Using staged tree models for health data: Investigating invasive fungal infections by aspergillus and other filamentous fungi

Machine learning models are increasingly used in the medical domain to study the association between risk factors and diseases to support practitioners in understanding health outcomes. In this paper, we showcase the use of machine-learned staged tree models for investigating complex asymmetric dependence structures in health data. Staged trees are a specific class of generative, probabilistic graphical models that formally model asymmetric conditional independence and non-regular sample spaces. An investigation of the risk factors in invasive fungal infections demonstrates the insights staged trees provide to support medical decision-making.

Lung and sinus fungal infection imaging in immunocompromised patients

BACKGROUND

Imaging is a key diagnostic modality for suspected invasive pulmonary or sinus fungal disease and may help to direct testing and treatment. Fungal diagnostic guidelines have been developed and emphasize the role of imaging in this setting. We review and summarize evidence regarding imaging for fungal pulmonary and sinus disease (in particular invasive aspergillosis, mucormycosis and pneumocystosis) in immunocompromised patients.

OBJECTIVES

We reviewed data on imaging modalities and findings used for diagnosis of invasive fungal pulmonary and sinus disease.

SOURCES

References for this review were identified by searches of PubMed, Google Scholar, Embase and Web of Science through 1 April 1 2023.

CONTENT

Computed tomography imaging is the method of choice for the evaluation of suspected lung or sinus fungal disease. Although no computed tomography radiologic pattern is pathognomonic of pulmonary invasive fungal disease (IFD) the halo sign firstly suggests an angio-invasive pulmonary aspergillosis while the Reversed Halo Sign is more suggestive of pulmonary mucormycosis in an appropriate clinical setting. The air crescent sign is uncommon, occurring in the later stages of invasive aspergillosis in neutropenic patients. In contrast, new cavitary lesions should suggest IFD in moderately immunocompromised patients. Regarding sinus site, bony erosion, peri-antral fat or septal ulceration are reasonably predictive of IFD.

IMPLICATIONS

Imaging assessment of the lung and sinuses is an important component of the diagnostic work-up and management of IFD in immunocompromised patients. However, radiological features signs have sensitivity and specificity that often vary according to underlying disease states. Periodic review of imaging studies and diagnostic guidelines characterizing imaging findings may help clinicians to consider fungal infections in clinical care thereby leading to an earlier confirmation and treatment of IFD.

Radiological Diagnosis of Pulmonary Aspergillosis

Imaging plays an important role in the various forms of Aspergillus-related pulmonary disease. Depending on the immune status of the patient, three forms are described with distinct imaging characteristics: invasive aspergillosis affecting severely immunocompromised patients, chronic pulmonary aspergillosis affecting less severely immunocompromised patients but suffering from a pre-existing structural lung disease, and allergic bronchopulmonary aspergillosis related to respiratory exposure to Aspergillus species in patients with asthma and cystic fibrosis. Computed tomography (CT) has been demonstrated more sensitive and specific than chest radiographs and its use has largely contributed to the diagnosis, follow-up, and evaluation of treatment in each condition. In the last few decades, CT has also been described in the specific context of cystic fibrosis. In this particular clinical setting, magnetic resonance imaging and the recent developments in artificial intelligence have shown promising results.

Atypical imaging patterns during lung invasive mould diseases: lessons for clinicians

Imaging of pulmonary invasive mould diseases (IMDs), which represents a cornerstone in their work-up, is mainly based on computed tomography (CT). The purpose of this review is to discuss their CT features, mainly those related to aspergillosis and mucormycosis. We will especially focus on atypical radiological presentations that are increasingly observed among non-neutropenic emerging populations of patients at risk, such as those receiving novel anticancer therapies or those in the intensive care unit. We will also discuss the interest of other available imaging techniques, mainly positron emission tomography/CT, that may play a role in the diagnosis as well as evaluation of disease extent and follow-up. We will show that any new airway-centred abnormality or caveated lesion should evoke IMDs in mildly immunocompromised hosts. Limitations in their recognition may be due to potential underlying abnormalities that increase the complexity of interpretation of lung imaging, as well as the non-specificity of imaging features. In this way, the differentials of all morphological/metabolic aspects must be kept in mind for the optimal management of patients, as well as the benefit of evaluation of the vascular status.

Diagnosis and Treatment of Invasive Aspergillosis Caused by Non-fumigatus Aspergillus spp

With increasing frequency, clinical and laboratory-based mycologists are consulted on invasive fungal diseases caused by rare fungal species. This review aims to give an overview of the management of invasive aspergillosis (IA) caused by non-fumigatus Aspergillus spp.-namely A. flavus, A. terreus, A. niger and A. nidulans-including diagnostic and therapeutic differences and similarities to A. fumigatus. A. flavus is the second most common Aspergillus spp. isolated in patients with IA and the predominant species in subtropical regions. Treatment is complicated by its intrinsic resistance against amphotericin B (AmB) and high minimum inhibitory concentrations (MIC) for voriconazole. A. nidulans has been frequently isolated in patients with long-term immunosuppression, mostly in patients with primary immunodeficiencies such as chronic granulomatous disease. It has been reported to disseminate more often than other Aspergillus spp. Innate resistance against AmB has been suggested but not yet proven, while MICs seem to be elevated. A. niger is more frequently reported in less severe infections such as otomycosis. Triazoles exhibit varying MICs and are therefore not strictly recommended as first-line treatment for IA caused by A. niger, while patient outcome seems to be more favorable when compared to IA due to other Aspergillus species. A. terreus-related infections have been reported increasingly as the cause of acute and chronic aspergillosis. A recent prospective international multicenter surveillance study showed Spain, Austria, and Israel to be the countries with the highest density of A. terreus species complex isolates collected. This species complex seems to cause dissemination more often and is intrinsically resistant to AmB. Non-fumigatus aspergillosis is difficult to manage due to complex patient histories, varying infection sites and potential intrinsic resistances to antifungals. Future investigational efforts should aim at amplifying the knowledge on specific diagnostic measures and their on-site availability, as well as defining optimal treatment strategies and outcomes of non-fumigatus aspergillosis.

Invasive Aspergillosis in the Intensive Care Unit

Invasive pulmonary aspergillosis (IPA) is a serious condition resulting in significant mortality and morbidity among patients in intensive care units (ICUs). There is a growing number of at-risk patients for this condition with the increasing use of immunosuppressive therapies. The diagnosis of IPA can be difficult in ICUs, and relies on integration of clinical, radiological, and microbiological features. In this review, we discuss patient populations at risk for IPA, as well as the diagnostic criteria employed. We review the fungal biomarkers used, as well as the challenges in distinguishing colonization with Aspergillus from invasive disease. We also address the growing concern of multidrug-resistant Aspergillosis and review the new and novel therapeutics which are in development to combat this.

Association between early diagnosis of and inpatient mortality from invasive pulmonary aspergillosis among patients without immunocompromised host factors: a nationwide observational study

OBJECTIVES

The incidence of invasive pulmonary aspergillosis (IPA) among patients without immunocompromised host factors (ICHF) has been described extensively. However, its diagnosis remains challenging. To date, no study has statistically confirmed the efficacy of early IPA diagnosis in patients without ICHF.

METHODS

We conducted a cross-sectional study on mortality from IPA among patients without ICHF, using the Japanese Diagnosis Procedure Combination National Inpatient Database (April 2014-March 2018). The early diagnosis group was defined according to antifungal therapy initiation within 7 days of hospital admission. The delayed diagnosis group was defined according to antifungal therapy initiation between 8 and 28 days of the hospitalization. Associations were estimated using multivariate logistic regression.

RESULTS

A total of 423 patients were registered (early diagnosis group, n = 262, 62%). The early diagnosis group had a lower mortality rate (30%) than the delayed diagnosis group (42%). The early diagnosis group that was treated with voriconazole was associated with lower odds of mortality (odds ratio 0.55, 95% confidence interval 0.31-0.99, P = 0.047). An age of ≥65 years and mechanical ventilation were associated with a higher mortality rate.

CONCLUSION

Early diagnosis along with optimal antifungal treatment are crucial for achieving favorable outcomes among patients with IPA without ICHF.

Voriconazole Therapeutic Drug Monitoring Among Lung Transplant Recipients Receiving Targeted Therapy for Invasive Aspergillosis

BACKGROUND

Voriconazole is the first line treatment for invasive aspergillosis (IA) Current guidelines suggest performing regular voriconazole therapeutic drug monitoring (TDM) to optimize treatment efficacy. We aimed to determine if TDM was predictive of clinical outcome in LTRs.

METHODS

Retrospective chart review was performed for all LTRs with probable or proven IA, treated with voriconazole monotherapy and who underwent TDM during therapy. Clinical outcome and toxicity were measured at 12 weeks. Classification and regression tree (CART) analysis was used to determine the most predictive voriconazole level thresholds for successful outcome.

RESULTS

118 TDM samples from 30 LTRs with IA were analyzed. Three LTRs were excluded due to early treatment discontinuation. The median TDM level was 1.2 μg/mL (range 0.06-7.3). At 12 weeks, 62% (17/27) of patients had a successful outcome, while 37% (10/27) of patients failed therapy. CART analysis determined that the best predictor for successful outcome was a median TDM level > 0.72 μg/mL. Seventy percent (14/20) of patients with median TDM above 0.72 μg/mL had a successful outcome, compared to 42.9% (3/7) of patients with a median TDM below 0.72 μg/mL (OR 3.11; 95% CI: 0.53-20.4; P = 0.21). CART analysis determined that a TDM level greater than 2.13 μg/mL was predictive of hepatotoxicity.

CONCLUSIONS

Our data suggests that a voriconazole TDM range between 0.72 μg/mL and 2.13 μg/mL may be associated with improved outcomes. Our study is in line with current recommendations on the use of voriconazole TDM in improving outcome and minimizing toxicity in LTR with IA. This article is protected by copyright. All rights reserved.

Successful Management of Mixed Mycosis in HIV-Negative Patients With Different Immune Status: A Case Series Report

Objective

The limited information available on mixed mycosis involving the lungs makes the understanding of mixed fungal diseases insufficient and affects prognosis. Our study aims to improve understanding by exploring experience in the successful management of mixed fungal infections.

Methods

Patients who had two types of mycosis involving the lung at the same disease course were retrospectively enrolled.

Results

Between September 2011 and December 2019, 17 patients with proven mixed mycosis were enrolled. Four patients were immunocompromised, with one case each of lung transplantation, corticosteroid treatment, STAT3 hyper-IgE syndrome, and anti-IFN-γ autoantibody-associated immunodeficiency syndrome. Among 13 patients who were not immunocompromised, 9 had type 2 diabetes mellitus. Eight cases were coinfection with Mucor and Aspergillus, 4 cases were Cryptococcus and Aspergillus, 2 cases were Talaromyces marneffei and Cryptococcus, 2 cases were Talaromyces marneffei and Aspergillus, and 1 case was Candida and Aspergillus. Seven patients were diagnosed with mixed pulmonary mycosis at almost the same time. Among the remaining 10 patients, the initial treatment was ineffective in four cases, and six patients showed a partial response to the initial antifungal treatment, but the original fungal lesions became re-enlarged. Three patients were admitted to the intensive care unit during hospitalization, and one patient died. Another Mucor coinfection patient died due to treatment refusal.

Conclusion

Mixed mycosis involving the lungs is not uncommon in patients without apparent immune deficiency diseases. During the management of mycosis, we recommend keeping mixed mycosis in mind for patients with a poor response to initial antifungal treatment, even in immunocompetent populations, and identifying the cause of illness through a rigorous procedure.

Invasive pulmonary aspergillosis in solid-organ transplant patients in the intensive care unit

INTRODUCTION

Solid-organ transplantation (SOT) is a well-known risk factor for invasive pulmonary aspergillosis (IPA). We report on the epidemiology and outcome of SOT patients with IPA in an intensive care unit (ICU) setting.

METHODS

This is a secondary study based on a subset of SOT patients from a prospective observational multicenter cohort (the AspICU project) including ICU patients with at least one Aspergillus spp. positive culture. Cases were classified as proven, probable, or putative IPA, or as Aspergillus-colonized. Mortality was reported at 12 weeks.

RESULTS

The study included 52 SOT patients (of which 18 lung, 17 liver, 12 kidney, and five heart transplants). Sixteen patients had proven IPA, 28 were categorized as putative IPA (of which only five reached a probable IPA diagnosis according to the European Organization for Research and Treatment of Cancer/Mycosis Study Group and Research Consortium criteria), and eight as Aspergillus-colonization. Among patients with IPA, 20 (45.5%) developed IPA during their ICU stay following transplantation whereas 24 patients (54.5%) had a medical ICU admission. Regarding medical imaging, nearly all IPA cases presented with non-specific findings as only nine demonstrated robust findings suggestive for invasive fungal disease. Overall, severity of the disease was reflected by a high prevalence of underlying conditions and acute organ derangements. Mortality among patients with IPA was 68%. Lung transplantation was associated with better survival (50%).

CONCLUSION

IPA in SOT patients in the ICU develops in the presence of overall high severity of the disease. It rarely presents with suggestive medical imaging thereby hampering diagnosis. IPA in ICU patients with SOT carries a grim prognosis.

Radionuclide Imaging of Invasive Fungal Disease in Immunocompromised Hosts

Invasive fungal disease (IFD) leads to increased mortality, morbidity, and costs of treatment in patients with immunosuppressive conditions. The definitive diagnosis of IFD relies on the isolation of the causative fungal agents through microscopy, culture, or nucleic acid testing in tissue samples obtained from the sites of the disease. Biopsy is not always feasible or safe to be undertaken in immunocompromised hosts at risk of IFD. Noninvasive diagnostic techniques are, therefore, needed for the diagnosis and treatment response assessment of IFD. The available techniques that identify fungal-specific antigens in biological samples for diagnosing IFD have variable sensitivity and specificity. They also have limited utility in response assessment. Imaging has, therefore, been applied for the noninvasive detection of IFD. Morphologic imaging with computed tomography (CT) and magnetic resonance imaging (MRI) is the most applied technique. These techniques are neither sufficiently sensitive nor specific for the early diagnosis of IFD. Morphologic changes evaluated by CT and MRI occur later in the disease course and during recovery after successful treatment. These modalities may, therefore, not be ideal for early diagnosis and early response to therapy determination. Radionuclide imaging allows for targeting the host response to pathogenic fungi or specific structures of the pathogen itself. This makes radionuclide imaging techniques suitable for the early diagnosis and treatment response assessment of IFD. In this review, we aimed to discuss the interplay of host immunity, immunosuppression, and the occurrence of IFD. We also discuss the currently available radionuclide probes that have been evaluated in preclinical and clinical studies for their ability to detect IFD.

Fungal pneumonia in kidney transplant recipients

Fungal pneumonia is a dreaded complication encountered after kidney transplantation, complicated by increased mortality and often associated with graft failure. Diagnosis can be challenging because the clinical presentation is non-specific and diagnostic tools have limited sensitivity and specificity in kidney transplant recipients and must be interpreted in the context of the clinical setting. Management is difficult due to the increased risk of dissemination and severity, multiple comorbidities, drug interactions and reduced immunosuppression which should be applied as an important adjunct to therapy. This review will focus on the main causes of fungal pneumonia in kidney transplant recipients including Pneumocystis, Aspergillus, Cryptococcus, mucormycetes and Histoplasma. Epidemiology, clinical presentation, laboratory and radiographic features, specific characteristics will be discussed with an update on diagnostic procedures and treatment.

Guidance on Imaging for Invasive Pulmonary Aspergillosis and Mucormycosis: From the Imaging Working Group for the Revision and Update of the Consensus Definitions of Fungal Disease from the EORTC/MSGERC

BACKGROUND

Clinical imaging in suspected invasive fungal disease (IFD) has a significant role in early detection of disease and helps direct further testing and treatment. Revised definitions of IFD from the EORTC/MSGERC were recently published and provide clarity on the role of imaging for the definition of IFD. Here, we provide evidence to support these revised diagnostic guidelines.

METHODS

We reviewed data on imaging modalities and techniques used to characterize IFDs.

RESULTS

Volumetric high-resolution computed tomography (CT) is the method of choice for lung imaging. Although no CT radiologic pattern is pathognomonic of IFD, the halo sign, in the appropriate clinical setting, is highly suggestive of invasive pulmonary aspergillosis (IPA) and associated with specific stages of the disease. The ACS is not specific for IFD and occurs in the later stages of infection. By contrast, the reversed halo sign and the hypodense sign are typical of pulmonary mucormycosis but occur less frequently. In noncancer populations, both invasive pulmonary aspergillosis and mucormycosis are associated with "atypical" nonnodular presentations, including consolidation and ground-glass opacities.

CONCLUSIONS

A uniform definition of IFD could improve the quality of clinical studies and aid in differentiating IFD from other pathology in clinical practice. Radiologic assessment of the lung is an important component of the diagnostic work-up and management of IFD. Periodic review of imaging studies that characterize findings in patients with IFD will inform future diagnostic guidelines.

Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium

BACKGROUND

Invasive fungal diseases (IFDs) remain important causes of morbidity and mortality. The consensus definitions of the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group have been of immense value to researchers who conduct clinical trials of antifungals, assess diagnostic tests, and undertake epidemiologic studies. However, their utility has not extended beyond patients with cancer or recipients of stem cell or solid organ transplants. With newer diagnostic techniques available, it was clear that an update of these definitions was essential.

METHODS

To achieve this, 10 working groups looked closely at imaging, laboratory diagnosis, and special populations at risk of IFD. A final version of the manuscript was agreed upon after the groups' findings were presented at a scientific symposium and after a 3-month period for public comment. There were several rounds of discussion before a final version of the manuscript was approved.

RESULTS

There is no change in the classifications of "proven," "probable," and "possible" IFD, although the definition of "probable" has been expanded and the scope of the category "possible" has been diminished. The category of proven IFD can apply to any patient, regardless of whether the patient is immunocompromised. The probable and possible categories are proposed for immunocompromised patients only, except for endemic mycoses.

CONCLUSIONS

These updated definitions of IFDs should prove applicable in clinical, diagnostic, and epidemiologic research of a broader range of patients at high-risk.

Digestive enzymes of fungal origin as a relevant cause of false positive Aspergillus antigen testing in intensive care unit patients

Background

Galactomannan antigen (GM) testing is widely used in the diagnosis of invasive aspergillosis (IA). Digestive enzymes play an important role in enzyme substitution therapy in exocrine pancreatic insufficiency. As digestive enzymes of fungal origin like Nortase contain enzymes from Aspergillus, a false-positive result of the test might be possible because of cross-reacting antigens of the cell wall of the producing fungi. We, therefore, asked whether the administration of fungal enzymes is a relevant cause of false-positive GM antigen test results.

Methods

Patients with a positive GM antigen test between January 2016 and April 2020 were included in the evaluation and divided into two groups: group 1—Nortase-therapy, group 2—no Nortase-therapy. In addition, dissolved Nortase samples were analyzed in vitro for GM and β-1,3-D-glucan. For statistical analysis, the chi-squared and Mann‒Whitney U tests were used.

Results

Sixty-five patients were included in this evaluation (30 patients receiving Nortase and 35 patients not receiving Nortase). The overall false positivity rate of GM testing was 43.1%. Notably, false-positive results were detected significantly more often in the Nortase group (73.3%) than in the control group (17.1%, p < 0.001). While the positive predictive value of GM testing was 0.83 in the control group, there was a dramatic decline to 0.27 in the Nortase group. In vitro analysis proved that the Nortase enzyme preparation was highly positive for the fungal antigens GM and β-1,3-D-glucan.

Conclusions

Our data demonstrate that the administration of digestive enzymes of fungal origin like Nortase leads to a significantly higher rate of false-positive GM test results compared to that in patients without digestive enzyme treatment.

Diagnosis and treatment of invasive fungal infections: looking ahead

Improved standards of care depend on the development of new laboratory diagnostic and imaging procedures and the development of new antifungal compounds. Immunochromatography technologies have led to the development of lateral flow devices for the diagnosis of cryptococcal meningitis and invasive aspergillosis (IA). Similar devices are being developed for the detection of histoplasmosis that meet the requirements for speed (∼15 min assay time) and ease of use for point-of-care diagnostics. The evolution of molecular tools for the detection of fungal pathogens has been slow but the introduction of new nucleic acid amplification techniques appears to be helpful, for example T2Candida. An Aspergillus proximity ligation assay has been developed for a rapid near-patient bedside diagnosis of IA. CT remains the cornerstone for radiological diagnosis of invasive pulmonary fungal infections. MRI of the lungs may be performed to avoid radiation exposure. MRI with T2-weighted turbo-spin-echo sequences exhibits sensitivity and specificity approaching that of CT for the diagnosis of invasive pulmonary aspergillosis. The final part of this review looks at new approaches to drug discovery that have yielded new classes with novel mechanisms of action. There are currently two new classes of antifungal drugs in Phase 2 study for systemic invasive fungal disease and one in Phase 1. These new antifungal drugs show promise in meeting unmet needs with oral and intravenous formulations available and some with decreased potential for drug-drug interactions. Novel mechanisms of action mean these agents are not susceptible to the common resistance mechanisms seen in Candida or Aspergillus. Modification of existing antifungal susceptibility testing techniques may be required to incorporate these new compounds.

CT Halo sign: A systematic review. Eur J Radiol. 2020;124:108843. [PMID: 32007819 DOI: 10.1016/j.ejrad.2020.108843]

PURPOSE

The CT Halo sign or Halo sign (HS) refers to ground-glass opacity surrounding a nodule or mass in the lung parenchyma. We conducted a systematic review to find the etiological associations of HS. We also evaluated the diagnostic performances of HS for invasive fungal infections (IFI) in immunosuppressed patients.

METHOD

The systematic review was conducted as per PRISMA guidelines. We searched the PubMed and EMBASE database till June 2018 without any restrictions. Only case reports, case series and original articles published in English language were included. A database created from the electronic searches was compiled and subsequent analysis was done. [PROSPERO registration: CRD42018094739] RESULTS: 168 studies were eligible, which included 51 case reports, 15 prospective studies, 102 retrospective studies. A total of 1977 patients (out of 6371) with HS were identified with age range between <1year-94years. The most common diagnosis in the immunosuppressed, mixed, immunocompetent and not specified groups were IFI (86.9 %, n = 1194), Cryptococcosis (51.6 %, n = 124), Cryptococcosis (40 %, n = 20) and lung neoplasms (81.8 %, n = 36) respectively. 14 studies (11 retrospective, 3 prospective) were included in quantitative analysis. The pooled sensitivity(sn), specificity(sp) and odd's ratio (OR) of HS for diagnosing IFI were 50.4 %, 91 % and 6.61 respectively. Also, HS could not reliably differentiate IPA from mucormycosis in the pooled analysis.

CONCLUSIONS

HS can be seen in a large number of diverse conditions both in immunosuppressed and immunocompetent population. In immunosuppressed patients HS is specific for IFI but cannot rule it out. Additionally, it cannot reliably distinguish between IPA and mucormycosis.

Baseline predictors influencing the prognosis of invasive aspergillosis in adults

Invasive aspergillosis (IA) is a serious hazard to haematological and critical care patients. Impactful risk factors for developing IA have been characterised; however, systematic analysis of baseline prognostic factors for treatment course of IA is missing. To understand prognostic variables, we analysed original articles identifying baseline factors that predict treatment outcome in patients with IA. PubMed database was searched for publications since database inception until May 2018. Inclusion criteria were published baseline prognostic factors present at the diagnosis of IA. In total, 58 studies from 267 centres reported 7320 patients with IA and 40 different predictors. Unfavourable predictors in medical history were kidney (7.4%, 10/136) and liver failure (3.7%, 5/136), ICU admission (3.7%, 5/136) and uncontrolled underlying disease (3.7%, 5/136). Regarding state of immunosuppression, negative outcome predictors were prolonged neutropenia (12.5%, 17/136), corticosteroid treatment (8.1%, 11/136) and graft-vs-host disease (3.7%, 5/136). On the pathogen side, relevant predictors were galactomannan positivity (8.1%, 11/136), Aspergillus terreus infection (2.2%, 3/136) and lack of amphotericin B susceptibility (1.5%, 2/136). IA-specific predictors were disseminated disease (5.1%, 7/136) and CNS involvement (2.9%, 4/136). Imaging results associated with negative outcome were multiple consolidations (2.9%, 4/136), bipulmonary lesions (2.2%, 3/136) and pleural effusion (2.2%, 3/136). At diagnosis of IA, most frequently identified predictors of outcome were neutropenia, corticosteroid use, elevated galactomannan, renal failure and disseminated disease. The predictors may be used to identify patients at high risk for treatment failure and to stratify neglected patient groups for clinical trials.

Invasive Aspergillosis in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines provide information on epidemiology, diagnosis, and management of Aspergillus after organ transplantation. Aspergillus is the most common invasive mold infection in solid-organ transplant (SOT) recipients, and it is the most common invasive fungal infection among lung transplant recipients. Time from transplant to diagnosis of invasive aspergillosis (IA) is variable, but most cases present within the first year post-transplant, with shortest time to onset among liver and heart transplant recipients. The overall 12-week mortality of IA in SOT exceeds 20%; prognosis is worse among those with central nervous system involvement or disseminated disease. Bronchoalveolar lavage galactomannan is preferred for the diagnosis of IA in lung and non-lung transplant recipients, in combination with other diagnostic modalities (eg, chest CT scan, culture). Voriconazole remains the drug of choice to treat IA, with isavuconazole and lipid formulations of amphotericin B regarded as alternative agents. The role of combination antifungals for primary therapy of IA remains controversial. Either universal prophylaxis or preemptive therapy is recommended in lung transplant recipients, whereas targeted prophylaxis is favored in liver and heart transplant recipients. In these guidelines, we also discuss newer antifungals and diagnostic tests, antifungal susceptibility testing, and special patient populations.

Clinical diagnostic value of spiral CT in invasive pulmonary fungal infection

This study explored the diagnostic value of computed tomography (CT) in pulmonary fungal infection to provide a theoretical basis for the clinical diagnosis of pulmonary fungal infections. The clinical data of 82 suspected invasive fungal infection (IFI) patients admitted to the Department of Critical Care Medicine of The Affiliated Hospital of Qingdao University from January 2016 to May 2018 were retrospectively analyzed, and 64 of them were diagnosed with IFI by pathology and sputum culture. The CT results of the 82 patients were compared with the X-ray results in order to analyze the diagnostic value of CT imaging. Taking pathological diagnosis as the gold standard, the number of true-negative, true-positive, false-negative and false-positive results in X-ray diagnosis were 13, 43, 21 and 5, respectively, while those in CT diagnosis were 11, 59, 5 and 7, respectively. The sensitivity, specificity, accuracy, positive coincidence rate, negative coincidence rate, misdiagnosis rate and missed diagnosis rate of CT in IFI were 92.18, 61.11, 85.37, 89.39, 68.75, 38.89 and 7.81%, respectively, while those of X-ray in IFI were 67.19, 72.22, 68.29, 89.58, 38.24, 27.78 and 32.81%, respectively. The sensitivity, accuracy and negative coincidence rate of CT in the diagnosis of IFI were significantly higher than those of X-ray (P<0.05), with a sensitivity of 92.18%, which indicates that CT has a higher diagnostic value in IFI. The results of CT combined with the basic condition of the patients can be used to initially diagnose pulmonary fungal infections, which is of high diagnostic value and can improve clinical treatment.

Use of echinocandin prophylaxis in solid organ transplantation

Invasive fungal infections (IFIs) are a major threat to patients undergoing solid organ transplantation (SOT). Owing to improvements in surgical techniques, immunosuppression therapy and antifungal prophylaxis, the incidence of IFIs has been decreasing in recent years. However, IFI-associated morbidity and mortality remain significant. Invasive candidiasis (IC) and aspergillosis (IA) are the main IFIs after SOT. Risk factors for IC and IA continue to evolve, and thus strategies for their prevention should be constantly updated and targeted to both individual patient risk factors and local epidemiology. In this review, we discuss the current epidemiology and risk factors for IFIs in SOT recipients in the context of actual approaches to antifungal prophylaxis, including experience with the use of echinocandins, after SOT.

Current State of the Diagnosis of Invasive Pulmonary Aspergillosis in Lung Transplantation

As the number of lung transplants performed worldwide each year continues to grow, the success of this procedure is threatened by the incidence of non-CMV infections such as invasive aspergillosis. Despite tremendous efforts and the availability of numerous diagnostic tests (especially in hematological malignancies) the diagnosis of invasive aspergillosis continues to be a challenge. Lung transplantation remains a unique clinical scenario, where additional host defenses are immunocompromized, making many of the available tests unsuitable. In this review we will navigate through the myriad of diagnostic tests currently available and how they apply to this unique patient population, as well as have a look into what the future holds.

Epidemiology and clinical characteristics of invasive mould infections: A multicenter, retrospective analysis in five Asian countries

Formal, large-scale, multicenter studies of invasive mould infection (IMI) in Asia are rare. This 1-year, retrospective study was designed to assess the incidence and clinical determinants of IMI in centers in five countries (Thailand, Taiwan, Singapore, China, India). Patients treated in a single year (2012) were identified through discharge diagnoses, microbiology, and histopathology logs, and entered based on published definitions of IMI. A total of 155 cases were included (median age 54 years; 47.7% male). Of these, 47.7% had proven disease; the remainder had probable IMI. The most frequent host factors were prolonged steroid use (39.4%) and recent neutropenia (38.7%). Common underlying conditions included diabetes mellitus (DM; 30.9%), acute myeloid leukemia (19.4%), and rheumatologic conditions (11.6%). DM was more common in patients with no recent history of neutropenia or prolonged steroid use (P = .006). The lung was the most frequently involved site (78.7%), demonstrating a range of features on computed tomography (CT). Aspergillus was the most common mould cultured (71.6%), primarily A. fumigatus and A. flavus, although proportions varied in different centers. The most often used antifungal for empiric therapy was conventional amphotericin. Ninety-day mortality was 32.9%. This is the first multicenter Asian study of IMI not limited to specific patient groups or diagnostic methods. It suggests that DM and rheumatologic conditions be considered as risk factors for IMI and demonstrates that IMI should not be ruled out in patients whose chest features on CT do not fit the conventional criteria.

Epidemiology, risk factors and outcomes of invasive aspergillosis in solid organ transplant recipients in the Swiss Transplant Cohort Study

BACKGROUND

There is lack of recent multicenter epidemiological data on invasive aspergillosis (IA) among solid organ transplant recipient (SOTr) in the mold-acting antifungal era. We describe the epidemiology and outcomes of IA in a contemporary cohort of SOTr using the Swiss Transplant Cohort Study.

METHODS

All consecutive SOTr with proven or probable IA between 01.05.2008 and 31.12.2014 were included. A case-control study to identify IA predictors was performed: 1-case was matched with 3-controls based on SOT type, transplant center, and time post-SOT.

RESULTS

Among 2868 SOTr, 70 (2.4%) patients were diagnosed with proven (N: 30/70, 42.9%) or probable (N: 40/70, 57.1%) IA. The incidence of IA was 8.3%, 7.1%, 2.6%, 1.3%, and 1.2% in lung, heart, combined, kidney, and liver transplant recipients, respectively, Galactomannan immunoassay was positive in 1/3 of patients tested. Only 33/63 (52.4%) of patients presented with typical pulmonary radiographic findings. Predictors of IA included: renal insufficiency, re-operation, and bacterial and viral infections. 12-week mortality was higher in liver (85.7%, 6/7) compared to other (15.9%, 10/63; P < .001) SOTr.

CONCLUSIONS

Invasive aspergillosis remains a rare complication post-SOT, with atypical radiographic presentations and low positivity rates of biomarkers posing significant diagnostic challenges. Although overall mortality has decreased in SOTr, it remains high in liver SOTr.

[Invasive pulmonary aspergillosis]

INTRODUCTION

Invasive pulmonary aspergillosis (IPA) is an important cause of morbidity and mortality in a wide range of patients. Early recognition and diagnosis have become a major focus in improving the management and outcomes of this life-threatening disease.

BACKGROUND

IPA typically occurs during a period of severe and prolonged neutropenia. However, solid organ transplant recipients, patients under immunosuppressive therapy or hospitalized in intensive care units are also at risk. The diagnosis is suspected in the presence of a combination of clinical, biological and CT scan evidence. The microbiological diagnostic strategy should be adapted to the patient's profile. Conventional methods with culture and species identification remain the standard but early diagnosis has been improved by the use of biomarkers such as galactomannan antigen in serum or in bronchoalveolar lavage.

OUTLOOK

The epidemiology of IPA should change with the increased use of antifungal prophylactic regimens and the arrival of targeted therapies. Other microbiological tools, such as PCR and other biomarkers, are currently being assessed.

CONCLUSIONS

IPA must be considered in a wide range of patients. Its prognosis remains poor despite progress in the microbiological diagnosis and therapeutic management.

Respiratory Fungal Infections in Solid Organ and Hematopoietic Stem Cell Transplantation

Respiratory fungal infections are associated with high morbidity and mortality in hematopoietic stem cell (HSCT) and solid organ (SOT) transplant recipients, and are caused primarily by molds. Aspergillus is the most common pathogen. The net state of immunosuppression plays a major role in the risk of respiratory fungal infections after transplantation. Clinical presentation can be atypical and diagnosis can be delayed due to low sensitivity of diagnostic methods or inability to obtain adequate specimens. Fungal infections in HSCT and SOT carry a higher risk of dissemination. New prophylaxis strategies have changed the epidemiology of fungal infections in this patient population.

Early diagnosis of invasive mould infections and disease

Invasive mould infections (IMIs), such as invasive aspergillosis or mucormycosis, are a major cause of death in patients with haematological cancer and in patients receiving long-term immunosuppressive therapy. Early diagnosis and prompt initiation of antifungal therapy are crucial steps in the management of patients with IMI. The diagnosis of IMI remains a major challenge, with an increased spectrum of fungal pathogens and a diversity of clinical and radiological presentations within the expanding spectrum of immunocompromised hosts. Diagnosis is difficult to establish and is expressed on a scale of probability (proven, probable and possible). Imaging (CT scan), microbiological tools (direct examination, culture, PCR, fungal biomarkers) and histopathology are the pillars of the diagnostic work-up of IMI. None of the currently available diagnostic tests provides sufficient sensitivity and specificity alone, so the optimal approach relies on a combination of multiple diagnostic strategies, including imaging, fungal biomarkers (galactomannan and 1,3-β-d-glucan) and molecular tools. In recent years, the development of PCR for filamentous fungi (primarily Aspergillus or Mucorales) and the progress made in the standardization of fungal PCR technology, may lead to future advances in the field. The appropriate diagnostic approach for IMI should be individualized to each centre, taking into account the local epidemiology of IMI and the availability of diagnostic tests.

Clinical characteristics, radiologic findings, risk factors and outcomes of serum galactomannan-negative invasive pulmonary aspergillosis

BACKGROUND

The sensitivity of galactomannan (GM) assay is suboptimal for detecting invasive pulmonary aspergillosis (IPA) in serum samples. However, the clinical characteristics, radiologic findings, and outcomes in patients with GM-negative IPA have not been fully elucidated.

METHODS

Over a 7-year period, adult patients with proven or probable IPA by the EORTC/MSG definition were retrospectively enrolled. Patients with negative GM results and positive Aspergillus spp. cultures from sputum or bronchoalveolar lavage were classified into GM-negative IPA group. GM-positive and culture-negative IPA cases were selected at a 1:2 ratio.

RESULTS

Thirty-four patients with GM-negative IPA were compared to 68 randomly selected patients from 158 patients with GM-positive and culture-negative IPA. Patients with diabetes mellitus, chronic kidney disease, and steroid use were more common but those with hematologic malignancy, prior receipt of mold-active antifungal drugs, and neutropenia were less common in GM-negative IPA than in GM-positive IPA. Regarding radiologic findings, angioinvasive aspergillosis was less common in GM-negative IPA than in GM-positive IPA. The median number of days from diagnosis to appropriate antifungal therapy was higher in GM-negative IPA than in GM-positive IPA. Multivariate analysis indicated that neutropenia (adjusted odds ratio [aOR], 0.10) and prior receipt of mold-active antifungal drugs (aOR, 0.12) were inversely associated with GM-negative IPA. The 30-day and 90-day mortality were similar between the two groups.

CONCLUSION

Neutropenia and prior receipt of mold-active antifungal drugs before GM assay were independently associated with GM positivity among patients with proven/probable IPA. Angioinvasive aspergillosis was less common in GM-negative IPA than in GM-positive IPA.

Approach to the Solid Organ Transplant Patient with Suspected Fungal Infection

In solid organ transplant (SOT) recipients, invasive fungal infections (IFIs) are associated with significant morbidity and mortality. Detection of IFIs can be difficult because the signs and symptoms are similar to those of viral or bacterial infections, and diagnostic techniques have limited sensitivity and specificity. Clinicians must rely on knowledge of the patient's risk factors for fungal infection to make a diagnosis. The authors describe their approach to the SOT recipient with suspected fungal infection. The epidemiology of IFIs in the SOT population is reviewed, and a syndromic approach to suspected IFI in SOT recipients is described.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

Immune reconstitution inflammatory syndrome in neutropenic patients with invasive pulmonary aspergillosis

OBJECTIVES

Clinical and radiologic deterioration is sometimes observed during neutrophil recovery in patients with invasive pulmonary aspergillosis (IPA). This deterioration can be caused by immune reconstitution inflammatory syndrome (IRIS) as well as by progression of the IPA. However, there is limited data on IRIS in neutropenic patients.

METHODS

Over a 6-year period, adult patients with neutropenia who met the criteria for probable or proven IPA by the revised EORTC/MSG definition were retrospectively enrolled. IRIS was defined as de novo appearance or worsening of radiologic pulmonary findings temporally related to neutrophil recovery, with evidence of a decrease of 50% in serum galactomannan level.

RESULTS

Of 153 patients, 36 (24%, 95% CI 18%-31%) developed IRIS during neutrophil recovery. More of these patients received voriconazole than did those with non-IRIS (42% vs. 25%, P = 0.05). Thirty- and ninety-day mortalities were lower in the patients with IRIS than in those with non-IRIS (11% vs. 33%, P = 0.01, and 33% vs. 58%, P = 0.01, respectively).

CONCLUSION

IRIS is relatively common among neutropenic patients with IPA, occurring in about one quarter of such patients. It is associated with voriconazole use and has a good prognosis.

[Mold infections in lung transplants]

Invasive infections by molds, mainly Aspergillus infections, account for more than 10% of infectious complications in lung transplant recipients. These infections have a bimodal presentation: an early one, mainly invading bronchial airways, and a late one, mostly focused on lung or disseminated. The Aspergillus colonization at any time in the post-transplant period is one of the major risk factors. Late colonization, together with chronic rejection, is one of the main causes of late invasive forms. A galactomannan value of 0.5 in bronchoalveolar lavage is currently considered a predictive factor of pulmonary invasive infection. There is no universal strategy in terms of prophylaxis. Targeted prophylaxis and preemptive treatment instead of universal prophylaxis, are gaining more followers. The therapeutic drug monitoring level of azoles is highly recommended in the treatment. Monotherapy with voriconazole is the treatment of choice in invasive aspergillosis; combined antifungal therapies are only recommended in severe, disseminated, and other infections due to non-Aspergillus molds.

Fungal infections in cancer patients

Invasive fungal infections (IFI) have become a leading cause of morbidity and mortality in cancer patients. Infections with these organisms are often difficult to diagnose and treat. Appropriate and timely diagnosis requires a high index of suspicion and invasive procedures, including biopsy, to confirm the diagnosis. Treatment may be difficult, secondary to variable susceptibility and difficulty with exact and specific characterization of the fungal pathogen. The pathogens that are seen range from yeasts to invasive molds. Fortunately newer, noninvasive diagnostic techniques are available to aid in the diagnosis and treatments have become better tolerated and more efficacious.

Invasive mold infections in solid organ transplant recipients

Invasive mold infections represent an increasing source of morbidity and mortality in solid organ transplant recipients. Whereas there is a large literature regarding invasive molds infections in hematopoietic stem cell transplants, data in solid organ transplants are scarcer. In this comprehensive review, we focused on invasive mold infection in the specific population of solid organ transplant. We highlighted epidemiology and specific risk factors for these infections and we assessed the main clinical and imaging findings by fungi and by type of solid organ transplant. Finally, we attempted to summarize the diagnostic strategy for detection of these fungi and tried to give an overview of the current prophylaxis treatments and outcomes of these infections in solid organ transplant recipients.

Histopathological implications of Aspergillus infection in lung

This paper opens with a discussion on the significance of invasive fungal infections in advanced contemporary medicine, with an emphasis on the intractability of disease management and the difficulties of diagnosis. This is followed by a discussion concerning classification, histopathological features, and pathophysiology. While it has been largely accepted that Aspergillus species is recognized by cellular receptors and attacked by neutrophils, the radiological and macroscopic findings linking infection with neutropenia remain unconfirmed. In an effort to gain a better understanding of the pathophysiology and pathogenesis of invasive aspergillosis, we wish to emphasize the utility of radiological and histopathological examinations since these can provide detailed information on the extremely complex interaction between the causative microbes and tissue responses. A review of noninvasive or semi-invasive aspergillosis is also provided, with particular emphasis on chronic necrotizing pulmonary aspergillosis, which is recognized as a transition form of simple pulmonary aspergilloma and invasive pulmonary aspergillosis, although few findings have been reported in this area.

CD8⁺ T-cell counts: an early predictor of risk and mortality in critically ill immunocompromised patients with invasive pulmonary aspergillosis

INTRODUCTION

Critically ill immunocompromised (CIIC) patients with pulmonary infection are a population at high risk for invasive pulmonary aspergillosis (IPA). The host defenses are important factors to consider in determining the risk and outcome of infection. Quantification of changes in the status of host immunity could be valuable for clinical diagnosis and outcome prediction.

METHODS

We evaluated the quantitative changes in key humoral and cellular parameters in CIIC patients with pulmonary infection and their potential influence on the risk and prognosis of IPA. We monitored the evolution of these parameters in 150 CIIC patients with pulmonary infection on days 1, 3 and 10 (D1, D3 and D10) following ICU admission. The primary outcome was 28-day mortality. Follow-up included 60- and 90-day mortality.

RESULTS

Among the 150 CIIC patients included in this study, 62 (41.3%) had microbiological evidence of IPA. Compared with patients without IPA, CD3⁺, CD8⁺, CD28⁺CD4⁺ and CD28⁺CD8⁺ CD28⁺CD8⁺ T-cell counts (D1, D3 and D10) and B-cell counts (D1 and D3) were significantly reduced in patients with IPA (P < 0.05). Multivariate regression analysis revealed that CD8⁺ (D3 and D10) (odds ratio (OR) 0.34, 95% confidence interval (CI) 0.23 to 0.46; OR 0.68, 95% CI 0.56 to 0.80), CD28⁺CD8⁺ (D3) (OR 0.73, 95% CI 0.61 to 0.86) and CD3⁺ (D10) (OR 0.81, 95% CI 0.63 to 0.98) T-cell counts were independent predictors of IPA in CIIC patients. Receiver operating characteristic analysis of immune parameters predicting 28-day mortality revealed area under the curve values of 0.82 (95% CI 0.71 to 0.92), 0.94 (95% CI 0.87 to 0.99), and 0.94 (95% CI 0.85 to 0.99) for CD8⁺ T-cell counts (D1, D3 and D10, respectively) and 0.84 (95% CI 0.75 to 0.94), 0.92 (95% CI 0.85 to 0.99) and 0.90 (95% CI 0.79 to 0.99) for CD28⁺CD8⁺ T-cell counts (D1, D3 and D10, respectively). Kaplan-Meier survival analysis provided evidence that CD8⁺ and CD28⁺CD8⁺ T-cell counts (<149.5 cells/mm³ and <75 cells/mm³, respectively) were associated with early mortality in CIIC patients with IPA (logrank test; P < 0.001).

CONCLUSIONS

CD8⁺ and CD28⁺CD8⁺ T-cell counts were significantly lower in CIIC patients with IPA than in non-IPA patients. Lower CD8⁺ and CD28⁺CD8⁺ T-cell counts in CIIC patients with pulmonary infection were associated with higher risk and early mortality in IPA and may be valuable for clinical diagnosis and outcome prediction.

Epidemiology, outcomes, and mortality predictors of invasive mold infections among transplant recipients: a 10-year, single-center experience

BACKGROUND

The epidemiology of invasive mold infections (IMI) in transplant recipients differs based on geography, hosts, preventative strategies, and methods of diagnosis.

METHODS

We conducted a retrospective observational study to evaluate the epidemiology of proven and probable IMI, using prior definitions, among all adult hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients in the era of "classic" culture-based diagnostics (2000-2009). Epidemiology was evaluated before and after an initiative was begun to increase bronchoscopy in HSCT recipients after 2005.

RESULTS

In total, 106 patients with one IMI were identified. Invasive aspergillosis (IA) was the most common IMI (69; 65.1%), followed by mucormycosis (9; 8.5%). The overall rate of IMI (and IA) was 3.5% (2.5%) in allogeneic HSCT recipients. The overall incidence for IMI among lung, kidney, liver, and heart transplant recipients was 49, 2, 11, and 10 per 1000 person-years, respectively. The observed rate of IMI among human leukocyte antigen-matched unrelated and haploidentical HSCT recipients increased from 0.6% annually to 3.0% after bronchoscopy initiation (P < 0.05). The 12-week mortality among allogeneic HSCT, liver, kidney, heart, and lung recipients with IMI was 52.4%, 47.1%, 27.8%, 16.7%, and 9.5%, respectively. Among allogeneic HSCT (odds ratio [OR]: 0.07, P = 0.007) and SOT (OR: 0.22, P = 0.05) recipients with IA, normal platelet count was associated with improved survival. Male gender (OR: 14.4, P = 0.007) and elevated bilirubin (OR: 5.7, P = 0.04) were significant predictors of mortality for allogeneic HSCT and SOT recipients with IA, respectively.

CONCLUSIONS

During the era of culture-based diagnostics, observed rates of IMI were low among all transplants except lung transplant recipients, with relatively higher mortality rates. Diagnostic aggressiveness and host variables impact the reported incidence and outcome of IMI and likely account for institutional variability in multicenter studies. Definitions to standardize diagnoses among SOT recipients are needed.