies. In particular, patients with neutropenia and those who have undergone allogeneic hematopoietic stem cell transplantation are at highest risk, with fungal pneumonia being the main clinical manifestation in these patients. The most common pathogens associated with fungal pneumonia are Aspergillus spp. and Zygomycetes. However, other pathogens have also been observed in fungal pneumonia, including Cryptococcus spp., Pneumocystis jirovecii, and Candida spp. This comprehensive review will focus on the important practical aspects relevant to the epidemiology, clinical diagnosis, and therapeutic management of pneumonia due to filamentous fungi in patients affected by hematological malignancies.

Chronic necrotizing pulmonary aspergillosis as a complication of pulmonary Mycobacterium avium complex disease

OBJECTIVE AND BACKGROUND

To investigate the characteristic clinical features of chronic necrotizing pulmonary aspergillosis (CNPA) as a complication of pulmonary Mycobacterium avium complex (MAC) disease.

METHODS

Clinical analysis of nine cases without a history of old pulmonary tuberculosis in whom CNPA was found to be a complication during the follow-up period for MAC disease.

RESULTS

The average duration from the diagnosis of pulmonary MAC disease to the diagnosis of CNPA was 36.0 months. Five patients received antituberculous therapy including clarithromycin for pulmonary MAC disease, but this treatment was ineffective in most. A positive culture for Aspergillus spp. from sputum and a bronchoscopic specimen and clinical evidence of a chronic infective process were recognized in all cases at the time of detection of CNPA. Serological fungal examinations for anti-Aspergillus IgG antibody were initially negative and became positive in all cases during the follow-up period of pulmonary MAC disease. The presence of CNPA surrounding the cavity previously caused by MAC was characterized by local thickening of the cavity with a fungus ball and the appearance of an infiltration shadow surrounding the cavity. In most of the cases, CNPA was at first treated with oral itriconazole and then with i.v. infusion of micafungin, but the clinical efficacy was generally poor.

CONCLUSION

The results of this study showed that during the long follow-up period of patients with pulmonary MAC disease it is important to not only carry out serological examinations, but also perform radiological examinations using chest CT.

Diagnosis of aspergilloma in a pleural cavity (persistent pneumothorax) using classic imaging methods

The diagnosis of pulmonary aspergillosis is based on serum-analysis, as well as histological and microbiological analysis of bronchial lavage and transbronchial biopsies. When Aspergillus develops within a preformed cavity, however, these tests are likely to be negative. In this situation, classic imaging techniques such as chest X-ray and high resolution-computed tomography (HR-CT) can be of great diagnostic use. We here describe the case of a 62-year-old woman with a history of breast cancer and subsequent ablation of the left breast and radiotherapy. The case demonstrates an example of a pleuropulmonary aspergilloma, in which sero- and micro-biological detection failed. Thorax HR-CT exhibited the cavity, a small persistent pneumothorax, partially filled by an oval density. This density clearly dislocated according to gravity following a positional change of the patient from supine to prone. The density thus revealed mobility which was typical of aspergilloma. Following excision, this diagnosis was confirmed. A density within a cavity may be differentiated by its mobility from differential diagnoses such as lung cancer which would not be expected to exhibit mobility.

Evaluation of the role of real-time PCR in the diagnosis of invasive aspergillosis

Recently, two developments relating to the diagnosis of invasive aspergillosis (IA) have occurred. First, the standardisation of criteria for determining the category of this disease according to the European Organisation for Research and Treatment of Cancer/Mycosis (EORTC) Study Group consensus definitions has allowed comparison of results from different studies to be undertaken. The second development is the generation of PCR assays based on real-time technologies that are able to quantify Aspergillus DNA. In this review the benefits and limitations of these new published assays are compared with nested-PCR assays and enzyme immuno assays. Results from studies where these real-time assays have been used and patient's infections were classified according the EORTC definitions are examined. The effect of anti-fungal treatment is noted. The requirement for both international standards and a consensus protocol that is sensitive enough for IA diagnosis, particularly in blood, is discussed.

The evolution and evaluation of a whole blood polymerase chain reaction assay for the detection of invasive aspergillosis in hematology patients in a routine clinical setting

BACKGROUND

Invasive aspergillosis (IA) is associated with high mortality. Successful outcome with treatment is linked to early diagnosis. The utility of classic diagnostic methods, however, is limited.

METHODS

To aid in the diagnosis of IA, we retrospectively assessed our diagnostic service, using real-time polymerase chain reaction (PCR) and galactomannan sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

A total of 203 patients at risk of invasive fungal infection were screened by PCR, and 116 of the patients were also tested by ELISA. The patient group comprised 176 patients with hematological malignancy and 28 control patients with evidence of invasive candidal infection. Consensus European Organisation for Research and Treatment of Cancer and Mycoses Study Group criteria were used to classify fungal infection, which, by definition, excluded the PCR result. The PCR method was sensitive (up to 92.3% sensitivity) and specific (up to 94.6% specificity) and had good agreement with the galactomannan ELISA (76.7%) and high-resolution computed tomography scan results.

CONCLUSIONS

A negative PCR result can be used to rule out IA and to limit the need for empirical antifungal therapy; thus, it has a role in diagnosing IA infections, especially in combination with antigen testing. PCR-positive cases classified as "false positives" regularly reflect the limitations of classic microbiological procedures or restricted use of consensus clinical methods employed to classify infection.

Aspergillus PCR - Platforms, strengths and weaknesses

PCR is a useful tool to aid in the diagnosis of invasive aspergillosis. However, it is essential that an optimal method be agreed to allow inclusion in future consensus diagnosis criteria. It should be used in conjunction with other methods (e.g., galatomannan (GM) ELISA and high resolution computed tomography (HRCT)) to enhance the opportunity for detection of this devastating infection. This manuscript will try to highlight the benefits but mainly the limitations occurring throughout the process of molecular testing. It will focus on real-time methods although many of the points will be relevant to block-based amplification.

Use of real-time PCR to process the first galactomannan-positive serum sample in diagnosing invasive aspergillosis

Positive galactomannan (GM) anti-genemias are included as a microbiological item in the diagnosis of probable or possible invasive aspergillosis (IA). Because false-positive GM results frequently occur, at least two positive results on two different samples are required. Waiting for clinical specimens can delay the initiation of treatment. As an alternative, we wondered whether detection of circulating Aspergillus DNA on the first positive GM serum sample could aid in diagnosing IA. Therefore, we retrospectively screened the first GM-positive serum samples from 29 patients from our hematology unit for Aspergillus DNA using real-time PCR. We compared the real-time PCR results with the final classification of proven, probable, and possible IA according to consensual criteria. No clear correlation between PCR results and the classification with the medical files could be shown. However, a positive PCR result was associated with a poor prognosis (Fisher's test; P=0.01). Our preliminary data suggest that a positive PCR result could indicate a more advanced stage of the disease. Therefore, concomitant positive PCR and GM results may justify the initiation of antifungal therapy in neutropenic patients. In contrast, a negative PCR on the first positive GM sample may argue for postponing costly antifungal administration until additional arguments for the diagnosis of IA are presented.

Comparison of PCR-ELISA and galactomannan detection for the diagnosis of invasive aspergillosis

AIM

To compare PCR with galactomannan antigen detection for the diagnosis of invasive aspergillosis (IA).

METHODS

We prospectively collected serial blood samples from haematological patients at risk of IA, and analysed their samples retrospectively for galactomannan (GM) antigen using the Platelia test and for aspergillus DNA using an in-house PCR-ELISA assay. Matched GM and PCR analyses were performed on 263 samples from 25 patients. Patients were classified for potential IA according to international consensus criteria, with five patients classified as positive (four proven, one probable) and 20 classified as negative (seven possible, 13 no evidence IA).

RESULTS

All five patients with IA were positive by PCR with positive results in 24 of 82 samples, whereas three of five patients were positive by GM with four of 82 samples being positive. Three of 20 patients without IA were positive by PCR in 18 of 181 samples, whereas corresponding results for GM detection were one of 20 and one of 181, respectively. Adjustment of ELISA cut-off values and/or the requirement for two consecutive samples to be positive generated different results; however, lowering the positivity index (PI) for GM detection to 0.5 did not improve the sensitivity of the assay. Optimal results for PCR detection and GM were: 100% and 60% sensitivity, 85% and 95% specificity, 0.625 and 0.75 positive predictive value, and 1.0 and 0.8 negative predictive value, with a false-positive sample rate of 8 and 0.4%, positive likelihood ratio of 6.66 and 11.99 and negative likelihood ratio of 0 and 0.42, respectively.

CONCLUSIONS

This PCR method is very sensitive for the diagnosis of IA but is associated with a moderate rate of false positives; the GM assay exhibited poor sensitivity but high specificity. Further evaluation of PCR assays for the diagnosis of IA and other invasive fungal infections is warranted.

Design Issues in Studies Evaluating Diagnostic Tests for Aspergillosis

Although invasive aspergillosis is recognized as an increased concern for immunosuppressed patients, establishing an early diagnosis remains a challenge. Current methods for diagnosis, including sensitive radiography and invasive procedures to identify organisms in affected tissues, provide an early diagnosis for only a small proportion of patients infected with Aspergillus species. The availability of a standardized assay to detect circulating Aspergillus galactomannan, the BioRad Platelia Aspergillus galactomannan enzyme immunoassay, should be considered as a valuable tool. However, at present, clinical utility is hampered by controversies surrounding the performance of the test and an apparent lack of definitive data. These controversies emphasize the complexity inherent in analyzing diagnostic tests for aspergillosis. The widespread availability of a standardized assay may now allow us to address the multiple sources of variability and bias via large, cooperative studies.

Comparison of non-culture-based methods for detection of systemic fungal infections, with an emphasis on invasive Candida infections

The accepted limitations associated with classic culture techniques for the diagnosis of invasive fungal infections have lead to the emergence of many non-culture-based methods. With superior sensitivities and quicker turnaround times, non-culture-based methods may aid the diagnosis of invasive fungal infections. In this review of the diagnostic service, we assessed the performances of two antigen detection techniques (enzyme-linked immunosorbent assay [ELISA] and latex agglutination) with a molecular method for the detection of invasive Candida infection and invasive aspergillosis. The specificities for all three assays were high (> or = 97%), although the Candida PCR method had enhanced sensitivity over both ELISA and latex agglutination with values of 95%, 75%, and 25%, respectively. However, calculating significant sensitivity values for the Aspergillus detection methods was not feasible due to a low number of proven/probable cases. Despite enhanced sensitivity, the PCR method failed to detect nucleic acid in a probable case of invasive Candida infection that was detected by ELISA. In conclusion, both PCR and ELISA techniques should be used in unison to aid the detection of invasive fungal infections.

Aspergilluspolymerase chain reaction (PCR) diagnosis

In recent years novel molecular methods, notably polymerase chain reaction (PCR) assays, have been developed to improve the diagnosis of life-threatening invasive aspergillosis in patients at high risk, especially patients with malignant hematological disease. Early diagnosis and treatment are essential for adequate therapeutic management. Management, however, often remains difficult since most of the diagnostic tools used clinically at present either lack specificity or acceptable sensitivity. The clinical value, advantages and remaining problems of PCR approaches to detect the emerging fungal pathogen are reviewed.

Use of lung resection and voriconazole for successful treatment of invasive pulmonary Aspergillus ustus infection

Invasive pulmonary aspergillosis (IPA) is a common infection in neutropenic patients and is associated with high mortality. Aspergillus ustus is a species that has only rarely been implicated in human disease. All reported cases of IPA due to A. ustus have been fatal. Here, we describe a case of invasive pulmonary A. ustus infection successfully treated with lung resection and voriconazole. A 43-year-old man with acute myeloid leukemia underwent two courses of chemotherapy and experienced prolonged neutropenia. Treatment with amphotericin B was given for persistent fever. While he was receiving amphotericin B, a progressive opacity developed in the upper right lobe. Lung tissue obtained through pulmonary wedge resection for histology showed a mold with septate hyphae, consistent with IPA due to Aspergillus. A. ustus was grown in culture. The patient was then treated with voriconazole and remained in remission of the mold infection in spite of additional chemotherapy and a leukemic relapse. In summary, this report describes the successful treatment of invasive pulmonary A. ustus infection by lung resection and antifungal treatment with voriconazole in a neutropenic patient.

Polymerase chain reaction in the diagnosis of invasive aspergillosis

In the present study, we present a patient with invasive pulmonary aspergillosis caused by Aspergillus fumigatus diagnosed by polymerase chain reaction (PCR) technique on blood and bronchoalveolar lavage fluid samples of the patient. The value of PCR in the diagnosis of aspergillosis is discussed.

Rapid differentiation of Aspergillus species from other medically important opportunistic molds and yeasts by PCR-enzyme immunoassay

We developed a PCR-based assay to differentiate medically important species of Aspergillus from one another and from other opportunistic molds and yeasts by employing universal, fungus-specific primers and DNA probes in an enzyme immunoassay format (PCR-EIA). Oligonucleotide probes, directed to the internal transcribed spacer 2 region of ribosomal DNA from Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus terreus, Aspergillus ustus, and Aspergillus versicolor, differentiated 41 isolates (3 to 9 each of the respective species; P < 0.001) in a PCR-EIA detection matrix and gave no false-positive reactions with 33 species of Acremonium, Exophiala, Candida, Fusarium, Mucor, Paecilomyces, Penicillium, Rhizopus, Scedosporium, Sporothrix, or other aspergilli tested. A single DNA probe to detect all seven of the most medically important Aspergillus species (A. flavus, A. fumigatus, A. nidulans, A. niger, A. terreus, A. ustus, and A. versicolor) was also designed. Identification of Aspergillus species was accomplished within a single day by the PCR-EIA, and as little as 0.5 pg of fungal DNA could be detected by this system. In addition, fungal DNA extracted from tissues of experimentally infected rabbits was successfully amplified and identified using the PCR-EIA system. This method is simple, rapid, and sensitive for the identification of medically important Aspergillus species and for their differentiation from other opportunistic fungi.

Prospective comparison of the diagnostic potential of real-time PCR, double-sandwich enzyme-linked immunosorbent assay for galactomannan, and a (1-->3)-beta-D-glucan test in weekly screening for invasive aspergillosis in patients with hematological disorders

The establishment of an optimal noninvasive method for diagnosing invasive aspergillosis (IA) is needed to improve the management of this life-threatening infection in patients with hematological disorders, and a number of noninvasive tests for IA that target different fungal components, including galactomannan, (1-->3)-beta-d-glucan (BDG), and Aspergillus DNA, have been developed. In this study, we prospectively evaluated the diagnostic potential of three noninvasive tests for IA that were used in a weekly screening strategy: the double-sandwich enzyme-linked immunosorbent assay (ELISA) for galactomannan (Platelia Aspergillus), a real-time PCR assay for Aspergillus DNA (GeniQ-Asper), and an assay for BDG (beta-glucan Wako). We analyzed 149 consecutive treatment episodes in 96 patients with hematological disorders who were at high risk for IA and diagnosed 9 proven IA cases, 2 probable IA cases, and 13 possible invasive fugal infections. In a receiver-operating characteristic (ROC) analysis, the area under the ROC curve was greatest for ELISA, using two consecutive positive results (0.97; P = 0.036 for ELISA versus PCR, P = 0.055 for ELISA versus BDG). Based on the ROC curve, the cutoff for the ELISA could be reduced to an optical density index (O.D.I.) of 0.6. With the use of this cutoff for ELISA and cutoffs for PCR and BDG that give a comparable level of specificity, the sensitivity/specificity/positive predictive value/negative predictive value of the ELISA and the PCR and BDG tests were 1.00/0.93/0.55/1.00, 0.55/0.93/0.40/0.96, and 0.55/0.93/0.40/0.96, respectively. In conclusion, among these weekly screening tests for IA, the double-sandwich ELISA test was the most sensitive at predicting the diagnosis of IA in high-risk patients with hematological disorders, using a reduced cutoff of 0.6 O.D.I.

Detection of Aspergillus galactomannan by enzyme immunoabsorbent assay in recipients of allogeneic hematopoietic stem cell transplantation: a prospective study

BACKGROUND

Invasive aspergillosis (IA) has become the leading infectious cause of death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This is partially because of the lack of a sensitive, specific, and noninvasive diagnostic test. New diagnostic tests for IA, such as the detection of Aspergillus galactomannan antigen (AGA) by sandwich enzyme-linked immunoabsorbent assay (ELISA), have recently been described. This study validates the usefulness of this diagnostic tool in the allo-HSCT setting.

METHODS

From January 1999 to January 2001, all consecutive adult patients undergoing allo-HSCT were prospectively studied with a galactomannan antigenemia assay (ELISA test) twice weekly from admission until death or discharge, and weekly afterward if the patient received immunosuppressive therapy. Proven, probable, and possible IA were defined according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria.

RESULTS

During the 2 years of study, 74 patients underwent an allo-HSCT. A total of 832 serum samples were collected. According to the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria, it was ascertained that 66 patients did not fulfill any criteria of IA, 2 patients were classified with possible IA, 5 patients were classified with probable IA, and 1 patient was classified with proven IA. Fourteen samples were positive for AGA, all from patients with IA. The sensitivity and specificity of the test were 75% and 100%, respectively. The positive predictive and negative predictive values were 100% and 97%, respectively.

CONCLUSIONS

In this study, AGA detection was clearly related to IA. Although the ELISA test did not have any role in the anticipation of the diagnosis, it clarifies the diagnosis of IA in allo-HSCT.

New developments in antifungal strategy

The increasing importance of invasive fungal infection as a cause of severe morbidity and mortality in immunocompromised patients has fuelled the development of new antifungal agents, including new triazole agents and echinocandins. Failure to diagnose fungal infection adequately has hampered the evaluation of these drugs in clinical trials. Consequently, the evidence base behind many prophylactic and empirical treatment strategies has been poor. Recent advances have improved diagnostic criteria and opened the way for more rational usage of these expensive preparations. The proven efficacy and improved safety profile of newer agents is a major advantage. Furthermore, better understanding of the immune response may allow novel strategies of adjunctive therapy and immunomodulation.

Invasive aspergillosis in patients with hematologic malignancies

Invasive aspergillosis is an increasingly common and often fatal opportunistic fungal infection in patients with hematologic malignancies. Prolonged and profound neutropenia remains a key risk factor for the development of invasive aspergillosis. However, qualitative deficiencies in host immune responses resulting from prolonged corticosteroid therapy, graft-versus-host disease, and cytomegalovirus infection are important risk factors for the recurrence and progression of Aspergillus infections after bone marrow recovery. Early diagnosis of invasive aspergillosis remains a challenge, and few tools are available for monitoring its course once the diagnosis is established. Even with the recent introduction of new antifungal therapies, mortality in patients with invasive aspergillosis remains high, and uniformly effective prophylaxis or preemptive therapeutic strategies are lacking. Strategies such as combination antifungal therapy and immunotherapy often are used as first-line treatment approaches in patients with documented invasive aspergillosis despite a paucity of clinical trial data. Recent advances in our understanding of the epidemiology, pathogenesis, and treatment of invasive aspergillosis in patients with hematologic malignancies are reviewed. The problems and controversies associated with defining optimal treatment strategies for invasive aspergillosis in this heavily immunocompromised population are highlighted.

Development and validation of a quantitative real-time PCR assay using fluorescence resonance energy transfer technology for detection of Aspergillus fumigatus in experimental invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis (IPA) is a frequently fatal infection in immunocompromised patients that is difficult to diagnose. Present methods for detection of Aspergillus spp. in bronchoalveolar lavage (BAL) fluid and in tissue vary in sensitivity and specificity. We therefore developed an A. fumigatus-specific quantitative real-time PCR-based assay utilizing fluorescent resonance energy transfer (FRET) technology. We compared the assay to quantitative culture of BAL fluid and lung tissue in a rabbit model of experimental IPA. Using an enzymatic and high-speed mechanical cell wall disruption protocol, DNA was extracted from samples of BAL fluid and lung tissues from noninfected and A. fumigatus-infected rabbits. A unique primer set amplified internal transcribed spacer regions (ITS) 1 and 2 of the rRNA operon. Amplicon was detected using FRET probes targeting a unique region of ITS1. Quantitation of A. fumigatus DNA was achieved by use of external standards. The presence of PCR inhibitors was determined by use of a unique control plasmid. The analytical sensitivity of the assay was </=10 copies of target DNA. No cross-reactivity occurred with other medically important filamentous fungi. The assay results correlated with pulmonary fungal burden as determined by quantitative culture (r = 0.72, Spearman rank correlation; P </= 0.0001). The mean number of genome equivalents detected in untreated animals was 3.86 log(10) (range, 0.86 to 6.39 log(10)) in tissue. There was a 3.53-log(10) mean reduction of A. fumigatus genome equivalents in animals treated with amphotericin B (AMB) (95% confidence interval, 3.38 to 3.69 log(10); P </= 0.0001), which correlated with the reduction of residual fungal burden in lung tissue measured in terms of log(10) CFU/gram. The enhanced quantitative sensitivity of the real-time PCR assay was evidenced by detection of A. fumigatus genome in infarcted culture-negative lobes, by a greater number of mean genome equivalents compared to the number of CFU per gram in tissue and BAL fluid, and by superior detection of therapeutic response to AMB in BAL fluid compared to culture. This real-time PCR assay using FRET technology is highly sensitive and specific in detecting A. fumigatus DNA from BAL fluid and lung tissue in experimental IPA.

Evaluation of molecular and immunological techniques for the diagnosis of mammary aspergillosis in ewes

Three techniques for the diagnosis of mammary aspergillosis in ewes were compared: indirect ELISA to detect the level of anti-Aspergillus IgG in serum, determination of galactomannan (Platelia procedure), and detection of DNA of Aspergillus in serum by a nested PCR. Twenty sera from proven cases of aspergillosis in ewes were positive using ELISA (100%), 80% were positive using PCR, but only 55% were positive using Platelia. All 20 control sera were negative using ELISA and PCR, whereas using Platelia methodology one was positive and the other doubtful. The detection of antibody by ELISA in sera is therefore a reliable criterion for the diagnosis of mammary aspergillosis in ewes. Platelia showed the same deficiencies reported in humans, with the appearance of false positives and negatives. The use of PCR was promising and might have valuable application in human medicine.

Comparison of real-time PCR, conventional PCR, and galactomannan antigen detection by enzyme-linked immunosorbent assay using bronchoalveolar lavage fluid samples from hematology patients for diagnosis of invasive pulmonary aspergillosis

An iCycler iQ real-time PCR assay targeting 18S rRNA Aspergillus-specific sequences was developed for the diagnosis of invasive pulmonary aspergillosis (IPA). Positive findings were obtained for 18 of 20 (90%) bronchoalveolar lavage (BAL) fluid specimens from patients with probable or confirmed IPA and were obtained for none of the 24 BAL samples from patients with no clinical evidence of aspergillosis. These results were concordant with those of a nested PCR assay, which detected 90% of the patients with IPA, while galactomannan ELISA revealed positivity for 100% of these patients, suggesting that combined use of methods might improve the diagnosis of IPA.

Molecular diagnostics in clinical parasitology and mycology: limits of the current polymerase chain reaction (PCR) assays and interest of the real-time PCR assays

Polymerase chain reaction (PCR) represents a major breakthrough for the diagnosis of infectious diseases. However, the absence of standardized kits for commercially unattractive targets, such as most of the parasites and the fungi, has led to the development of numerous in-house PCR assays. The performances reported, both for the sensitivity and the specificity of these assays are very divergent. For instance, for the antenatal diagnosis of toxoplasmosis, the sensitivity is either 97.4%, or 64%. For the diagnosis of toxoplasmosis in HIV-positive patients, the PCR on blood is either of limited value with a sensitivity of 13% or of excellent yield with a sensitivity of 87.5%. Similar results are reported for the diagnosis of invasive aspergillosis in bone-marrow-transplant recipients. The patients and the clinical specimens tested are often different. This can explain some of the discrepancies. However, when performed, the quality controls on identical specimens show different results depending on the laboratories. An analysis of the PCR techniques used shows that the control of false positive results as a result of carry-over and false negative results owing to PCR inhibitors is far from being systematic. These shortcomings of 'classical' PCR should be solved when real-time PCR assays are developed, leading to some standardization. Automated DNA extraction should also be useful to achieve this goal. Comparison between laboratories should then be possible and regular quality controls will be necessary to ensure the reliability of real-time PCR assays.

Aspergillosis. Pathogenesis, clinical manifestations, and therapy

Diseases caused by Aspergillus species are increasing in importance, especially among immunocompromised hosts. Clinical manifestations are variable, ranging from allergic to invasive disease, largely depending on the status of the host's immune system. This article focuses on the pathogenesis and clinical manifestations of diseases caused by Aspergillus species, with more detailed discussion on therapy of the most morbid manifestation, invasive aspergillosis.

A review of nucleic acid-based diagnostic tests for systemic mycoses with an emphasis on polymerase chain reaction-based assays

Nucleic acid-based assays have good potential to complement and enhance the sensitivity and rapidity of conventional methods used in diagnostic mycology. The majority of molecular tests are polymerase chain reaction (PCR)-based assays focusing mainly on the detection of Candida and Aspergillus spp. from clinical samples. DNA extraction and purification procedures should be standardized and can be facilitated by using commercial extraction kits. In general, protocols that target multi-copy genes provide the greatest sensitivity. Objective endpoint assessments of PCR tests using enzyme-linked immunosorbent assays (ELISA) or commercial quantitative systems are capable of rapidly detecting and identifying Candida and Aspergillus spp. Sequencing of PCR products can be used to confirm the identity of amplicons. In cases of suspected invasive aspergillosis, PCR should be performed on both blood and bronchoalveolar lavage fluid to maximize test sensitivity and the positive predictive value. At least two blood specimens should be tested if PCR is undertaken on blood samples alone. In situ hybridization techniques have been used with success to identify fungi in tissue specimens. The wide application of PCR-based assays relies on the introduction of standardized protocols following their evaluation in multicentre, prospective studies.

Current status of nonculture methods for diagnosis of invasive fungal infections

The incidence of invasive fungal infections has increased dramatically in recent decades, especially among immunocompromised patients. However, the diagnosis of these infections in a timely fashion is often very difficult. Conventional microbiologic and histopathologic approaches generally are neither sensitive nor specific, and they often do not detect invasive fungal infection until late in the course of disease. Since early diagnosis may guide appropriate treatment and prevent mortality, there has been considerable interest in developing nonculture approaches to diagnosing fungal infections. These approaches include detection of specific host immune responses to fungal antigens, detection of specific macromolecular antigens using immunologic reagents, amplification and detection of specific fungal nucleic acid sequences, and detection and quantitation of specific fungal metabolite products. This work reviews the current status and recent developments as well as problems in the design of nonculture diagnostic methods for invasive fungal infections.

Real-time PCR coupled with automated DNA extraction and detection of galactomannan antigen in serum by enzyme-linked immunosorbent assay for diagnosis of invasive aspergillosis

To improve the diagnosis of invasive aspergillosis (IA), we developed a LightCycler PCR assay targeted to Aspergillus fumigatus and A. flavus mitochondrial DNA. To avoid contamination, fully automated nucleic acid extraction with the MagNA Pure LC apparatus was used. The linearity of the results was achieved over a 6-log range of input A. fumigatus DNA, from 0.3 ng to 3 fg/10 microl of water. We retrospectively compared the LightCycler PCR and an enzyme-linked immunosorbent assay for the detection of galactomannan (GM) in serum from 14 patients with IA. The GM assay was more frequently positive (57 of 109; 52%) than the PCR assay (49 of 109; 45%). The LightCycler PCR assay, combined with automated DNA extraction, could be used in association with the GM assay to improve the reliability of IA diagnosis.

Clinical evaluation of a polymerase chain reaction assay to detect Aspergillus species in bronchoalveolar lavage samples of neutropenic patients

The increasing incidence of invasive aspergillosis, a life-threatening infection in immunocompromised patients, emphasizes the need to improve the currently limited diagnostic tools. Using a recently developed two-step polymerase chain reaction (PCR) assay to detect 10 fg of Aspergillus DNA, corresponding to 1-5 colony-forming units (CFU)/ml of spiked samples in vitro, we prospectively examined 197 bronchoalveolar lavage (BAL) samples from 176 subjects, including 141 neutropenic, febrile patients with lung infiltrates, at risk for invasive fungal disease. Underlying diseases of these patients were haematological malignancies; 93 patients suffered from acute leukaemias. Thirty-one of these immunocompromised patients (17.6%) were PCR positive, correlating with positive BAL culture, positive histology from lung surgery or from autopsy, positive computerized tomography scans or positive galactomannan enzyme-linked immunosorbent assay. Six patients (4.3%) of this group had positive PCR results without any correlation to clinical or other diagnostic data, probably owing to contamination of the samples by ubiquitous Aspergillus spores. The samples of two patients (1.4%) with a subsequent histologically proven mould infection were PCR negative. All 102 immunocompromised patients (72.3%) with a negative PCR showed no evidence of invasive fungal disease. From 35 patients without immunodeficiency, four (11.4%) showed positive results, without evidence of invasive or non-invasive pulmonary aspergillosis. In this haematological population, the sensitivity and specificity values of the test reached 93.9% and 94.4%, the positive predictive value 83.8%, the negative predictive value 98.1%. Our data support the considerable clinical value of this PCR assay for confirming and improving diagnosis of pulmonary aspergillosis in high-risk patients.

Quantitative PCR assay to measure Aspergillus fumigatus burden in a murine model of disseminated aspergillosis: demonstration of efficacy of caspofungin acetate

Caspofungin acetate (MK-0991) is an antifungal antibiotic that inhibits the synthesis of 1,3-beta-D-glucan, an essential component of the cell wall of several pathogenic fungi. Caspofungin acetate was recently approved for the treatment of invasive aspergillosis in patients who are refractory to or intolerant of other therapies. The activity of 1,3-beta-D-glucan synthesis inhibitors against Aspergillus fumigatus has been evaluated in animal models of pulmonary or disseminated disease by using prolongation of survival or reduction in tissue CFU as assay endpoints. Because these methods suffer from limited sensitivity or poor correlation with fungal growth, we have developed a quantitative PCR-based (qPCR) (TaqMan) assay to monitor disease progression and measure drug efficacy. A. fumigatus added to naïve, uninfected kidneys as either ungerminated conidia or small germlings yielded a linear qPCR response over at least 4 orders of magnitude. In a murine model of disseminated aspergillosis, a burden of A. fumigatus was detected in each of five different organs at 4 days postinfection by the qPCR assay, and the mean fungal load in these organs was 1.2 to 3.5 log(10) units greater than mean values determined by CFU measurement. When used to monitor disease progression in infected mice, the qPCR assay detected an increase of nearly 4 log(10) conidial equivalents/g of kidney between days 1 and 4 following infection, with a peak fungal burden that coincided with the onset of significant mortality. Traditional CFU methodology detected only a marginal increase in fungal load in the same tissues. In contrast, when mice were infected with Candida albicans, which does not form true mycelia in tissues, quantitation of kidney burden by both qPCR and CFU assays was strongly correlated as the infection progressed. Finally, treatment of mice with induced disseminated aspergillosis with either caspofungin or amphotericin B reduced the A. fumigatus burden in infected kidneys to the limit of detection for the qPCR assay. Because of its much larger dynamic range, the qPCR assay is superior to traditional CFU determination for monitoring the progression of disseminated aspergillosis and evaluating the activity of antifungal antibiotics against A. fumigatus.

Improving efficacy of antifungal therapy by polymerase chain reaction-based strategy among febrile patients with neutropenia and cancer

Early detection of fungal infections in and corresponding early treatment of febrile patients with neutropenia and cancer have been important issues and continue to be major challenges for clinicians. The use of nested PCR to make therapeutic decisions was studied. Sequential blood samples obtained from 42 patients with neutropenia and cancer were tested by nested PCR and culture. Instead of the empirical antifungal therapy strategy, amphotericin B treatment was initiated only for patients who had 2 consecutive positive results by nested PCR. A reduced mortality rate was observed for febrile patients with neutropenia and cancer who had fungal infections. Thus, this strategy, combined with the nested PCR for early detection of fungal infection in febrile patients with neutropenia, may be used as a guideline for antifungal therapy.

Use of real-time PCR on blood samples for diagnosis of invasive aspergillosis

We developed a new quantitative system for diagnosis of invasive pulmonary aspergillosis (IPA) using real-time automated polymerase chain reaction (PCR). Intra-assay and interassay precision rates for in vitro examination were 2.53% and 2.20%, respectively, and the linearity of this assay was obtained when there were >20 copies/well. We examined 323 samples taken from 122 patients with hematological malignancies, including 33 patients with IPA and 89 control patients. Blood samples were subjected to PCR antigen detection methods, using enzyme-linked immunosorbent assay (ELISA) and determination of plasma (1-->3)-beta-D-glucan (BDG) concentration. The sensitivities of PCR, ELISA, and BDG measurement for diagnosis of IPA were 79%, 58%, and 67%, respectively; the specificities were 92%, 97%, and 84%. Positive findings on PCR preceded those of computed tomography by -0.3+/-6.6 days, those of BDG measurement by 6.5+/-4.9 days, and those of ELISA by 2.8+/-4.1 days. Real-time PCR was sensitive for IPA diagnosis, and quantitation was accurate.

Identification of Aspergillus fumigatus and related species by nested PCR targeting ribosomal DNA internal transcribed spacer regions

Aspergillus fumigatus is the most common species that causes invasive aspergillosis. In order to identify A. fumigatus, partial ribosomal DNA (rDNA) from two to six strains of five different Aspergillus species was sequenced. By comparing sequence data from GenBank, we designed specific primer pairs targeting rDNA internal transcribed spacer (ITS) regions of A. fumigatus. A nested PCR method for identification of other A. fumigatus-related species was established by using the primers. To evaluate the specificities and sensitivities of those primers, 24 isolates of A. fumigatus and variants, 8 isolates of Aspergillus nidulans, 7 isolates of Aspergillus flavus and variants, 8 isolates of Aspergillus terreus, 9 isolates of Aspergillus niger, 1 isolate each of Aspergillus parasiticus, Aspergillus penicilloides, Aspergillus versicolor, Aspergillus wangduanlii, Aspergillus qizutongii, Aspergillus beijingensis, and Exophiala dermatitidis, 4 isolates of Candida, 4 isolates of bacteria, and human DNA were used. The nested PCR method specifically identified the A. fumigatus isolates and closely related species and showed a high degree of sensitivity. Additionally, four A. fumigatus strains that were recently isolated from our clinic were correctly identified by this method. Our results demonstrate that these primers are useful for the identification of A. fumigatus and closely related species in culture and suggest further studies for the identification of Aspergillus fumigatus species in clinical specimens.