Diagnosis Of Invasive Aspergillosis In Patients Research Articles

The Aspergillus Lateral Flow Assay for the Diagnosis of Invasive Aspergillosis: an Update.

Purpose of ReviewTo review the data on the Aspergillus lateral flow assay for the diagnosis of invasive Aspergillosis.Recent FindingsAspergillus spp. cause a wide spectrum of disease with invasive aspergillosis (IA) as its most severe manifestation. Early and reliable diagnosis of disease is crucial to decrease associated morbidity and mortality, and enable prompt initiation of treatment for IA. Most recently, non-culture-based tests, such as Aspergillus galactomannan (GM), have been useful in early identification and treatment of patients with IA. However, cost, turnaround time, and variable performance indifferent populations at risk for IA remain significant drawbacks to the use of this test. Several diagnostic tests for IA have been developed, including the sōna Aspergillus GM Lateral flow assay (GM-LFA) rapid test.SummaryThe GM-LFA has shown excellent performance for the diagnosis of IA in patients with hematologic malignancy and may be a viable option for settings where ELISA GM testing is not feasible. Further evaluation of the GM-LFA in the non-hematology setting is ongoing, including in solid organ transplant recipients and patients in the intensive care unit.

Evaluation of Commercially Available Real-Time Polymerase Chain Reaction Assays for the Diagnosis of Invasive Aspergillosis in Patients with Haematological Malignancies.

Early diagnosis of invasive aspergillosis (IA) is a challenge. Non-specific clinical and radiologic findings, as well as difficulties in conventional diagnostic method application, may delay correct diagnosis. Nowadays, nucleic acid-based assays have reduced the need for conventional antigen detection and culture-based methods and provided new opportunities for patient care. Aspergillus PCR is now included in the latest European Cancer Research and Treatment Organization/Mycosis Study Group definition updates. We evaluated the performance of commercial real-time polymerase chain reaction (PCR) MycAssay Aspergillus PCR and Artus Aspergillus RG PCR assays and compared the results with galactomannan enzyme immunoassay. During 41 febrile neutropenic episodes, 168 serum samples were collected from 32 patients with haematological malignancies. IA diagnosis was established according to the revised guidelines of the European Organization for Research and Treatment of Cancer/Mycoses Study Group. Twenty-one probable episodes were identified. There were no proven IA cases in the study. In 20 episodes, patients did not fulfil the established criteria for the IA diagnosis. Artus Aspergillus RG PCR assay had a sensitivity of 47.6% and specificity of 100%, while those of MycAssay Aspergillus PCR were 61.9% and 100%, respectively. Two different PCR assays were used in this study. Although there are many studies that evaluated MycAssay Aspergillus PCR, data regarding Artus Aspergillus RG PCR assay are scarce. We found moderate sensitivity and high specificity in the diagnosis of IA in patients with haematological malignancy in both PCR methods. Our results demonstrated that commercial PCR assays can be applied for the early diagnosis and pre-emptive treatment of IA.

Role of Aspergillus Galactomannan Antigen Test for the Screening of Invasive Aspergillosis in Patients with Hematological Malignancies

Background: Invasive aspergillosis (IA) is a leading cause of death among immunocompromised patients, particularly those with hematological malignancies. The use of galactomannan (GM) antigen as a biological marker for screening of IA in high-risk patients is attractive and non-invasive tool that detect evidence of IA prior to the appearance of clinical manifestations.
 Objectives: The aim of this study was to compare the diagnostic value of the conventional blood culture technique to the serological detection of GM antigen using ELISA for screening of IA in neutropenic patients with hematological malignancies.
 Methods: Forty patients with haematological malignancies from those admitted to the Clinical Oncology Department of Menoufia University Hospitals (MUH) were enrolled and classified to have either proven (5/40; 12.5%), probable (10/40; 25%) or possible (25/40; 62.5%) invasive aspergillosis based on the clinical criteria provided by the European Organization for research and treatment of Cancer (EORTC) and Mycoses Study Group (MSG). Blood samples were collected from all participants and subjected to conventional blood culture for isolation and identification of Aspergillus spp. ELISA technique was applied for serological detection of GM antigen in the patients’ serum samples.
 Results: The sensitivity, specificity, PPV(positive predictive value) and NPV (negative predictive value of GM antigen ELISA testing were 100%, 74%, 36% and 100% respectively for both proven and probable cases. On applying the principle of test in series (the patient is positive if positive in both culture and the GM test), the results were improved to 100% sensitivity, 100% specificity, 100% PPV, 100% NPV and 100% accuracy. Galactomannan antigen testing proved excellent sensitivity (80%) compared to other clinical features and radiological criteria for diagnosis of probable aspergillosis and proved to be a good negative test.
 Conclusion: With conjunction of clinical and radiological signs, Aspergillus GM test can assist physicians in the of diagnosis of IA in patients with hematological malignancies to allow initiation of effective antifungal therapy which is ultimately important in high-risk populations.

Evaluation of Serum Galactomannan Enzyme Immunoassay at Two Different Cut-offs for the Diagnosis of Invasive Aspergillosis in Patients with Febrile Neutropenia

Background: Invasive aspergillosis (IA) is an increasingly common and fatal opportunistic fungal infection in patients with haematological diseases. Early diagnosis is difficult as mycological culture techniques have low sensitivity and the radiological tools have low specificity. Galactomannan enzyme immunoassay (GEI) detects galactomannan in the human serum with a reported sensitivity and specificity between 30% and 100%. Aims: The aim of this study was to analyse the role of GEI in diagnosis of IA in patients with febrile neutropenia and to evaluate the role of GEI in the diagnosis of IA as per the revised (2008) European Organization for Research and Treatment of Cancer–Mycoses Study Group (EORTC–MSG) criteria at two different optical density (OD) cut-offs of 0.5 and 1.0. Setting: This prospective study was conducted in Safdarjung Hospital, New Delhi, India. Methods: GEI testing was performed in adult patients of febrile neutropenia with evidence of IA. Results at two different OD indices (ODIs) of 0.5 and 1.0 were analysed. The evaluation of the diagnostic parameter, that is, GEI was measured in terms of sensitivity, specificity and positive and negative predictive value and was validated with the revised (2008) EORTC–MSG diagnostic criteria of IA. Results: One hundred and eleven patients had evidence of IA, of which 79 patients were GEI positive when cut-off ODI was 0.5, whereas with cut-off ODI 1.0, 55 patients were GEI positive. Conclusion: ODI of 1.0 should be considered as positive while in patients with OD between 0.5 and 1.0, repeat sampling from the patient is recommended.

Clinical risk factors and bronchoscopic features of invasive aspergillosis in intensive care unit patients.

Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunocompromised patients. During recent years, a rising incidence of IA in Intensive Care Unit (ICU) patients has been reported. The patterns of IA related infection may differ according to the type of underlying disease. Unfortunately little is known about the characteristics of IA in ICU patients. In the present study we assessed IA related clinical and bronchoscopy findings in ICU patients. This study was performed at the ICU units in Sari and Babul, Mazandaran from August 2009 through September 2010. We analysed 43 ICU patients with underlying predisposing conditions for IA. Bronchoalveolar lavage (BAL) samples were collected by bronchoscope twice a weekly. The samples were analyzed by direct microscopic examination, culture and non-culture based diagnostic methods. Patients were assigned a probable or possible diagnosis of IA according to the consensus definition of the EORTC/MSG. Out of 43 suspected patients to IA, 13 (36.1%) cases showed IA. According to criteria presented by EORTC/MSG, they were categorized as: 4 cases (30.8%) of possible IA and 9 (69.2%) of probable IA. The observed mortality was 69.2%. The main underlying predisposing conditions were neutropenia, hematologic malignancy, and COPD. The macroscopic finding in bronchoscopy included of Prulent secretion (46.6%), Mucosal bleeding (30.7%), Mucosal erythema (23%), Trachobronchomalasia (15.3%). The diagnosis of IA in patients with critical illness in ICU is even more difficult. The clinical diagnostic process is often dependent on indirect circumstantial data enhancing the probability of IA. Bronchoscopy with inspection of the tracheobronchial tree, sampling of deep airway secretions and BAL can be helpful.

Diagnosis of invasive aspergillosis using Galactomannan assay in pediatric patients with cancer

20522 Background: Invasive aspergillosis (IA) is an important cause of increased mortality and morbidity in immunocompromised patients. Early diagnosis is difficult as microbiological culture techniques have low sensitivity and the radiological tools have low specificity. Some adult studies have concluded that serial determination of Galactomannan by sandwich Elisa (GM Assay) is a sensitive tool for the diagnosis of IA in patients at risk. Due to the paucity of data in the pediatric age group we evaluated utility of GM Assay in diagnosis of IA in pediatric cancer patients. Methods: This is a prospective study, which included high-risk pediatric cancer patients admitted with fever at Sir Ganga Ram Hospital from Oct 2006 to Dec 2007. They were receiving chemotherapy for malignancy with neutropenia <500 neutrophils/mm3 for >10 days, bone marrow transplant - allogeneic/autologous, relapsed acute lymphoblastic leukemia and acute myeloid leukemia. GM assay was done twice weekly in each episode. GM assay index >1.0 was taken as positive. CT chest/sinus and Broncho-alveolar lavage (BAL) was performed as per protocol. IA was classified as Proven, Probable, Possible and No fungus as per EORTC Guidelines. Results: A total of 95 serum samples for GM Assay were collected during 34 episodes of fever (Febrile neutropenia - 23 episodes). 34/95 (36%) GM assay serum samples were positive. 4 had proven IA, 6 had Probable IA, 3 had Possible IA and 21 had No fungus as per EORTC guidelines. 11 patients had evidence of suspected IA in CT Chest. BAL was done in 6 episodes, out of which 2 episodes had evidence of Aspergillus. The GM Assay conducted in this study had a sensitivity of 90% and specificity of 80%. It had a positive predictive value of 64% and negative predictive value of 95%. GM assay was negative in 2 episodes where Piperacillin-Tazobatum was used. Conclusion: Serial GM Assay is highly sensitive for diagnosis of IA in high-risk pediatric cancer patients. This test has a good negative predictive value in ruling out IA in immunosuppressed children. Results of GM Assay of episodes with Proven, Probable, Possible and No IA Patient case category Positive GM Negative GM Total episodes Proven IA 3 1 4 Probable IA 6 0 6 Possible IA 2 1 3 No Fungus 2 19 21 Total 13 21 34 No significant financial relationships to disclose.

Aspergillus galactomannan testing in patients with long-term neutropenia: implications for clinical management

We carried out a prospective study on galactomannan enzyme immuno assay (GEI) (Platelia™ Aspergillus EIA, Bio-Rad) testing for diagnosis of invasive aspergillosis (IA) in serum and broncho-alveolar lavage (BAL) in 200 patients with hematological malignancies and profound neutropenia. The incidence of proven and probable IA was 6% and 5.5%, respectively. In patients with fever or pneumonia, a single-positive GEI test result (galactomannan index≥0.5) had excellent specificity (100%). Sensitivity was relatively low (40%) at onset of fever, but increased to 94.7% after 6 days of fever. In patients with infiltrates in chest X-ray or computed tomography scan (n=48), GEI testing in BAL had a favorable diagnostic accuracy as compared with GEI testing in serum (sensitivity100% versus 71%). Our findings indicate that antifungal therapy should be started immediately at onset of fever in neutropenic patients with positive GEI tests. In patients with fever refractory to broad-spectrum antibiotics (≥6 days of fever), the high diagnostic accuracy makes GEI testing a valuable diagnostic tool and questions the common strategy to carry out antifungal treatment irrespective of diagnostic testing in this situation. Our data also show that GEI testing in BAL can be useful for early diagnosis of IA in patients with hematological malignancies and pulmonary infiltrates.

A comparison of galactomannan-ELISA and a newly developed galactomannan-LATEX test in the serologic diagnosis of invasive aspergillosis in patients with hematologic malignancies

We compared the sensitivity and specificity of galactomannan enzyme-linked immunosorbent assay (GM-ELISA) with that of a newly developed version of the commercially available latex agglutination test (GM-LATEX) in our patient population. Serum samples were collected from 144 healthy adult donors (controls); another 17 consecutive hematologic malignancy (HM) patients with probable or proven invasive aspergillosis (IA) were tested. Clinical, microbiological, and pathological data were obtained. The sensitivity of the GM-LATEX test was 53% per patient and 66% per sample and that of the GM-ELISA test was 41% per patient and 21% per sample. Both tests demonstrated a specificity of 99%. The GM-LATEX test demonstrated a superior sensitivity in terms of detecting galactomannan and thus may be useful in the diagnosis of IA in patients with HM.