Challenges and Solution of Invasive Aspergillosis in Non-neutropenic Patients: A Review

An oxylipin signal confers protection against antifungal echinocandins in pathogenic aspergilli

Aspergillus fumigatus is the leading causative agent of life-threatening invasive aspergillosis in immunocompromised individuals. One antifungal class used to treat Aspergillus infections is the fungistatic echinocandins, semisynthetic drugs derived from naturally occurring fungal lipopeptides. By inhibiting beta-1,3-glucan synthesis, echinocandins cause both fungistatic stunting of hyphal growth and repeated fungicidal lysis of apical tip compartments. Here, we uncover an endogenous mechanism of echinocandin tolerance in A. fumigatus whereby the inducible oxylipin signal 5,8-diHODE confers protection against tip lysis via the transcription factor ZfpA. Treatment of A. fumigatus with echinocandins induces 5,8-diHODE synthesis by the fungal oxygenase PpoA in a ZfpA dependent manner resulting in a positive feedback loop. This protective 5,8-diHODE/ZfpA signaling relay is conserved among diverse isolates of A. fumigatus and in two other Aspergillus pathogens. Our findings reveal an oxylipin-directed growth program-possibly arisen through natural encounters with native echinocandin producing fungi-that enables echinocandin tolerance in pathogenic aspergilli.

Prognostic factors and outcomes of invasive pulmonary aspergillosis, a retrospective hospital-based study

Objective

Invasive pulmonary aspergillosis (IPA) affects immunocompromised hosts and is associated with higher risks of respiratory failure and mortality. However, the clinical outcomes of different IPA types have not been identified.

Methods

Between September 2002 and May 2021, we retrospectively enrolled patients with IPA in Taichung Veterans General Hospital, Taiwan. Cases were classified as possible IPA, probable IPA, proven IPA, and putative IPA according to EORTC/MSGERC criteria and the AspICU algorithm. Risk factors of respiratory failure, kidney failure, and mortality were analyzed by logistic regression. A total of 3-year survival was assessed by the Kaplan-Meier method with log-rank test for post-hoc comparisons.

Results

We included 125 IPA patients (50: possible IPA, 47: probable IPA, 11: proven IPA, and 17: putative IPA). Comorbidities of liver cirrhosis and solid organ malignancy were risk factors for respiratory failure; diabetes mellitus and post-liver or kidney transplantation were related to kidney failure. Higher galactomannan (GM) test optical density index (ODI) in either serum or bronchoalveolar lavage fluid was associated with dismal outcomes. Probable IPA and putative IPA had lower 3-year respiratory failure-free survival compared to possible IPA. Probable IPA and putative IPA exhibited lower 3-year renal failure-free survival in comparison to possible IPA and proven IPA. Putative IPA had the lowest 3-year overall survival rates among the four IPA groups.

Conclusion

Patients with putative IPA had higher mortality rates than the possible, probable, or proven IPA groups. Therefore, a prompt diagnosis and timely treatment are warranted for patients with putative IPA.

Circulatory Inflammatory Proteins as Early Diagnostic Biomarkers for Invasive Aspergillosis in Patients with Hematologic Malignancies-an Exploratory Study

OBJECTIVES

Invasive aspergillosis (IA) is a major cause of mortality in immunocompromised patients and it is difficult to diagnose because of the lack of reliable highly sensitive diagnostics. We aimed to identify circulating immunological markers that could be useful for an early diagnosis of IA.

METHODS

We collected longitudinally serum samples from 33 cases with probable/proven IA and two matched control cohorts without IA (one with microbiological and clinical evidence of bacterial or viral non-fungal pneumonia and one without evidence of infection, all matched for neutropenia, primary underlying disease, and receipt of corticosteroids/other immunosuppressants) at a tertiary university hospital. In addition, samples from an independent cohort (n = 20 cases of proven/probable IA and 20 matched controls without infection) were obtained. A panel of 92 circulating proteins involved in inflammation was measured by proximity extension assay. A random forest model was used to predict the development of IA using biomarkers measured before diagnosis.

RESULTS

While no significant differences were observed between IA cases and infected controls, concentrations of 30 inflammatory biomarkers were different between cases and non-infected controls, of which nine were independently replicated: PD-L1, MMP-10, Interleukin(IL)-10, IL-15RA, IL-18, IL-18R1, CDCP1, CCL19 and IL-17C. From the differential abundance analysis of serum samples collected more than 10 days before diagnosis and at diagnosis, increased IL-17C concentrations in IA patients were replicated in the independent cohort.

CONCLUSIONS

An increased circulating concentration of IL-17C was detected both in the discovery and independent cohort, both at the time of diagnosis and in samples 10 days before the diagnosis of IA, suggesting it should be evaluated further as potential (early) biomarker of infection.

Laboratory and clinical management capacity for invasive fungal infections: the Italian landscape

BACKGROUND

We assessed the laboratory diagnosis and treatment of invasive fungal disease (IFD) in Italy to detect limitations and potential for improvement.

METHODS

The survey was available online at www.clinicalsurveys.net/uc/IFI management capacity/, and collected variables such as (a) institution profile, (b) perceptions of IFD in the respective institution, (c) microscopy, (d) culture and fungal identification, (e) serology, (f) antigen detection, (g) molecular tests, (h) susceptibility testing and (i) therapeutic drug monitoring (TDM).

RESULTS

The laboratory capacity study received responses from 49 Italian centres, with an equitable geographical distribution of locations. The majority of respondents (n = 36, 73%) assessed the occurrence of IFD as moderate-high, with Aspergillus spp. being the pathogen of highest concern, followed by Candida spp. and Mucorales. Although 46 (94%) of the institutions had access to microscopy, less than half of them performed direct microscopy on clinical specimens always when IFD was suspected. Cultures were available in all assessed laboratories, while molecular testing and serology were available in 41 (83%), each. Antigen detection tests and antifungal drugs were also generally accessible (> 90%) among the participating institutions. Nevertheless, access to TDM was limited (n = 31, 63%), with a significant association established between therapeutic drug monitoring availability and higher gross domestic product per capita.

CONCLUSIONS

Apart from TDM, Italy is adequately prepared for the diagnosis and treatment of IFD, with no significant disparities depending on gross domestic product. Future efforts may need to focus on enhancing the availability and application of direct microscopic methods, as well as TDM, to promote optimal treatment and better patient outcomes.

The Novel Monoclonal IgG1-Antibody AB90-E8 as a Diagnostic Tool to Rapidly Distinguish Aspergillus fumigatus from Other Human Pathogenic Aspergillus Species

In most cases, invasive aspergillosis (IA) is caused by A. fumigatus, though infections with other Aspergillus spp. with lower susceptibilities to amphotericin B (AmB) gain ground. A. terreus, for instance, is the second leading cause of IA in humans and of serious concern because of its high propensity to disseminate and its in vitro and in vivo resistance to AmB. An early differentiation between A. fumigatus and non-A. fumigatus infections could swiftly recognize a potentially ineffective treatment with AmB and lead to the lifesaving change to a more appropriate drug regime in high-risk patients. In this study, we present the characteristics of the monoclonal IgG₁-antibody AB90-E8 that specifically recognizes a surface antigen of A. fumigatus and the closely related, but not human pathogenic A. fischeri. We show immunostainings on fresh frozen sections as well as on incipient mycelium picked from agar plates with tweezers or by using the expeditious tape mount technique. All three methods have a time advantage over the common procedures currently used in the routine diagnosis of IA and outline the potential of AB90-E8 as a rapid diagnostic tool.

Invasive Pulmonary Aspergillosis in Coronavirus Disease 2019 Patients Lights and Shadows in the Current Landscape

Invasive pulmonary aspergillosis (IPA) presents a known risk to critically ill patients with SARS-CoV-2; quantifying the global burden of IPA in SARS-CoV-2 is extremely challenging. The true incidence of COVID-19-associated pulmonary aspergillosis (CAPA) and the impact on mortality is difficult to define because of indiscriminate clinical signs, low culture sensitivity and specificity and variability in clinical practice between centers. While positive cultures of upper airway samples are considered indicative for the diagnosis of probable CAPA, conventional microscopic examination and qualitative culture of respiratory tract samples have quite low sensitivity and specificity. Thus, the diagnosis should be confirmed with serum and BAL GM test or positive BAL culture to mitigate the risk of overdiagnosis and over-treatment. Bronchoscopy has a limited role in these patients and should only be considered when diagnosis confirmation would significantly change clinical management. Varying diagnostic performance, availability, and time-to-results turnaround time are important limitations of currently approved biomarkers and molecular assays for the diagnosis of IA. The use of CT scans for diagnostic purposes is controversial due to practical concerns and the complex character of lesions presented in SARS-CoV-2 patients. The key objective of management is to improve survival by avoiding misdiagnosis and by initiating early, targeted antifungal treatment. The main factors that should be considered upon selection of treatment options include the severity of the infection, concomitant renal or hepatic injury, possible drug interactions, requirement for therapeutic drug monitoring, and cost of therapy. The optimal duration of antifungal therapy for CAPA is still under debate.

Exposure of Aspergillus fumigatus to Klebsiella pneumoniae Culture Filtrate Inhibits Growth and Stimulates Gliotoxin Production

Aspergillus fumigatus is an opportunistic fungal pathogen capable of inducing chronic and acute infection in susceptible patients. A. fumigatus interacts with numerous bacteria that compose the microbiota of the lung, including Pseudomonas aeruginosa and Klebsiella pneumoniae, both of which are common isolates from cystic fibrosis sputum. Exposure of A. fumigatus to K. pneumoniae culture filtrate reduced fungal growth and increased gliotoxin production. Qualitative proteomic analysis of the K. pneumoniae culture filtrate identified proteins associated with metal sequestering, enzymatic degradation and redox activity, which may impact fungal growth and development. Quantitative proteomic analysis of A. fumigatus following exposure to K. pneumoniae culture filtrate (25% v/v) for 24 h revealed a reduced abundance of 1,3-beta-glucanosyltransferase (-3.97 fold), methyl sterol monooxygenase erg25B (-2.9 fold) and calcium/calmodulin-dependent protein kinase (-4.2 fold) involved in fungal development, and increased abundance of glutathione S-transferase GliG (+6.17 fold), non-ribosomal peptide synthase GliP (+3.67 fold), O-methyltransferase GliM (+3.5 fold), gamma-glutamyl acyltransferase GliK (+2.89 fold) and thioredoxin reductase GliT (+2.33 fold) involved in gliotoxin production. These results reveal that exposure of A. fumigatus to K. pneumoniae in vivo could exacerbate infection and negatively impact patient prognosis.

Liposomal amphotericin B—the future

Advances in medicine have led to a growing number of people with compromised or suppressed immune systems who are susceptible to invasive fungal infections. In particular, severe fungal infections are becoming increasingly common in ICUs, affecting people within and outside of traditional risk groups alike. This is exemplified by the emergence of severe viral pneumonia as a significant risk factor for invasive pulmonary aspergillosis, and the recognition of influenza-associated pulmonary aspergillosis and, more recently, COVID-19-associated pulmonary aspergillosis.

The treatment landscape for haematological malignancies has changed considerably in recent years, and some recently introduced targeted agents, such as ibrutinib, are increasing the risk of invasive fungal infections. Consideration must also be given to the risk of drug–drug interactions between mould-active azoles and small-molecule kinase inhibitors.

At the same time, infections caused by rare moulds and yeasts are increasing, and diagnosis continues to be challenging. There is growing concern about azole resistance among both moulds and yeasts, mandating continuous surveillance and personalized treatment strategies.

It is anticipated that the epidemiology of fungal infections will continue to change and that new populations will be at risk. Early diagnosis and appropriate treatment remain the most important predictors of survival, and broad-spectrum antifungal agents will become increasingly important. Liposomal amphotericin B will remain an essential therapeutic agent in the armamentarium needed to manage future challenges, given its broad antifungal spectrum, low level of acquired resistance and limited potential for drug–drug interactions.

Comparative analysis of airway invasive aspergillosis and endobronchial spread of tuberculosis on high resolution computed tomography

The presence of tree-in-bud (T-I-B) pulmonary opacities on high resolution computed tomography (HRCT) in tuberculosis endemic areas is frequently regarded as a sine qua non for endobronchial tuberculosis (TB). That is not always the case, however. They can also be found in immunocompromised non-neutropenic patients with airway invasive aspergillosis (IA). Understanding the differences between the two conditions is thus critical for making an accurate diagnosis. This research aims to pinpoint those distinguishing characteristics. The study defines the distribution and morphology of T-I-B opacities and other ancillary pulmonary findings in the two conditions by performing a retrospective analysis of HRCT features in 53 immunocompromised patients with lower respiratory tract symptoms, 38 of whom were positive for TB on BAL fluid analysis and 15 confirmed IA by Galactomannan method. While the global distribution of T-I-B opacities affecting all lobes favoured TB (p=0.002), the basal distribution overwhelmingly favoured IA (p<0.0001). Morphologically, dense nodules with discrete margins were associated with TB, whereas nodules with ground-glass density and fuzzy margins were associated with IA. Clustering of nodules was observed in 18 TB patients (p=0.0008). Cavitation was found in 14 (36.84%) of TB patients but not in any of the IA patients. Peri-bronchial consolidation was found in seven (46.67%) of the IA cases and four (10.53%) of the TB cases (p=0.005, 0.007). The presence of ground-glass opacity and bronchiectasis did not differ significantly between the two groups. Not all T-I-B opacities on HRCT chest in immunocompromised patients in endemic TB areas should be reported as tubercular. Immunocompromised non-neutropenic patients with airway IA can be identified earlier with tree-in-bud opacities on HRCT chest, even in the absence of a nodule with halo, resulting in earlier and more effective management.

Diagnostic performance of mycological tests for invasive pulmonary aspergillosis in non-haematological patients: protocol for a systematic review and meta-analysis

INTRODUCTION

Increasing numbers of patients with non-haematological diseases are infected with invasive pulmonary aspergillosis (IPA), with a high mortality reported which is mainly due to delayed diagnosis. The diagnostic capability of mycological tests for IPA including galactomannan test, (1,3)-β-D-glucan test, lateral flow assay, lateral flow device and PCR for the non-haematological patients remains unknown. This protocol aims to conduct a systematic review and meta-analysis of the diagnostic performance of mycological tests to facilitate the early diagnosis and treatments of IPA in non-haematological diseases.

METHODS AND ANALYSIS

Database including PubMed, CENTRAL and EMBASE will be searched from 2002 until the publication of results. Cohort or cross-sectional studies that assessing the diagnostic capability of mycological tests for IPA in patients with non-haematological diseases will be included. The true-positive, false-positive, true-negative and false-negative of each test will be extracted and pooled in bivariate random-effects model, by which the sensitivity and specificity will be calculated with 95% CI. The second outcomes will include positive (negative) likelihood ratio, area under the receiver operating characteristic curve and diagnostic OR will also be computed in the bivariate model. When applicable, subgroup analysis will be performed with several prespecified covariates to explore potential sources of heterogeneity. Factors that may impact the diagnostic effects of mycological tests will be examined by sensitivity analysis. The risk of bias will be appraised by the Quality Assessment tool for Diagnostic Accuracy Studies (QUADAS-2).

ETHICS AND DISSEMINATION

This protocol is not involved with ethics approval, and the results will be peer-reviewed and disseminated on a recognised journal.

PROSPERO REGISTRATION NUMBER

CRD42021241820.

Immune Profiling Demonstrates a Common Immune Signature of Delayed Acquired Immunodeficiency in Patients With Various Etiologies of Severe Injury

OBJECTIVES

The host response plays a central role in the pathophysiology of sepsis and severe injuries. So far, no study has comprehensively described the overtime changes of the injury-induced immune profile in a large cohort of critically ill patients with different etiologies.

DESIGN

Prospective observational cohort study.

SETTING

Adult ICU in a University Hospital in Lyon, France.

PATIENTS

Three hundred fifty-three septic, trauma, and surgical patients and 175 healthy volunteers were included in the REAnimation Low Immune Status Marker study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Extensive immune profiling was performed by assessing cellular phenotypes and functions, protein, and messenger RNA levels at days 1-2, 3-4, and 5-7 after inclusion using a panel of 30 standardized immune markers. Using this immunomonitoring panel, no specificity in the immune profile was observed among septic, trauma, and surgical patients. This common injury-induced immune response was characterized by an initial adaptive (i.e., physiologic) response engaging all constituents of the immune system (pro- and anti-inflammatory cytokine releases, and innate and adaptive immune responses) but not associated with increased risk of secondary infections. In contrary, the persistence in a subgroup of patients of profound immune alterations at the end of the first week after admission was associated with increased risk of secondary infections independently of exposure to invasive devices. The combined monitoring of markers of pro-/anti-inflammatory, innate, and adaptive immune responses allowed a better enrichment of patients with risk of secondary infections in the selected population.

CONCLUSIONS

Using REAnimation Low Immune Status Marker immunomonitoring panel, we detected delayed injury-acquired immunodeficiency in a subgroup of severely injured patients independently of primary disease. Critically ill patients' immune status could be captured through the combined monitoring of a common panel of complementary markers of pro-/anti-inflammatory, innate, and adaptive immune responses. Such immune monitoring needs to be incorporated in larger study cohorts with more extensive immune surveillance to develop specific hypothesis allowing for identification of biological systems affecting altered immune function related to late infection in the setting of acute systemic injury.

Invasive Pulmonary Aspergillosis in Hospital and Ventilator-Associated Pneumonias

Pneumonia is the commonest nosocomial infection complicating hospital stay, with both non-ventilated hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) occurring frequently amongst patients in intensive care. Aspergillus is an increasingly recognized pathogen amongst patients with HAP and VAP, and is associated with significantly increased mortality if left untreated.Invasive pulmonary aspergillosis (IPA) was originally identified in patients who had been profoundly immunosuppressed, however, this disease can also occur in patients with relative immunosuppression such as critically ill patients in intensive care unit (ICU). Patients in ICU commonly have several risk factors for IPA, with the inflamed pulmonary environment providing a niche for aspergillus growth.An understanding of the true prevalence of this condition amongst ICU patients, and its specific rate in patients with HAP or VAP is hampered by difficulties in diagnosis. Establishing a definitive diagnosis requires tissue biopsy, which is seldom practical in critically ill patients, so imperfect proxy measures are required. Clinical and radiological findings in ventilated patients are frequently non-specific. The best-established test is galactomannan antigen level in bronchoalveolar lavage fluid, although this must be interpreted in the clinical context as false positive results can occur. Acknowledging these limitations, the best estimates of the prevalence of IPA range from 0.3 to 5% amongst all ICU patients, 12% amongst patients with VAP and 7 to 28% amongst ventilated patients with influenza.Antifungal triazoles including voriconazole are the first-line therapy choice in most cases. Amphotericin has excellent antimold coverage, but a less advantageous side effect profile. Echinocandins are less effective against IPA, but may play a role in rescue therapy, or as an adjuvant to triazole therapy.A high index of suspicion for IPA should be maintained when investigating patients with HAP or VAP, especially when they have specific risk factors or are not responding to appropriate empiric antibacterial therapy.

Improving management and antimicrobial stewardship for bacterial and fungal infections in hospitalized patients with COVID-19

SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection is being one of the most significant challenges of health care systems worldwide. Bacterial and fungal infections in hospitalized patients with coronavirus disease 2019 (COVID-19) are uncommon but consumption of antibiotics and antifungals has increased dramatically during the ongoing pandemic resulting in increased selective pressure for global antimicrobial resistance. Nosocomial bacterial superinfections appear to be more frequent than community-acquired coinfections, particularly among patients admitted to the intensive care unit (ICU) and those receiving immunosuppressive treatment. Fungal infections associated with COVID-19 might be missed or misdiagnosed. Existing and new antimicrobial stewardship (AMS) programmes can be utilized directly in COVID-19 pandemic and are urgently needed to contain the high rates of misdiagnosis and antimicrobial prescription. The aim of this review is to describe the role of bacterial and fungal infections and possible strategies of AMS to use in daily practice for optimal management of COVID-19.

Native Valve Aspergillus Endocarditis in a Non-Neutropenic Immunocompromised Patient on Anti-TNF α Blockers Therapy

Invasive aspergillosis is a rare opportunistic infection mainly occurring in patients with a well-established risk such as neutropenia or conditions that lead to chronically impaired cellular immune responses. Systemic corticosteroids are a well-known risk factor for fungal infections. Recently, reports of invasive aspergillosis in patients treated with monoclonal biologic agents, such as tumor necrosis factor-alpha inhibitors, have been increasing.

We present the case of a 47-year-old female patient with seronegative spondyloarthropathy treated with infliximab and corticosteroids. The patient presented classical symptoms of an acute lower respiratory infection, and she was treated with a β-lactam antibiotic. Infliximab administration was deferred until nine days after clinical recovery. Fourteen days after drug administration, she was admitted with a symptomatic subcortical hematoma in the left parietal region. There was a rapid neurological recovery, and there were no risk factors for haemorrhagic stroke detected. The chest X-ray revealed an oval mass with an air crescent sign, and the CT scan was suggestive of aspergilloma. Bronchoalveolar lavage cytology identified Aspergillus spp. Voriconazole was initiated and, after one month of treatment, the patient was readmitted with a left facial palsy associated with hemiparesis and dysarthria. Laboratory evaluation showed leukocytosis and elevated C-reactive protein. A severe right middle cerebral artery stroke was present on the brain CT scan. Transesophageal echocardiogram revealed large mitral valve vegetation, and the diagnosis of Aspergillus endocarditis with cerebral embolization was made.

Fungal infections are challenging due to the diagnosis infrequency and paucisymptomatic natural history. Despite being crucial in the treatment of autoimmune diseases, immunosuppressive drugs increase the risk of fungal infection. It is extremely important to consider Aspergillus infection in immunosuppressed patients, and the need for prophylaxis in non-neutropenic patients with risk factors should be clarified.

Aspergillosis: Emerging risk groups in critically ill patients

Information on invasive aspergillosis (IA) and other invasive filamentous fungal infections is limited in non-neutropenic patients admitted to the intensive care unit (ICU) and presenting with no classic IA risk factors. This review is based on the critical appraisal of relevant literature, on the authors' own experience and on discussions that took place at a consensus conference. It aims to review risk factors favoring aspergillosis in ICU patients, with a special emphasis on often overlooked or neglected conditions. In the ICU patients, corticosteroid use to treat underlying conditions such as chronic obstructive pulmonary disease (COPD), sepsis, or severe COVID-19, represents a cardinal risk factor for IA. Important additional host risk factors are COPD, decompensated cirrhosis, liver failure, and severe viral pneumonia (influenza, COVID-19). Clinical observations indicate that patients admitted to the ICU because of sepsis or acute respiratory distress syndrome are more likely to develop probable or proven IA, suggesting that sepsis could also be a possible direct risk factor for IA, as could small molecule inhibitors used in oncology. There are no recommendations for prophylaxis in ICU patients; posaconazole mold-active primary prophylaxis is used in some centers according to guidelines for other patient populations and IA treatment in critically ill patients is basically the same as in other patient populations. A combined evaluation of clinical signs and imaging, classical biomarkers such as the GM assay, and fungal cultures examination, remain the best option to assess response to treatment.

LAY SUMMARY

The use of corticosteroids and the presence of co-morbidities such as chronic obstructive pulmonary disease, acute or chronic advanced liver disease, or severe viral pneumonia caused by influenza or Covid-19, may increase the risk of invasive aspergillosis in intensive care unit patients.

Timing of antibiotic therapy in the ICU

Severe or life threatening infections are common among patients in the intensive care unit (ICU). Most infections in the ICU are bacterial or fungal in origin and require antimicrobial therapy for clinical resolution. Antibiotics are the cornerstone of therapy for infected critically ill patients. However, antibiotics are often not optimally administered resulting in less favorable patient outcomes including greater mortality. The timing of antibiotics in patients with life threatening infections including sepsis and septic shock is now recognized as one of the most important determinants of survival for this population. Individuals who have a delay in the administration of antibiotic therapy for serious infections can have a doubling or more in their mortality. Additionally, the timing of an appropriate antibiotic regimen, one that is active against the offending pathogens based on in vitro susceptibility, also influences survival. Thus not only is early empiric antibiotic administration important but the selection of those agents is crucial as well. The duration of antibiotic infusions, especially for β-lactams, can also influence antibiotic efficacy by increasing antimicrobial drug exposure for the offending pathogen. However, due to mounting antibiotic resistance, aggressive antimicrobial de-escalation based on microbiology results is necessary to counterbalance the pressures of early broad-spectrum antibiotic therapy. In this review, we examine time related variables impacting antibiotic optimization as it relates to the treatment of life threatening infections in the ICU. In addition to highlighting the importance of antibiotic timing in the ICU we hope to provide an approach to antimicrobials that also minimizes the unnecessary use of these agents. Such approaches will increasingly be linked to advances in molecular microbiology testing and artificial intelligence/machine learning. Such advances should help identify patients needing empiric antibiotic therapy at an earlier time point as well as the specific antibiotics required in order to avoid unnecessary administration of broad-spectrum antibiotics.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

Invasive aspergillosis in critically ill patients: Review of definitions and diagnostic approaches

Invasive aspergillosis (IA) is an increasingly recognised phenomenon in critically ill patients in the intensive care unit, including in patients with severe influenza and severe coronavirus disease 2019 (COVID-19) infection. To date, there are no consensus criteria on how to define IA in the ICU population, although several criteria are used, including the AspICU criteria and new consensus criteria to categorise COVID-19-associated pulmonary aspergillosis (CAPA). In this review, we describe the epidemiology of IA in critically ill patients, most common definitions used to define IA in this population, and most common clinical specimens obtained for establishing a mycological diagnosis of IA in the critically ill. We also review the most common diagnostic tests used to diagnose IA in this population, and lastly discuss the most common clinical presentation and imaging findings of IA in the critically ill and discuss areas of further needed investigation.

Clinical and microbiological features and outcomes of mucormycosis in critically ill patients

INTRODUCTION

Mucormycosis is a rare invasive fungal infection with high mortality in patients with severe underlying predisposing factors causing immunosuppression. The exact incidence of mucormycosis and the optimal therapeutic approach is difficult to determine, especially in severe cases, due to the rarity of the disease. The new second-generation triazole isavuconazole provides an alternative treatment option which may represent a potential benefit in severe cases.

MATERIALS AND METHODS

A retrospective case series was conducted of patients with a positive laboratory culture for Mucorales and consistent clinical findings who required intensive care treatment. Patient characteristics including demographics, comorbidities, microbiological analysis, specific antifungal therapy and clinical outcome were analysed.

RESULTS

Fifteen critically ill patients with Mucorales detected between 2016 and 2019 were included in this study; the crude mortality rate was 100%. At the time of diagnosis of mucormycosis, 80% of subjects had relevant medical immunosuppression and 53.3% of subjects had neutropenia. Manifestation of mucormycosis was pulmonary in 53.3% of subjects, rhino-orbital in 20% of subjects and disseminated in 26.7% of subjects. Notably, 40% of all patients had received antifungal prophylaxis prior to mucormycosis, mainly with posaconazole due to underlying haematological malignancy, thus possibly representing break-through infections. Antifungal therapy for invasive mucormycosis was administered in 80% of subjects for a median duration of 16 days.

CONCLUSION

In this retrospective cohort analysis of intensive care patients, the prognosis of mucormycosis was extremely poor. An aggressive strategy for diagnosis and treatment is essential for intensive care patients with mucormycosis. There is a need for further research to determine if combination therapy in higher dosages or prompt surgery is beneficial in severe critically ill patients.

Blockade Of PD-1 Attenuated Postsepsis Aspergillosis Via The Activation of IFN-γ and The Dampening of IL-10

BACKGROUND

Nosocomial aspergillosis in patients with sepsis has emerged in the past few years. Blockade of PD-1/PD-L pathway has tended to become a promising therapeutic strategy as it improved the outcome of bacterial sepsis and postsepsis secondary fungal infection. Recently, the controversial effects of PD-1 blockade on infectious diseases, including aspergillosis, have been demonstrated; therefore, the efficacy of anti-PD-1 drug still remains to be elucidated.

METHODS

Cecal ligation and puncture (CLP) was conducted as a mouse sepsis model. Aspergillus fumigatus spores were intravenously inoculated on day 5 post-CLP, when the immune cells succumbed to exhaustion. Amphotericin B was medicated together with or without anti-PD-1 treatment after Aspergillus infection.

RESULTS

Amphotericin B alone was not effective to treat the CLP-mice with secondary aspergillosis. In contrast, antifungal medication with the adjunctive anti-PD-1 treatment attenuated the fungal burdens in blood and internal organs, and improved the survival rate of the mice with secondary aspergillosis. These outcomes of PD-1 blockade were concurring with the enhanced CD86 expression on splenocytes, the augmented serum IFN-γ, and the dampened IL-10. Activated T cells from anti-PD-1-treated mice also highly increased IFN-γ and diminished IL-10 production.

CONCLUSION

The blockade of PD-1 on postsepsis aspergillosis presumably reinvigorated exhausted antigen-presenting cells and T cells by upregulating CD86 expression and IFN-γ production, and dampened IL-10 production, which consequently leaded to the attenuation of secondary aspergillosis. The adjunctive anti-PD-1 therapy may become a promising strategy for the advanced immunotherapy against lethal fungal infection.

Diagnostic value of galactomannan in serum and bronchoalveolar lavage fluid for invasive pulmonary aspergillosis in non-neutropenic patients

OBJECTIVE

To evaluate the diagnostic performance of galactomannan (GM) detection in serum and bronchoalveolar lavage fluid (BALF) for invasive pulmonary aspergillosis (IPA) in non-neutropenic patients.

METHODS

A total of 291 non-neutropenic patients in the Second Xiangya Hospital of Central South University were included. According to the 2019 EORTC/MSG guidelines, all cases were divided into an IPA group (n = 24) and a non-IPA group (n = 267). Receiver operating characteristic (ROC) curves were drawn to compare the diagnostic efficiency of GM detection in BALF and serum.

RESULTS

According to the receiver operating characteristic curves of BALF and serum GM, the areas under the curve were 0.961 and 0.699, respectively. The optimal BALF GM detection was found when the cutoff value was set to 0.87, whereas the sensitivity and specificity were 91.7% and 92.5%, respectively.

CONCLUSIONS

BALF GM detection is more sensitive than serum GM detection for diagnosing IPA, and the optimal cutoff value for BALF GM is 0.87.

Principal-agent theory-based cost and reimbursement structures of isavuconazole treatment in German hospitals

BACKGROUND

Isavuconazole (ISA) is a frequently used antifungal agent for the treatment of invasive fungal diseases (IFDs). However, hospital reimbursement data for ISA is limited.

OBJECTIVES

The primary objective of this study was to analyse the different perspectives of relevant stakeholders and the (dis)incentives for the administration of ISA in Germany. To that aim, the health economic effects of using ISA from a hospital management perspective were analysed.

PATIENTS/METHODS

Based on principal-agent theory (PAT), the perspectives of (a) the patient (principal) as well as (b) physicians, (c) pharmacists and iv. hospital managers (all agents) were analysed. For the evaluation of the cost-containment and reimbursement strategies of ISA, the German diagnosis-related group (G-DRG) system was used.

RESULTS

Hospitals individually negotiating additional payments for innovative treatment procedures (zusatzentgelte [ZE]) within the G-DRG system is a key element of hospital management for the reduction of total healthcare expenditure. Our analysis demonstrated the beneficial role of ISA in healthcare resource utilisation, primarily due to a shortened overall length of hospital stay. Depending on underlying disease, coded G-DRG and ISA formulation, large differences in total reimbursement and the amount of ZE was shown. The PAT demonstrated disincentives for hospital managers to use innovative drugs.

CONCLUSIONS

Based on the PAT, beneficial, detrimental and indifferent perspectives of different stakeholders regarding the usage of ISA were shown. A reduction of bureaucratic hurdles is needed in Germany for the extension of effective and innovative antifungal treatment strategies with ISA.

Pulmonary Aspergillosis in Patients with Suspected Ventilator-associated Pneumonia in UK ICUs

Rationale:Aspergillus infection in patients with suspected ventilator-associated pneumonia remains uncharacterized because of the absence of a disease definition and limited access to sensitive diagnostic tests.Objectives: To estimate the prevalence and outcomes of Aspergillus infection in adults with suspected ventilator-associated pneumonia.Methods: Two prospective UK studies recruited 360 critically ill adults with new or worsening alveolar shadowing on chest X-ray and clinical/hematological parameters supporting suspected ventilator-associated pneumonia. Stored serum and BAL fluid were available from 194 nonneutropenic patients and underwent mycological testing. Patients were categorized as having probable Aspergillus infection using a definition comprising clinical, radiological, and mycological criteria. Mycological criteria included positive histology or microscopy, positive BAL fluid culture, galactomannan optical index of 1 or more in BAL fluid or 0.5 or more in serum.Measurements and Main Results: Of 194 patients evaluated, 24 met the definition of probable Aspergillus infection, giving an estimated prevalence of 12.4% (95% confidence interval, 8.1-17.8). All 24 patients had positive galactomannan in serum (n = 4), BAL fluid (n = 16), or both (n = 4); three patients cultured Aspergillus sp. in BAL fluid. Patients with probable Aspergillus infection had a significantly longer median duration of critical care stay (25.5 vs. 15.5 d, P = 0.02). ICU mortality was numerically higher in this group, although this was not statistically significant (33.3% vs. 22.8%; P = 0.23).Conclusions: The estimated prevalence for probable Aspergillus infection in this geographically dispersed multicenter UK cohort indicates that this condition should be considered when investigating patients with suspected ventilator-associated pneumonia, including patient groups not previously recognized to be at high risk of aspergillosis.

Aspergillus spondylitis: case series and literature review

BACKGROUND

Spinal fungal infections, especially spinal Aspergillus infections, are rare in the clinic. Here, we introduce the clinical features, diagnosis, treatment, and prognoses of 6 cases of Aspergillus spondylitis.

METHODS

We retrospectively analysed the complete clinical data of patients with Aspergillus spondylitis treated in our hospital from January 2013 to January 2020.

RESULTS

Aspergillus fumigatus was isolated in 4 cases, and Aspergillus spp. and Aspergillus niger were isolated in 1 case each. All six patients reported varying degrees of focal spinal pain; one patient reported radiating pain, one patient experienced bowel dysfunction and numbness in both lower limbs, and three patients had fever symptoms. One case involved the thoracic spine, one case involved the thoracolumbar junction, and 4 cases involved the lumbar spine. Three patients were already in an immunosuppressed state, and three patients entered an immunosuppressed state after spinal surgery. All six patients were successfully cured, and five required surgery. Of the 5 patients who underwent surgical treatment, 2 had spinal cord compression symptoms, and 3 had spinal instability. At the end of follow-up, 1 patient reported left back pain and 1 patient reported left limb numbness.

CONCLUSION

The clinical manifestations of Aspergillus spondylitis are non-specific, and the diagnosis depends on typical imaging findings and microbiological and histopathological examination results. When there is no spinal instability, spinal nerve compression symptoms, or progressive deterioration, antifungal therapy alone may be considered. If spinal instability, spinal nerve compression, or epidural abscess formation is present, surgery combined with antifungal therapy is recommended.

Pulmonary Aspergillosis: An Evolving Challenge for Diagnosis and Treatment

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

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.

Invasive pulmonary aspergillosis: comparative analysis in cancer patients with underlying haematologic malignancies versus solid tumours

BACKGROUND

Invasive pulmonary aspergillosis (IPA) is commonly associated with haematologic malignancies but also occurs with solid tumours.

AIM

To compare the diagnostic approaches and therapeutic outcomes for IPA between patients with haematologic malignancies and solid cancers.

METHODS

A retrospective study was conducted evaluating consecutive cases of proven and probable IPA from 2004 to 2016. Patients >18 years of age with an underlying solid tumour, haematologic malignancy, or haematopoietic cell transplantation (HCT) within one year of IPA diagnosis were included.

FINDINGS

Of the 311 patients analysed, 225 had haematologic malignancies and 86 had solid tumours. Patients with solid tumours were more likely to have had chronic obstructive pulmonary disease (COPD) or other pulmonary diseases, have Aspergillus fumigatus infections, and have received radiotherapy before IPA occurrence than were those with haematologic malignancies (all P<0.01). Antifungal monotherapy and voriconazole-based therapy were more often prescribed in the solid group (87% vs 56%, P<0.0001, and 77% vs 53%, P=0.0002, respectively). The median duration of primary antifungal therapy was longer in the solid group (64 days vs 20 days, P<0.0001). Complete or partial response to antifungal therapy was recorded in 66% of the solid group and 40% of the haematologic group (P=0.0001). At 12 weeks, overall mortality was similar in both groups, but IPA-attributable mortality was higher in the haematologic group (30% vs 18%, P=0.04).

CONCLUSIONS

Monotherapy was more often prescribed in patients with solid tumours than in patients with haematologic malignancies. Patients with solid tumours had better antifungal therapy response and lower 12-week IPA-attributable mortality than did those with haematologic malignancies.

Challenges and research priorities to progress the impact of antimicrobial stewardship

Antimicrobial stewardship programmes have been playing an important role in patient care and hospital policies. These programmes are now recognised as formal strategies for curbing the upward trend in antibiotic resistance and for improving the appropriate antimicrobial and antifungal use. The role of such programs in the era of antimicrobial resistance presents several unique challenges and opportunities, most notably in the diagnostic and therapeutic setting. Controversies remain regarding the most effective interventions and the appropriate design to evaluate their impact. In this review, based on rounds of discussion, we explain the most important challenges faced by antibiotic stewardship and antifungal stewardship programmes. We also try to suggest areas for further research.

Prevalence and outcome of invasive pulmonary aspergillosis in critically ill patients with liver cirrhosis: an observational study

Invasive pulmonary aspergillosis (IPA) is an important cause of morbidity/mortality in critically ill patients with endstage liver disease. Therefore, aim of this study is to predict the prevalence and outcome of IPA in critically ill patients with underlying liver cirrhosis and evaluation of the necessity Glactomannan (GM) screening in serum and bronchoalveolar lavage (BAL) in this cohort. In total 12 out of 84 patients (14%) had probable IPA. The mean optical density index (ODI) bronchoalveolar lavage (BAL) GM index was 3.6 ± 1.5 (Range: 1.7–5.7). An overall sensitivity of 90% (95% CI 86–96%) and specificity of 85% (95% CI 81–88%) was found for the BAL GM in IPA. Acute Physiology And Chronic Health Evaluation (APACHE II), sequential organ failure assessment (SOFA) as well the model of endstage liver disease (MELD) score were significantly higher in the probable IPA group as compared to the No IPA group (26 versus 21, p < 0.001 and 14 versus 10, p < 0.044). Length of intensive care unit (ICU) stay was significantly longer in probable IPA patients (16 versus 10 days, p < 0.027) and mortality rate was significantly higher in probable IPA patients (100% versus 65%, p < 0.001) as compared to No IPA patients. APACHE II and MELD score were independently associated with higher mortality rate using multivariate logistic regression (p = 0.025 and p = 0.034). In conclusion, IPA has a relevant impact on outcome. Screening for IPA is indicated, easy to perform and a necessity to improve outcome.

Invasive pulmonary aspergillosis in cirrhotic patients: analysis of a 10-year clinical experience

BACKGROUND

Cirrhosis is not recognised as one of the main risk factors of invasive pulmonary aspergillosis (IPA), although its prevalence is increasing. The aim of our study was to identify factors for IPA in such patients with a positive Aspergillus sp. culture in respiratory samples and to evaluate its impact on outcome.

METHODS

We conducted a monocentric retrospective study between January 2005 and December 2015. All cirrhotic patients hospitalised in our liver ICU with a positive Aspergillus sp. respiratory sample were included. These patients were case-matched with cirrhotic patients without positive Aspergillus respiratory sample. Finally, the patients were classified as having putative aspergillosis or colonisation according to the criteria described previously.

RESULTS

In total, 986 cirrhotic patients were admitted to ICU during the study period. Among these, sixty patients had a positive Aspergillus sp. respiratory sample. Chronic obstructive pulmonary disease (COPD) comorbidity and organ supports were significantly associated with Aspergillus colonisation. Seventeen patients (28%) were diagnosed as proven or putative IPA and 43 were considered as colonised by Aspergillus sp. The median delay between ICU admission and an IPA diagnosis was 2 [2-24] days. Only COPD was predictive of the presence of IPA (OR 6.44; 95% CI 1.43-28.92; p = 0.0151) in patients with a positive Aspergillus sp. culture. The probability of in-hospital mortality was 71% in the IPA group versus 19% in the colonisation group (p = 0.0001).

CONCLUSION

Patients with cirrhosis can be at risk of IPA, especially with COPD. Antifungal agents should be given as soon as possible mainly in cirrhotic patients with COPD.

Point-of-care diagnosis of invasive aspergillosis in non-neutropenic patients: Aspergillus Galactomannan Lateral Flow Assay versus Aspergillus-specific Lateral Flow Device test in bronchoalveolar lavage

BACKGROUND

We compared new Aspergillus Galactomannan Lateral Flow Assay with the newly formatted Aspergillus-specific Lateral Flow device tests for the diagnosis of invasive pulmonary aspergillosis (IPA) in non-neutropenic patients.

METHODS

We performed both tests in 82 bronchoalveolar lavage fluid samples from 82 patients at risk for IPA but without underlying haematologic malignancy. Samples were collected between September 2016 and September 2018 at the University of California San Diego, United States. IPA was classified following two published consensus criteria.

RESULTS

Classification of cases varied widely between the two consensus criteria. When using criteria established for the intensive care unit, 26/82 patients (32%) met criteria for proven or putative IPA. Both point-of-care assays showed sensitivities ranging between 58% and 69%, with specificities between 68% and 75%. Sensitivity increased up to 81% when both tests were combined.

CONCLUSION

The study outlines the need for updated, unified and more broadly applicable consensus definitions for classifying IPA in non-neutropenic patients, a work that is currently in progress. Both point-of-care tests showed comparable performance, with sensitivities and specificities in the 60%-70% range when used alone and increasing to 80% when used in combination. The new point-of-care tests may serve a role at the bedside in those with clinical suspicion of IPA.

Chronic Cavitary Infections Other than Tuberculosis: Clinical Aspects

Lung cavitation may be due to infectious or noninfectious pathologic processes. The latter category includes nonmalignant conditions, such as granulomatosis with polyangiitis, and malignant conditions, such as squamous cell carcinoma of the lung. Infectious etiologies that produce lung cavitation usually cause chronic illness, although some, particularly pyogenic bacteria, may produce acute cavitary disease. Tuberculosis is the most common cause of chronic pulmonary infection with cavitation. The goal of this review was to highlight a selection of the better-known infectious agents, other than tuberculosis, that can cause chronic lung disease with cavitation. Emphasis is placed on the following organisms: nontuberculous mycobacteria, Histoplasma, Blastomyces, Coccidioides, Paracoccidioides, Aspergillus, Burkholderia pseudomallei, Paragonimus westermani, and Rhodococcus equi. These organisms generally produce clinical features and radiologic findings that overlap or mimic those of tuberculosis. In a companion article, we have further emphasized aspects of the same conditions that are more pertinent to radiologists.

Fatal case of cerebral aspergilloma complicated by ventriculitis and bacteremia due to Salmonella species in a sickle cell disease patient

To describe a fatal case of invasive Aspergillus flavus sinusitis in a 43-year old female with sickle cell disease (SCD) complicated by intracerebral aspergilloma and invasive Salmonella infection. Cerebral aspergilloma carries a very high mortality rate. The patient developed post-craniotomy intracerebral hemorrhage at the site of biopsy, Salmonella species sepsis and ventriculitis. She presented with a 2-month history of headache, dizziness, personality and behavioral changes, and vomiting. Initial clinical evaluation raised the suspicion of brain tumor. Brain magnetic resonance imaging revealed a left frontal, thick-walled ring-enhancing lesion with extensive surrounding edema suggestive of a neoplastic lesion, or a contiguous inflammatory or infectious process from the skull base. Despite early diagnosis and appropriate antifungal and surgical management, she eventually died from severe infection and respiratory arrest. In conclusion, invasive aspergillosis should be included in the differential diagnosis of SCD patients with central nervous system (CNS) lesions.

Murine model to follow hyphal development in invasive pulmonary aspergillosis

Aspergillus fumigatus is an opportunistic pathogen, the leading cause of invasive and disseminated aspergillosis in systemic immunocompromised patients, and an important cause of mortality. The aim of the present study was to adapt a pulmonary aspergillosis murine model, to determine pathodynamical parameters quantitatively, and to follow the progression of fungal infection in vivo. The nasal inoculation of Aspergillus conidia in mice previously subjected to immunosuppression with cyclophosphamide (CP) turned out to be a more suitable model than that of immunosuppressed with hydrocortisone (HC). The following parameters were found to correlate quantitatively with the progress of the infection: (i) survival rate, (ii) weight loss of mice, (iii) infected focal plaque size, (iv) hyphal density, (v) hyphal length distribution of A. fumigatus, and the (vi) the histopathological status and scores. These parameters will be essential elements for the development of antifungal drugs and therapies, and important for the investigation of the pathogenicity in different strains of A. fumigatus.