Aspergillus Polymerase Chain Reaction Research Articles

Clinical Implementation of β-Tubulin Gene-Based Aspergillus Polymerase Chain Reaction for Enhanced Aspergillus Diagnosis in Patients with Hematologic Diseases: A Prospective Observational Study.

The β-tubulin (benA) gene is a promising target for the identification of Aspergillus species. Assessment of the clinical implementation and performance of benA gene-based Aspergillus polymerase chain reaction (PCR) remains warranted. In this study, we assessed the analytical performance of the BenA probe PCR in comparison with the Aspergenius kit. We prospectively collected bronchoalveolar lavage (BAL) fluid via diagnostic bronchoscopy from adult patients with hematologic diseases. BenA gene-based multiplex real-time PCR and sequential melting temperature analysis were performed to detect the azole resistance of Aspergillus fumigatus. In total, 76 BAL fluids in 75 patients suspicious of invasive pulmonary aspergillosis (IPA) were collected. Before the application of PCR, the prevalence of proven and probable IPA was 32.9%. However, after implementing the benA gene-based PCR, 15.8% (12 out of 76) of potential IPA cases were reclassified as probable IPA. The analytical performance of the BenA probe PCR in BAL samples was comparable to that of the Aspergenius kit. The diagnostic performance was as follows: sensitivity, 52.0%; specificity, 64.7%; positive predictive value, 41.9%; negative predictive value, 73.3%; positive likelihood ratio, 1.473; and negative likelihood ratio, 0.741. Moreover, benA gene-based Aspergillus PCR discriminated all major sections of Aspergillus, including cryptic species such as Aspergillus tubingensis. Sequential melting temperature analysis successfully detected 2 isolates (15.4%) of A. fumigatus carrying resistant mutations. BenA gene-based Aspergillus PCR with melting temperature analysis enhances diagnostic accuracy and detects not only cryptic species but also resistant mutations of A. fumigatus. It shows promise for clinical applications in the diagnosis of IPA.

Culture-independent diagnostic approaches for invasive aspergillosis in solid organ transplant recipients.

Prompt and accurate diagnosis of invasive aspergillosis (IA) is crucial for immunocompromised patients, including those who have received a solid organ transplant (SOT). Despite their low sensitivity, microscopic detection and conventional culture are considered the 'gold standard' methods. In conjunction with conventional culture, culture-independent assays such as serum galactomannan testing and Aspergillus polymerase chain reaction (PCR) have been incorporated into the diagnostic process for IA. The recently revised consensus definitions from the European Organization for Research and Treatment of Cancer and the Mycosis Study Group have adjusted the threshold for positive galactomannan testing based on the sample type, and have excluded 1,3-β-D-glucan testing as a mycological criterion. Following extensive standardization efforts, positive Aspergillus PCR tests using serum, plasma, or bronchoalveolar lavage fluid have been added. However, there are limited studies evaluating the clinical utility of these culture-independent assays for the early diagnosis of IA in SOT recipients. Therefore, further research is required to determine whether these assays could aid in the early diagnosis of IA in SOT recipients, particularly in relation to the organ transplanted. In this review, we examine the culture-independent diagnostic methods for IA in SOT recipients, as well as the clinical utility of these assays.

An Overview of Systematic Reviews of Polymerase Chain Reaction (PCR) for the Diagnosis of Invasive Aspergillosis in Immunocompromised People: A Report of the Fungal PCR Initiative (FPCRI)-An ISHAM Working Group.

This overview of reviews (i.e., an umbrella review) is designed to reappraise the validity of systematic reviews (SRs) and meta-analyses related to the performance of Aspergillus PCR tests for the diagnosis of invasive aspergillosis in immunocompromised patients. The methodological quality of the SRs was assessed using the AMSTAR-2 checklist; the quality of the evidence (QOE) within each SR was appraised following the GRADE approach. Eight out of 12 SRs were evaluated for qualitative and quantitative assessment. Five SRs evaluated Aspergillus PCR on bronchoalveolar lavage fluid (BAL) and three on blood specimens. The eight SRs included 167 overlapping reports (59 evaluating PCR in blood specimens, and 108 in BAL), based on 107 individual primary studies (98 trials with a cohort design, and 19 with a case-control design). In BAL specimens, the mean sensitivity and specificity ranged from 0.57 to 0.91, and from 0.92 to 0.97, respectively (QOE: very low to low). In blood specimens (whole blood or serum), the mean sensitivity ranged from 0.57 to 0.84, and the mean specificity from 0.58 to 0.95 (QOE: low to moderate). Across studies, only a low proportion of AMSTAR-2 critical domains were unmet (1.8%), demonstrating a high quality of methodological assessment. Conclusions. Based on the overall methodological assessment of the reviews included, on average we can have high confidence in the quality of results generated by the SRs.

A case-control study of the effects of Aspergillus clinical phenotypes on pulmonary functions in patients with cystic fibrosis.

There are no precise data about the effect of Aspergillus infection on lung function other than allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis (pwCF). Here, we aimed to determine clinical phenotypes caused by Aspergillus spp. using laboratory and immunologic parameters and to compare Aspergillus phenotypes in terms of pulmonary function tests (PFT) prospectively. Twenty-three pwCF who had Aspergillus isolation from respiratory cultures in the last year (case group) and 20 pwCF without Aspergillus isolation in sputum (control group) were included. Aspergillus immunoglobulin (Ig)-G, Aspergillus IgE, Aspergillus polymerase chain reaction(PCR), galactomannan, total IgE from blood samples, and Aspergillus PCR and galactomannan from sputum, and skin prick test reactivity to Aspergillus antigen were used to distinguish different Aspergillus phenotypes. Pulmonary functions and frequency of pulmonary exacerbations were evaluated during a 1-year follow-up. Of 23 pwCF, 11 (47.8%) had Aspergillus colonization, nine (39.1%) had Aspergillus bronchitis, and three (13%) had ABPA. Aspergillus infection was not associated with worse z-scores of forced expiratory volume in the first second (FEV1) (p = 0.612), forced vital capacity (p = 0.939), and the median FEV 1% decline (0.0%/year vs. -4.7%/year, p = 0.626). The frequency of pulmonary exacerbations in the Aspergillus infected and noninfected groups was similar. Although Aspergillus spp. Isolation in pwCF was not associated with decreased lung function, a further decline was seen in the ABPA subgroup, and frequent pulmonary exacerbations during the 1-year follow-up.

Evaluation of the Diagnostic Accuracy and Clinical Utility of Fungal Profile Plus Polymerase Chain Reaction Assay in Pulmonary Infections.

Pulmonary infections due to Aspergillus, Mucorales, and Nocardia have high morbidity and mortality, in part due to diagnostic challenges. Commercially available molecular assays on bronchoalveolar lavage fluid (BALF) may have increased sensitivity over currently available diagnostic options. Our aim was to characterize the diagnostic performance of assays for each of these pathogens in our patient population. The medical records of patients whose BALF was tested by polymerase chain reaction (PCR) for Aspergillus, Mucorales, and Nocardia between 2019 and 2021 were reviewed in a cross-sectional manner. European Organization for Research and Treatment of Cancer and the Mycoses Study Group (EORTC/MSG) definitions of "proven," "probable," and "possible" infection were used, including histopathology, serology, and culture. We used (1) "proven" or "probable" infection by EORTC criteria, (2) improvement or stabilization on targeted antimicrobial therapy, and (3) absence of a more likely diagnosis as the reference standard. The Aspergillus PCR assay demonstrated the highest agreement with the diagnostic reference standard, with 31.25% (10/32) sensitivity and 97.17% (206/212) specificity. Positive and negative predictive values were 62.50% (10/16) and 90.35% (206/228), respectively. No Mucorales or Nocardia infections were identified by the diagnostic reference standard, so the sensitivity could not be calculated. The specificity of Mucorales and Nocardia targets was 98.35% and 96.69%, respectively. Our data demonstrated relatively poor clinical sensitivity for all 3 constituent PCR assays in our patient population, suggesting a limited role for this test in the diagnosis of Aspergillus, Mucorales, or Nocardia.

P474 The value of PCR-based azole resistance detection in invasive aspergillosis: A prospective multicenter study

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectivesPrompt detection of azole-resistant Aspergillus fumigatus will result in the timely start of active treatment and may improve the survival of invasive aspergillosis (IA). The use of a multiplex polymerase chain reaction (PCR) targeting Aspergillus species and fumigatus DNA as well as the two most prevalent azole resistance- associated mutations (RAMs) in the cyp51A gen (TR34/L98H and TR46/Y121F/T289A) could shorten the time to detect azole-resistant IA.MethodsIn a prospective study in 12 Dutch and Belgian centers, we evaluated the clinical value of the multiplex AsperGenius®PCR in hematology patients with a pulmonary infiltrate undergoing bronchoalveolar lavage (BALf) sampling. The primary endpoint was antifungal treatment failure in the 6 weeks after antifungal treatment initiation in the patients in which azole-resistant IA was detected. Treatment failure was defined as death or a switch to an antifungal agent from another class after at least 5 days of first-line therapy. Patients with a mixed azole-susceptible/resistant infection were excluded from this analysis to ascertain that the infection was indeed caused by the resistant strain.ResultsOf 323 patients enrolled, sufficient BALf for PCR testing remained in 299. Probable fungal disease was diagnosed in 95 (34%), Aspergillus cultured in 24 (8%), Aspergillus DNA detected in 118 (39%), and A. fumigatus DNA in 88 (29%) patients. The resistance PCR was conclusive in 54/88 (61%) and RAMs were detected in 8 (15%), Table 1. All 8 had probable IA but 2 had a mixed infection and were excluded. In the 6 remaining patients, treatment failure was observed in one. Compared with the GM negative patients and despite antifungal therapy, a positive GM test was associated with a 13% higher 6-week overall mortality (P = .01), Table 2. Surprisingly, the 6-week mortality in the 65 patients who had a positive Aspergillus PCR but a negative GM and culture was not increased compared to those with a negative PCR (PCR + 14% vs. PCR- 16% mortality, P = .68).ConclusionsIn patients with an underlying hematological disease and a pulmonary infiltrate, the detection of Aspergillus DNA by PCR on BALf was not associated with increased mortality. The exact place of the Aspergillus PCR in the EORTC-MSGERC invasive fungal infection criteria is therefore uncertain. In 15% of the patients in whom A. fumigatus DNA was present, azole RAMs were detected by PCR. In only 1/6 probable cases of IA with RAMs detected, antifungal treatment failure was observed. Basing the choice of antifungal therapy on the result of a cyp51a resistance PCR may help to reduce the impact of azole resistance on mortality.

Real-World Financial and Clinical Impact of Diagnostic-Driven and Empirical-Treatment Strategies in High-Risk Immunocompromised Patients with Suspected Aspergillus Infection in the United Kingdom.

ABSTRACTA diagnostic-driven (DD) treatment strategy has proven successful for treating invasive fungal infections (IFIs) caused by Aspergillus. However, uptake of this treatment strategy is not fully embraced. This study compares the economic and clinical impact of DD and empirical-treatment (ET) strategies used within hospitals. Methods: a decision-analytic model was developed to compare costs and clinical outcomes associated with ET or a DD strategy of identifying infections caused by Aspergillus via galactomannan-antigen testing or Aspergillus polymerase chain reaction (PCR) in neutropenic patients with unexplained fever. Patients were treated prophylactically with antifungal treatments as seen in United Kingdom (UK) hospitals. The IFI incidence, response, mortality, resource use, and adverse events were obtained from meta-analyses and other clinical studies. Analyses were performed from the U.K. hospital perspective, and costs were obtained from standard costing sources. Although diagnostic-testing costs increased, total cost and length of stay were reduced by £1,121 and 1.54 days when treating via a DD strategy. Intensive care and general ward days accounted for > 40% of total costs and > 58% of the cost reduction came from reduced antifungal costs. Treating with a DD strategy reduced the number of patients being treated with antifungal agents while survival was increased. Thus, a DD strategy was cost savings (-£136,787 cost per death avoided) compared with an ET strategy. Conclusion: this study suggests that incorporating a DD strategy as the preferred treatment protocol may be a cost-saving and clinically improved treatment strategy for managing neutropenic patients with unexplained fever.IMPORTANCE Patients at risk of invasive fungal infections (IFIs), such as Aspergillus spp., tend to be immunocompromised and usually take several medications which may generate many side effects. Prescribing is further complicated by comorbidities, drug interactions and challenges accessing diagnostics. Therefore, adding another agent may be neither straightforward nor the best option for these types of patients. A diagnostic-driven (DD) treatment strategy has proven successful for treating IFIs. However, uptake of this treatment strategy is not fully embraced in clinical practice perhaps because this strategy is thought to be more costly and/or to result in higher mortality relative to treating empirically. We developed a decision-analytic model to examine the impact of these 2 strategies on costs and health outcomes. This study indicates that incorporating a DD strategy as the preferred treatment protocol may be a cost-saving and clinically improved treatment strategy for managing neutropenic patients with unexplained fever.

Introducing 1,3‐beta‐d‐glucan for screening and diagnosis of invasive fungal diseases in Australian high‐risk haematology patients: is there a clinical benefit?

Early, accurate diagnosis of invasive fungal disease (IFD) improves clinical outcomes. 1,3-beta-d-glucan (BDG) (Fungitell, Associates of Cape Cod, Inc., Falmouth, MA, USA) detection can improve IFD diagnosis but has been unavailable in Australia. To assess performance of serum BDG for IFD diagnosis in a high-risk Australian haematology population. We compared the diagnostic value of weekly screening of serum BDG with screening by Aspergillus polymerase chain reaction and Aspergillus galactomannan in 57 at-risk episodes for the diagnosis of IFD (proven, probable, possible IFD). IFD episodes were: proven (n = 4); probable (n = 4); possible (n = 18); and no IFD (n = 31). Using two consecutive BDG results of ≥80 pg/mL to call a result 'positive', the sensitivity, specificity, positive predictive value and negative predictive value was 37.5%, 64.5%, 23.1% and 80.7% respectively. For invasive aspergillosis, test performance increased to 50%, 90.3%, 57.1% and 87.5% respectively if any two of serum BDG/Aspergillus polymerase chain reaction/galactomannan yielded a 'positive' result. In proven/probable IFD, five of eight episodes returned a positive BDG result earlier (mean 6.6 days) than other diagnostic tests. False-negative BDG results occurred in three of eight episodes of proven/probable IFD, and false positive in 10 of 31 patients with no IFD. Erratic patterns of BDG values predicted false positive results (P = 0.03). Using serum BDG results, possible IFD were reassigned to either 'no' or 'probable' IFD in 44% cases. Empiric anti-fungal therapy use may have been optimised by BDG monitoring in 38.5% of courses. The BDG assay can add diagnostic speed and value but was hampered by low sensitivity and positive predictive value in Australian haematology patients.

Hemophagocytic Lymphohistiocytosis and Severe Hypoxemia in a Preterm Infant.

Hemophagocytic Lymphohistiocytosis and Severe Hypoxemia in a Preterm Infant.

Evaluation of Serum Mucorales Polymerase Chain Reaction (PCR) for the Diagnosis of Mucormycoses: The MODIMUCOR Prospective Trial.

Early diagnosis and prompt initiation of specific antifungal treatment are essential for improving the prognosis of mucormycosis. We aimed to assess the performance of serum Mucorales quantitative polymerase chain reaction (qPCR) for the early diagnosis and follow-up of mucormycosis. We prospectively enrolled 232 patients with suspicion of invasive mold disease, evaluated using standard imaging and mycological procedures. Thirteen additional patients with proven or probable mucormycosis were included to analyze DNA load kinetics. Serum samples were collected twice-a-week for Mucorales qPCR tests targeting the Mucorales genera Lichtheimia, Rhizomucor, and Mucor/Rhizopus. The sensitivity was 85.2%, specificity 89.8%, and positive and negative likelihood ratios 8.3 and 0.17, respectively in this prospective study. The first Mucorales qPCR-positive serum was observed a median of 4 days (interquartile range [IQR], 0-9) before sampling of the first mycological or histological positive specimen and a median of one day (IQR, -2 to 6) before the first imaging was performed. Negativity of Mucorales qPCR within seven days after liposomal-amphotericin B initiation was associated with an 85% lower 30-day mortality rate (adjusted hazard ratio = 0·15, 95% confidence interval [.03-.73], P = .02). Our study argues for the inclusion of qPCR for the detection of circulating Mucorales DNA for mucormycosis diagnosis and follow-up after treatment initiation. Positive results should be added to the criteria for the consensual definitions from the European Organization for the Research and Treatment of Cancer/Mycoses Study Group Education and Research Consortium (EORTC/MSGERC), as already done for Aspergillus PCR.

Invasive pulmonary aspergillosis in critically ill patients with COVID-19 in Australia: implications for screening and treatment.

We report four cases of invasive pulmonary aspergillus co-infection in patients with coronavirus disease 2019 (COVID-19) infection and acute respiratory distress syndrome requiring intensive care unit (ICU) admission. Aspergillus fumigatus and Aspergillus terreus were isolated, with early infection onset following ICU admission. Clinicians should be aware of invasive pulmonary aspergillosis in ICU patients with COVID-19 infection, particularly those receiving dexamethasone. We propose screening of these high-risk patients with twice-weekly fungal culture from tracheal aspirate and, if feasible, Aspergillus polymerase chain reaction. Diagnosis is challenging and antifungal treatment should be considered in critically ill patients who have new or worsening pulmonary changes on chest imaging and mycological evidence of infection.

Diagnosing pulmonary aspergillosis is much easier than it used to be: a new diagnostic landscape.

Significant innovations in the past decade have resulted in more sensitive and faster diagnosis of allergic, chronic and invasive pulmonary aspergillosis, as well as Aspergillus bronchitis and Aspergillus nodules. This new diagnostic landscape has revealed that the incidence and prevalence of aspergillosis is substantially higher than previously understood, and is summarised in this review. Oral and intravenous antifungal treatment offers good clinical response rates for affected patients. Nevertheless, missed diagnoses mean that patients are over-treated with antibacterial agents, corticosteroids and anti-TB drugs, resulting in continuing illness and often death. The clinical introduction of several high performing diagnostic tests is helping to redefine patient management. It is well-known that Aspergillus antigen can be detected in 70-95% of bronchoscopy samples in patients with invasive and chronic aspergillosis in less than 1 hour. Aspergillus immunoglobulin G (IgG) (precipitins) is >90% sensitive and >85% specific for chronic and allergic aspergillosis. High-volume respiratory fungal culture and Aspergillus polymerase chain reaction have 3-5-fold higher sensitivity than routine bacterial culture. Aspergillus IgE (or skin prick testing) diagnoses Aspergillus sensitisation in asthma, cystic fibrosis, chronic obstructive pulmonary disease and post-TB, and correlates well with poorer lung function and/or exacerbations. Clinicians and laboratorians across the world need to mainstream these excellent new tools to improve clinical outcomes by delivering results in a more timely and accurate fashion.

The screening of blood by Aspergillus PCR and galactomannan ELISA precedes BAL detection in patients with proven and probable IA.

Early detection of Aspergillus infection has the potential to facilitate a more effective management of invasive disease. Data from probable/proven cases of invasive aspergillosis (IA) with a positive galactomannan enzyme-linked immunosorbent assay (GM) bronchoalveolar lavage fluid (BALF) was analyzed in respect to serum GM and/or polymerase chain reaction (PCR) screening of blood samples prior to, or concurrent with bronchoscopy. Concurrent serum GM testing is less sensitive than BALF itself. Nevertheless screening of blood using GM or PCR testing detected IA cases earlier (GM: 42% or PCR: 56%), particularly when combined (GM/PCR: 73%). Therefore, regular screening facilitates and improves early detection of IA in patients suffering from acute leukemia.

Positive Aspergillus PCR as a marker of azole resistance or sub-therapeutic antifungal therapy in patients with chronic pulmonary aspergillosis.

Chronic pulmonary aspergillosis (CPA) is a progressive respiratory disease, caused most commonly by A fumigatus, with significant morbidity and mortality. Azole resistance in A fumigatus is a growing concern worldwide, with resistance to itraconazole reported in up to 50% of patients. The aim of this study was to determine whether a positive Aspergillus PCR (polymerase chain reaction) is a marker of resistance in CPA patients on azole therapy. Patients were selected via a consecutive database search for the first 50 CPA patients with a positive Aspergillus PCR from January to September 2016. Data were collected regarding concurrent and subsequent culture results, current therapy and serum antifungal levels. PCR-positive patients not on therapy were included as the control group. Twenty-three patients were on therapy (15 itraconazole, 4 voriconazole and 4 posaconazole). Cycle threshold (Ct) values ranged from 20.8 to 37.9; no significant difference was found between each treatment and the control group (P=.47). In treated patients, concurrent azole-resistant A fumigatus was found in 75% of A fumigatus-positive cultures (6/8). All of the resistant isolates in the itraconazole group showed therapy resistance. Twenty per cent of all itraconazole levels were sub-therapeutic. No significant difference was found in serum itraconazole levels for patients on itraconazole with a positive PCR versus negative PCR (P=.44). Positive sputum, Aspergillus-specific PCR can be associated with azole resistance in CPA patients on therapy.

Blood Aspergillus PCR: The Good, the Bad, and the Ugly.

Invasive Aspergillosis (IA) is one of the most common invasive fungal diseases and is accompanied by high morbidity and mortality. In order to maximize patient outcomes and survival, early and rapid diagnosis has been shown to be pivotal. Hence, diagnostic tools aiding and improving the diagnostic process are ambitiously searched for. In this context, polymerase chain reaction (PCR) may represent a potential candidate. Its additional value and benefits in diagnosis have been demonstrated and are scientifically established. Nevertheless, standardized and widespread usage is sparse because several factors influence diagnostic quality and need to be considered in order to optimize diagnostic performance and outcome. In the following review, the current role of PCR in the diagnosis of IA is explored, with special focus on the strengths and limitations of PCR in different settings.

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.

Invasive Fungal Infections in the Pediatric Intensive Care Unit.

Invasive Fungal Infections in the Pediatric Intensive Care Unit.

968. Managing Invasive Aspergillosis in the Era of Diagnostic PCR and Increasing Triazole Resistance: A Modeling Study of Different Strategies

BackgroundTriazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive Aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance on a genetic level, which opened up new possibilities for targeted therapy. In the absence of clinical trials, a modeling study delivers estimates of the added value of resistance detection with PCR and which empiric therapy would be optimal when local resistance rates are known.MethodsWe performed a decision-analytic modeling study based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. We compared 6 clinical strategies that differ in the use of PCR diagnostics (A: not used, B: used) and in empiric therapeutic choice in case of unknown triazole susceptibility: Voriconazole (1, VOR), Liposomal Amphotericin B (2, LAmB), or both (3). Outcome measures were proportion of correct treatment, survival, and serious adverse events.ResultsImplementing Aspergillus PCR tests was projected to result in residual treatment susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using VOR). Empiric LAmB outperformed VOR at resistance rates higher than 5–20%, depending on PCR use and estimated survival benefits of VOR over LAmB (Figure 1). Combination therapy of VOR and LAmB performed best at all resistance rates but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events (Figure 2). The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole-resistance rates.ConclusionIntroduction of current Aspergillus PCR tests on BAL-fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and of adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR, and individual patient characteristics. Disclosures All authors: No reported disclosures.

Managing invasive aspergillosis in haematological patients in the era of resistance polymerase chain reaction and increasing triazole resistance: A modelling study of different strategies

Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known. A decision-analytic modelling study was performed based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. Six clinical strategies were compared that differ in use of PCR diagnostics (used vs not used) and in empiric therapeutic choice in case of unknown triazole susceptibility: voriconazole, liposomal amphotericin B (LAmB) or both. Outcome measures were proportion of correct treatment, survival and serious adverse events. Implementing aspergillus PCR tests was projected to result in residual treatment-susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using voriconazole). Empiric LAmB outperformed voriconazole at resistance rates >5-20%, depending on PCR use and estimated survival benefits of voriconazole over LAmB. Combination therapy of voriconazole and LAmB performed best at all resistance rates, but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events. The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole resistance rates. Introduction of current aspergillus PCR tests on BAL fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR and individual patient characteristics.

Diagnosis of aspergillosis by PCR: Clinical considerations and technical tips.

Standardization of Aspergillus polymerase chain reaction (PCR) protocols has progressed, and analytical validity of blood-based assays has been formally established. It remains necessary to consider how the tests can be used in practice to maximize clinical utility. To determine the optimal diagnostic strategies and influence on patient management, several factors require consideration, including the patient population, incidence of invasive aspergillosis (and other fungal disease), and the local antifungal prescribing policy. Technical issues such as specimen type, ease of sampling, frequency of testing, access to testing centers, and time to reporting will also influence the use of PCR in clinical practice. Interpretation of all diagnostic tests is dependent on the clinical context and molecular assays are no exception, but with the proposal to incorporate Aspergillus PCR into the second revision of the consensus guidelines for defining invasive fungal disease the acceptance and understanding of molecular tests should improve.