COVID-19 associated with pulmonary aspergillosis: A literature review

Aspergillus fumigatus escape mechanisms from its harsh survival environments

Aspergillus fumigatus is a ubiquitous pathogenic mold and causes several diseases, including mycotoxicosis, allergic reactions, and systemic diseases (invasive aspergillosis), with high mortality rates. In its ecological niche, the fungus has evolved and mastered many reply strategies to resist and survive against negative threats, including harsh environmental stress and deficiency of essential nutrients from natural environments, immunity responses and drug treatments in host, and competition from symbiotic microorganisms. Hence, treating A. fumigatus infection is a growing challenge. In this review, we summarized A. fumigatus reply strategies and escape mechanisms and clarified the main competitive or symbiotic relationships between A. fumigatus, viruses, bacteria, or fungi in host microecology. Additionally, we discussed the contemporary drug repertoire used to treat A. fumigatus and the latest evidence of potential resistance mechanisms. This review provides valuable knowledge which will stimulate further investigations and clinical applications for treating and preventing A. fumigatus infections. KEY POINTS: • Harsh living environment was a great challenge for A. fumigatus survival. • A. fumigatus has evolved multiple strategies to escape host immune responses. • A. fumigatus withstands antifungal drugs via intrinsic escape mechanisms.

AWMF mold guideline "Medical clinical diagnostics for indoor mold exposure" - Update 2023 AWMF Register No. 161/001

None.

Utility of an in-house real-time PCR in whole blood samples as a minimally invasive method for early and accurate diagnosis of invasive mould infections

INTRODUCTION

Invasive mould infections (IMIs) are a leading cause of death in patients with compromised immune systems. Proven invasive mould infection requires detection of a fungus by histopathological analysis of a biopsied specimen, sterile culture, or fungal DNA amplification by PCR in tissue. However, the clinical performance of a PCR assay on blood samples taken from patients suspected of invasive mould disease has not been fully evaluated, particularly for the differential diagnosis of invasive aspergillosis (IA) and invasive Mucormycosis (IM).

OBJECTIVES

To assess the diagnostic utility of our previously validated in-house real-time PCR in blood samples for diagnosis of invasive aspergillosis and mucormycosis in patients with suspected invasive mould infection.

METHODS

All patients with suspected invasive mould infection were prospectively enrolled from May 2021 to July 2021. Conventional fungal diagnosis was performed using tissue and respiratory samples. In-house PCR was performed on blood samples and its diagnostic performance evaluated.

RESULTS

A total of 158 cases of suspected invasive mould infection were enrolled in the study. The sensitivity and specificity of in-house PCR performed on blood samples was found to be 92.5% and 81.4% respectively for diagnosis of probable IA, and 65% and 84.62% respectively for diagnosis of proven and probable IM. It was also able to detect 3 out of 5 cases of possible IM where no other microbiological evidence of IM was obtained.

CONCLUSIONS

This assay could be helpful in minimally invasive diagnosis of IMIs for patients in whom invasive sampling is not feasible, especially as a preliminary or screening test. It can help in early diagnosis, anticipating conventional laboratory confirmation by days or weeks. Possible correlation between fungal load and mortality can help in initiating aggressive treatment for patients with high initial fungal load.

The characteristics of microbiome in the upper respiratory tract of COVID-19 patients

BACKGROUND

Co-infection with other pathogens in coronavirus disease 2019 (COVID-19) patients exacerbates disease severity and impacts patient prognosis. Clarifying the exact pathogens co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is premise of the precise treatment for COVID-19 patients.

METHODS

Sputum samples were collected from 17 patients in the COVID-19 positive group and 18 patients in the COVID-19 negative group. DNA extraction was performed to obtain the total DNA. Sequencing analysis using 16S and ITS rRNA gene was carried out to analyze the composition of bacterial and fungal communities. Meanwhile, all the samples were inoculated for culture.

RESULTS

We did not observe significant differences in bacterial composition between the COVID-19 positive and negative groups. However, a significantly higher abundance of Candida albicans was observed in the upper respiratory tract samples from the COVID-19 positive group compared to the COVID-19 negative group. Moreover, the Candida albicans strains isolated from COVID-19 positive group exhibited impaired secretion of aspartyl proteinases.

CONCLUSION

COVID-19 positive patients demonstrate a notable increase in the abundance of Candida albicans, along with a decrease in the levels of aspartyl proteinases, indicating the alteration of microbiota composition of upper respiratory tract.

Interplay of Cytokines and Chemokines in Aspergillosis

Aspergillosis is a fungal infection caused by various species of Aspergillus, most notably A. fumigatus. This fungus causes a spectrum of diseases, including allergic bronchopulmonary aspergillosis, aspergilloma, chronic pulmonary aspergillosis, and invasive aspergillosis. The clinical manifestations and severity of aspergillosis can vary depending on individual immune status and the specific species of Aspergillus involved. The recognition of Aspergillus involves pathogen-associated molecular patterns (PAMPs) such as glucan, galactomannan, mannose, and conidial surface proteins. These are recognized by the pathogen recognition receptors present on immune cells such as Toll-like receptors (TLR-1,2,3,4, etc.) and C-type lectins (Dectin-1 and Dectin-2). We discuss the roles of cytokines and pathogen recognition in aspergillosis from both the perspective of human and experimental infection. Several cytokines and chemokines have been implicated in the immune response to Aspergillus infection, including interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), CCR4, CCR17, and other interleukins. For example, allergic bronchopulmonary aspergillosis (ABPA) is characterized by Th2 and Th9 cell-type immunity and involves interleukin (IL)-4, IL-5, IL-13, and IL-10. In contrast, it has been observed that invasive aspergillosis involves Th1 and Th17 cell-type immunity via IFN-γ, IL-1, IL-6, and IL-17. These cytokines activate various immune cells and stimulate the production of other immune molecules, such as antimicrobial peptides and reactive oxygen species, which aid in the clearance of the fungal pathogen. Moreover, they help to initiate and coordinate the immune response, recruit immune cells to the site of infection, and promote clearance of the fungus. Insight into the host response from both human and animal studies may aid in understanding the immune response in aspergillosis, possibly leading to harnessing the power of cytokines or cytokine (receptor) antagonists and transforming them into precise immunotherapeutic strategies. This could advance personalized medicine.

Aspergillus fumigatus secretes a protease(s) that displays in silico binding affinity towards the SARS-CoV-2 spike protein and mediates SARS-CoV-2 pseudovirion entry into HEK-293T cells

BACKGROUND

The novel coronavirus disease of 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Data from the COVID-19 clinical control case studies showed that this disease could also manifest in patients with underlying microbial infections such as aspergillosis. The current study aimed to determine if the Aspergillus (A.) fumigatus culture media (i.e., supernatant) possessed protease activity that was sufficient to activate the SARS-CoV-2 spike protein.

METHODS

The supernatant was first analysed for protease activity. Thereafter, it was assessed to determine if it possessed proteolytic activity to cleave a fluorogenic mimetic peptide of the SARS-CoV-2 spike protein that contained the S1/S2 site and a full-length spike protein contained in a SARS-CoV-2 pseudovirion. To complement this, a computer-based tool, HADDOCK, was used to predict if A. fumigatus alkaline protease 1 could bind to the SARS-CoV-2 spike protein.

RESULTS

We show that the supernatant possessed proteolytic activity, and analyses of the molecular docking parameters revealed that A. fumigatus alkaline protease 1 could bind to the spike protein. To confirm the in silico data, it was imperative to provide experimental evidence for enzymatic activity. Here, it was noted that the A. fumigatus supernatant cleaved the mimetic peptide as well as transduced the HEK-293T cells with SARS-CoV-2 pseudovirions.

CONCLUSION

These results suggest that A. fumigatus secretes a protease(s) that activates the SARS-CoV-2 spike protein. Importantly, should these two infectious agents co-occur, there is the potential for A. fumigatus to activate the SARS-CoV-2 spike protein, thus aggravating COVID-19 development.

Risk factors for COVID-19-associated pulmonary aspergillosis: a systematic review and meta-analysis

BACKGROUND

COVID-19-associated pulmonary aspergillosis (CAPA) has been reported to be an emerging and potentially fatal complication of severe COVID-19. However, risk factors for CAPA have not been systematically addressed to date.

METHODS

In this systematic review and meta-analysis to identify factors associated with CAPA, we comprehensively searched five medical databases: Ovid MEDLINE; Ovid Embase; the Cochrane Database of Systematic Reviews; the Cochrane Central Register of Controlled Trials; and the WHO COVID-19 Database. All case-control and cohort studies in adults (aged >18 years) that described at least six cases of CAPA and evaluated any risk factors for CAPA, published from Dec 1, 2019, to July 27, 2023, were screened and assessed for inclusion. Only studies with a control population of COVID-19-positive individuals without aspergillosis were included. Two reviewers independently screened search results and extracted outcome data as summary estimates from eligible studies. The primary outcome was to identify the factors associated with CAPA. Meta-analysis was done with random-effects models, with use of the Mantel-Haenszel method to assess dichotomous outcomes as potential risk factors, or the inverse variance method to assess continuous variables for potential association with CAPA. Publication bias was assessed with funnel plots for factors associated with CAPA. The study is registered with PROSPERO, CRD42022334405.

FINDINGS

Of 3561 records identified, 27 articles were included in the meta-analysis. 6848 patients with COVID-19 were included, of whom 1324 (19·3%) were diagnosed with CAPA. Diagnosis rates of CAPA ranged from 2·5% (14 of 566 patients) to 47·2% (58 of 123). We identified eight risk factors for CAPA. These factors included pre-existing comorbidities of chronic liver disease (odds ratio [OR] 2·70 [95% CI 1·21-6·04], p=0·02; I2=53%), haematological malignancies (OR 2·47 [1·27-4·83], p=0·008; I2=50%), chronic obstructive pulmonary disease (OR 2·00 [1·42-2·83], p<0·0001; I2=26%), and cerebrovascular disease (OR 1·31 [1·01-1·71], p=0·05; I2=46%). Use of invasive mechanical ventilation (OR 2·83; 95% CI 1·88-4·24; p<0·0001; I2=69%), use of renal replacement therapy (OR 2·26 [1·76-2·90], p<0·0001; I2=14%), treatment of COVID-19 with interleukin-6 inhibitors (OR 2·88 [1·52-5·43], p=0·001; I2=89%), and treatment of COVID-19 with corticosteroids (OR 1·88 [1·28-2·77], p=0·001; I2=66%) were also associated with CAPA. Patients with CAPA were typically older than those without CAPA (mean age 66·6 years [SD 3·6] vs 63·5 years [5·3]; mean difference 2·90 [1·48-4·33], p<0·0001; I2=86%). The duration of mechanical ventilation in patients with CAPA was longer than in those without CAPA (n=7 studies; mean duration 19·3 days [8·9] vs 13·5 days [6·8]; mean difference 5·53 days [1·30-9·77], p=0·01; I2=88%). In post-hoc analysis, patients with CAPA had higher all-cause mortality than those without CAPA (n=20 studies; OR 2·65 [2·04-3·45], p<0·0001; I2=51%).

INTERPRETATION

The identified risk factors for CAPA could eventually be addressed with targeted antifungal prophylaxis in patients with severe COVID-19.

FUNDING

None.

The breathtaking world of human respiratory in vitro models: Investigating lung diseases and infections in 3D models, organoids, and lung-on-chip

The COVID-19 pandemic illustrated an urgent need for sophisticated, human tissue models to rapidly test and develop effective treatment options against this newly emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Thus, in particular, the last 3 years faced an extensive boost in respiratory and pulmonary model development. Nowadays, 3D models, organoids and lung-on-chip, respiratory models in perfusion, or precision-cut lung slices are used to study complex research questions in human primary cells. These models provide physiologically relevant systems for studying SARS-CoV-2 and, of course, other respiratory pathogens, but they are, too, suited for studying lung pathologies, such as CF, chronic obstructive pulmonary disease, or asthma, in more detail in terms of viral infection. With these models, the cornerstone has been laid for further advancing the organs by, for example, inclusion of several immune cell types or humoral immune components, combination with other organs in microfluidic organ-on-chip devices, standardization and harmonization of the devices for reliable and reproducible drug and vaccine testing in high throughput.

Accelerating the understanding of Aspergillus terreus: Epidemiology, physiology, immunology and advances

Aspergillus species encompass a variety of infections, ranging from invasive aspergillosis to allergic conditions, contingent upon the immune status of the host. In this spectrum, Aspergillus terreus stands out due to its emergence as a notable pathogen and its intrinsic resistance to amphotericin-B. The significance of Aspergillus-associated infections has witnessed a marked increase in the past few decades, particularly with the increasing number of immunocompromised individuals. The exploration of epidemiology, morphological transitions, immunopathology, and novel treatment approaches such as new antifungal drugs (PC945, olorofim) and combinational therapy using antifungal drugs and phytochemicals (Phytochemicals: quercetin, shikonin, artemisinin), also using immunotherapies to modulate immune response has resulted in better outcomes. Furthermore, in the context COVID-19 era and its aftermath, fungal infections have emerged as a substantial challenge for both immunocompromised and immunocompetent individuals. This is attributed to the use of immune-suppressing therapies during COVID-19 infections and the increase in transplant cases. Consequently, this review aims to provide an updated overview encompassing the epidemiology, germination events, immunopathology, and novel drug treatment strategies against Aspergillus terreus-associated infections.

Therapeutic potential of PANoptosis: innate sensors, inflammasomes, and RIPKs in PANoptosomes

The innate immune system initiates cell death pathways in response to pathogens and cellular stress. Cell death can be either non-lytic (apoptosis) or lytic (PANoptosis, pyroptosis, and necroptosis). PANoptosis has been identified as an inflammatory, lytic cell death pathway driven by caspases and RIPKs that is regulated by PANoptosome complexes, making it distinct from other cell death pathways. Several PANoptosome complexes (including ZBP1-, AIM2-, RIPK1-, and NLRP12-PANoptosomes) have been characterized to date. Furthermore, PANoptosis is implicated in infectious and inflammatory diseases, cancers, and homeostatic perturbations. Therefore, targeting its molecular components offers significant potential for therapeutic development. This review covers PANoptosomes and their assembly, PANoptosome-mediated cell death mechanisms, and ongoing progress in developing therapeutics that target PANoptosis.

CT features of acute COVID-19 and long-term follow-up

Since the first few cases of pneumonia attributed to infection with the highly contagious novel coronavirus 2 (SARs-CoV-2) were detected in Wuhan, China, in December 2019, imaging has proven an invaluable diagnostic tool throughout the resulting global pandemic. This review describes the imaging features of severe pulmonary disease caused by SARs-CoV-2, named COVID-19 by the World Health Organization (WHO), particularly focussing on computed tomography (CT). CT plays an important role in understanding the pathology behind the progression of disease, as well as helping to identify the potential complications of COVID-19 pneumonia and recognising possible alternative or concurrent diagnoses. This review also focusses on follow-up imaging of survivors of COVID-19, which continues to contribute substantially to our understanding of the longer-term pulmonary changes in patients who have survived severe COVID-19 pneumonia.

COVID-19-associated pulmonary aspergillosis (CAPA): identification of Aspergillus species and determination of antifungal susceptibility profiles

Among the co-infectious agents in COVID-19 patients, Aspergillus species cause invasive pulmonary aspergillosis (IPA). IPA is difficult to diagnose and is associated with high morbidity and mortality. This study is aimed at identifying Aspergillus spp. from sputum and tracheal aspirate (TA) samples of COVID-19 patients and at determining their antifungal susceptibility profiles. A total of 50 patients with COVID-19 hospitalized in their intensive care units (ICU) were included in the study. Identification of Aspergillus isolates was performed by phenotypic and molecular methods. ECMM/ISHAM consensus criteria were used for IPA case definitions. The antifungal susceptibility profiles of isolates were determined by the microdilution method. Aspergillus spp. was detected in 35 (70%) of the clinical samples. Among the Aspergillus spp., 20 (57.1%) A. fumigatus, six (17.1%) A. flavus, four (11.4%) A. niger, three (8.6%) A. terreus, and two (5.7%) A. welwitschiae were identified. In general, Aspergillus isolates were susceptible to the tested antifungal agents. In the study, nine patients were diagnosed with possible IPA, 11 patients were diagnosed with probable IPA, and 15 patients were diagnosed with Aspergillus colonization according to the used algorithms. Serum galactomannan antigen positivity was found in 11 of the patients diagnosed with IPA. Our results provide data on the incidence of IPA, identification of Aspergillus spp., and its susceptibility profiles in critically ill COVID-19 patients. Prospective studies are needed for a faster diagnosis or antifungal prophylaxis to manage the poor prognosis of IPA and reduce the risk of mortality.

Mortality and Clinical Outcomes of Aspergillus and COVID-19 Co-infection: A Retrospective Analysis

INTRODUCTION

Patients with coronavirus disease (COVID-19) are more susceptible to secondary infections. Aspergillus co-infection has emerged as one of the most alarming complications in critically ill COVID-19 patients due to the disease itself or the use of immunomodulators and immunosuppressants for treatment. This study aimed to examine the mortality rates and clinical outcomes associated with Aspergillus and COVID-19 co-infection using data obtained from the largest nationwide inpatient sample database in the United States.

METHODS

The National (Nationwide) Inpatient Sample (NIS) database is a vast and openly accessible collection of data that records millions of hospital admissions in the United States. For our research, we utilized the NIS 2020 database to identify adult patients diagnosed with COVID-19 and categorized them based on co-infection with Aspergillus. To examine the NIS database, we utilized various statistical methods such as univariate and multivariate analyses, descriptive statistics, and regression analysis.

RESULTS

Of the 16.7 million patients hospitalized due to COVID-19 infection, 1485 developed Aspergillus co-infection. The demographics showed a predominance of males with 920 males and 565 women. A total of 46% were Caucasians, 17.2% were African-Americans, and 29.5% were Hispanics. The most common comorbidities were chronic pulmonary disease (40.7%), hypertension (41.4%), diabetes with chronic complications (37.7%), leukemia (4.0%), lymphoma (3.7%), and solid tumors (3.7%). Hospital mortality with co-infection was 53.2%, length of stay (LOS) 26.9 days, and economic utilization $138,093 in comparison to patients without co-infection with in-hospital mortality of 13.2%, LOS of 7.9 days, and cost of 21,490. Age-adjusted mortality was 6.6 (confidence interval: 5.9-7.3).

CONCLUSION

Our study indicated that the mortality rate in COVID-19 patients with Aspergillus infection was four-fold higher. Furthermore, comorbidities, such as diabetes mellitus, chronic pulmonary disease, and obesity, have been associated with worse outcomes. Further research is necessary to understand the etiological relationship between Aspergillus infection and COVID-19 in order to develop effective treatment strategies that mitigate the impact of this lethal combination on patient health outcomes.

Characteristics and outcomes for pulmonary aspergillosis in critically ill patients without influenza: A 3-year retrospective study

BACKGROUND

Previous studies have revealed higher mortality rates in patients of severe influenza coinfected with invasive pulmonary aspergillosis (IPA) than in those without the coinfection; nonetheless, the clinical outcome of IPA in critically ill patients without influenza remains unclear.

PATIENTS AND METHODS

This retrospective study was conducted in three institutes. From 2016-2018, all adult patients diagnosed with IPA in the intensive care units (ICUs) were identified. The logistic regression was used to identify the potential risk factors associated with in-hospital mortality in patients with non-influenza IPA. The stratified analysis of IPA patients with and without antifungal therapy was also performed. The final model was established using a forward approach, selecting variables with p-values less than 0.05.

RESULTS

Ninety patients were included during the study period, and 63 (70%) were men. The most common comorbidity was diabetes mellitus (n = 24, 27%), followed by solid cancers (n = 22, 24%). Antifungal therapy was administered to 50 (56%) patients, mostly voriconazole (n = 44). The in-hospital mortality rate was 49% (n = 44). Univariate analysis revealed that the risk factors for mortality included daily steroid dose, APACHE II score, SOFA score, C-reactive protein (CRP) level, carbapenem use, antifungal therapy, and caspofungin use. Multiple regression analysis identified four independent risk factors for mortality: age (Odds ratio [OR], 1.052, p = 0.013), daily steroid dose (OR, 1.057, p = 0.002), APACHE II score (OR, 1.094, p = 0.012), and CRP level (OR, 1.007, p = 0.008). Furthermore, the multivariable analysis identified that more physicians would initiate antifungal therapy for patients with prolonged steroid use (p = 0.001), lower white blood cell count (p = 0.021), and higher SOFA score (p = 0.048). Thus, under the selection bias, the independent risk factors for mortality in the antifungal treatment subgroup were daily steroid dose (OR, 1.046, p = 0.001) and CRP (OR, 1.006, p = 0.018), whereas the independent risk factor for mortality in the untreated group became APACHE II score (OR, 1.232, p = 0.007).

CONCLUSIONS

Patients with IPA had a substantially high mortality. Overall, age, steroid use, APACHE II score, and CRP level were identified as the independent risk factors for mortality in patients in the ICU.

The association between COVID-19 infection and incident atrial fibrillation: results from a retrospective cohort study using a large US commercial insurance database

BACKGROUND

We sought to examine a 1-year incidence of atrial fibrillation (AF) among patients with SARS-CoV-2 virus (COVID-19) in comparison to those with non-COVID-19 acute upper respiratory infection (AURI).

METHODS

Patients with a diagnosis of COVID-19 (in any setting) between April 2020 and June 2021 were identified in Optum Clinformatics. Two comparator cohorts were constructed: an 'AURI pandemic' cohort (AURI diagnosis between April 2020 and June 2021) and an 'AURI prepandemic' cohort (AURI diagnosis between January 2018 and December 2018). One-year incidence of AF was compared among: COVID-19 versus AURI pandemic cohort; COVID-19 versus AURI prepandemic cohort; and AURI pandemic versus AURI prepandemic cohort. For each comparison, we applied a matching weights technique to balance covariates. Logistic regression was used to compare the odds of incident AF among the matched cohorts.

RESULTS

When comparing the matched COVID-19 (n=102 227) cohort with the AURI pandemic (n=102 101) cohort, higher incidence of AF was observed among the COVID-19 cohort (2.2% vs 1.2%; p<0.001; OR 1.83; 95% CI 1.72 to 1.95). Similar findings were observed for the COVID-19 (n=169 687) versus AURI prepandemic (n=169 486) comparison (2.7% vs 1.6%; p<0.001; OR 1.70; 95% CI 1.63 to 1.78). When comparing the AURI pandemic (n=1 26 392) versus AURI prepandemic (n=1 26 394) cohort, no significant differences in incident AF were observed (1.1% vs 1.2%; p=0.133; OR 0.95, 95% CI 0.90 to 1.01).

CONCLUSION

Patients diagnosed with COVID-19 were found to be at a higher risk of incident AF as compared with those with AURI. Timely diagnosis and appropriate treatment of AF may potentially mitigate the burden of AF conferred by COVID-19.

Bacterial Proteases as Potentially Exploitable Modulators of SARS-CoV-2 Infection: Logic from the Literature, Informatics, and Inspiration from the Dog

(1) Background: The COVID-19 pandemic left many intriguing mysteries. Retrospective vulnerability trends tie as strongly to odd demographics as to exposure profiles, genetics, health, or prior medical history. This article documents the importance of nasal microbiome profiles in distinguishing infection rate trends among differentially affected subgroups. (2) Hypothesis: From a detailed literature survey, microbiome profiling experiments, bioinformatics, and molecular simulations, we propose that specific commensal bacterial species in the Pseudomonadales genus confer protection against SARS-CoV-2 infections by expressing proteases that may interfere with the proteolytic priming of the Spike protein. (3) Evidence: Various reports have found elevated Moraxella fractions in the nasal microbiomes of subpopulations with higher resistance to COVID-19 (e.g., adolescents, COVID-19-resistant children, people with strong dietary diversity, and omnivorous canines) and less abundant ones in vulnerable subsets (the elderly, people with narrower diets, carnivorous cats and foxes), along with bioinformatic evidence that Moraxella bacteria express proteases with notable homology to human TMPRSS2. Simulations suggest that these proteases may proteolyze the SARS-CoV-2 spike protein in a manner that interferes with TMPRSS2 priming.

Use of a human small airway epithelial cell line to study the interactions of Aspergillus fumigatus with pulmonary epithelial cells

During the initiation of invasive aspergillosis, inhaled Aspergillus fumigatus conidia are deposited on the epithelial cells lining the bronchi, terminal bronchioles, and alveoli. While the interactions of A. fumigatus with bronchial and type II alveolar cell lines have been investigated in vitro, little is known about the interactions of this fungus with terminal bronchiolar epithelial cells. Using the HSAEC1-KT human small airway epithelial (HSAE) cell line, we developed an in vitro model to study the interaction of two strains of A. fumigatus with these cells. We then compared the interactions of A. fumigatus with the A549 type II alveolar epithelial cell line and the HSAE cell line. We found that A. fumigatus conidia were poorly endocytosed by A549 cells, but avidly endocytosed by HSAE cells. A. fumigatus germlings invaded both cell types by induced endocytosis, but not by active penetration. A549 cell endocytosis of A. fumigatus was independent of fungal viability, more dependent on host microfilaments than microtubules, and induced by A. fumigatus CalA interacting with host cell integrin α5β1. By contrast, HSAE cell endocytosis required fungal viability, was more dependent on microtubules than microfilaments, and did not require CalA or integrin α5β1. HSAE cells were more susceptible than A549 cells to damage caused by direct contact with killed A. fumigatus germlings and by secreted fungal products. In response to A. fumigatus infection, A549 cells secreted a broader profile of cytokines and chemokines than HSAE cells. Taken together, these results demonstrate that studies of HSAE cells provide complementary data to A549 cells and thus represent a useful model for probing the interactions of A. fumigatus with bronchiolar epithelial cells in vitro. Importance During the initiation of invasive aspergillosis, Aspergillus fumigatus interacts with the epithelial cells that line the airways and alveoli. Previous studies of A. fumigatus-epithelial cell interactions in vitro used either large airway epithelial cell lines or the A549 type II alveolar epithelial cell line; the interactions of fungi with terminal bronchiolar epithelial cells were not investigated. Using the TERT-immortalized human small airway epithelial HSAEC1-KT (HSAE) cell line, we developed an in vitro model of the interactions of A. fumigatus with bronchiolar epithelial cells. We discovered that A. fumigatus invades and damages A549 and HSAE cell lines by distinct mechanisms. Also, the proinflammatory responses of the cell lines to A. fumigatus are different. These results provide insight into how A. fumigatus interacts with different types of epithelial cells during invasive aspergillosis and demonstrate that HSAE cells are useful in vitro model for investigating the interactions of this fungus with bronchiolar epithelial cells.

Increased Fungal Infection Mortality Induced by Concurrent Viral Cellular Manipulations

Certain respiratory fungal pathogen mono-infections can cause high mortality rates. Several viral pathogen mono-infections, including influenza viruses and coronaviruses including SARS-CoV-2, can also cause high mortality rates. Concurrent infections by fungal pathogens and highly manipulative viral pathogens can synergistically interact in the respiratory tract to substantially increase their mortality rates. There are at least five viral manipulations which can assist secondary fungal infections. These viral manipulations include the following: (1) inhibiting transcription factors and cytokine expressions, (2) impairing defensive protein expressions, (3) inhibiting defenses by manipulating cellular sensors and signaling pathways, (4) inhibiting defenses by secreting exosomes, and (5) stimulating glucocorticoid synthesis to suppress immune defenses by inhibiting cytokine, chemokine, and adhesion molecule production. The highest mortality respiratory viral pandemics up to now have had substantially boosted mortalities by inducing secondary bacterial pneumonias. However, numerous animal species besides humans are also carriers of endemic infections by viral and multidrug-resistant fungal pathogens. The vast multi-species scope of endemic infection opportunities make it plausible that the pro-fungal manipulations of a respiratory virus can someday evolve to enable a very high mortality rate viral pandemic inducing multidrug-resistant secondary fungal pathogen infections. Since such pandemics can quickly spread world-wide and outrun existing treatments, it would be worthwhile to develop new antifungal treatments well before such a high mortality event occurs.

Diagnosis and Outcomes of Fungal Co-Infections in COVID-19 Infections: A Retrospective Study

The SARS-CoV-2 pandemic has resulted in a public health emergency with unique complications such as the development of fungal co-infections. The diagnosis of fungal infections can be challenging due to confounding imaging studies and difficulty obtaining histopathology. In this retrospective study, 173 patients with COVID-19 receiving antifungal therapy due to concern for fungal co-infection were evaluated. Patient characteristics, clinical outcomes, and the utility of fungal biomarkers were then evaluated for continuation of antifungal therapy. Data were collected from the electronic health record (EPIC) and analyzed using SPSS (version. 28, IBM, Inc., Armonk, NY, USA) Data are presented as mean ± SD or percentages. A total of 56 COVID-19 patients were diagnosed with fungal co-infection and 117 COVID-19 + patients had no fungal infection. Significantly fewer female patients were in the fungal+ group compared to COVID-19 control patients (29% in fungal+ compared to 51% in controls p = 0.005). Fungal diagnostics were all significantly higher in fungal+ patients. These include 1,4-beta-D-glucan (BDG), fungal culture, and bronchoalveolar lavage galactomannan (BAL GM). Intensive care unit hospitalization, mechanical ventilation, and mortality in fungal+ patients with COVID-19 were significantly higher than in control patients. Finally, significantly more fungal+ patients received voriconazole, isavuconazonium, or amphotericin B therapies, whereas control patients received significantly more short-course fluconazole. COVID-19+ patients with fungal co-infection were significantly more likely to be in the ICU and mechanically ventilated, and they result in higher mortality compared to control COVID-19 patients. The use of fungal diagnostics markers were helpful for diagnosis.

Utility of Plasma Microbial Cell-Free DNA Whole-Genome Sequencing for Diagnosis of Invasive Aspergillosis in Patients With Hematologic Malignancy or COVID-19

BACKGROUND

We evaluated the clinical accuracy and utility of whole-genome sequencing (WGS) of plasma microbial cell-free DNA (cfDNA) as a novel noninvasive method in diagnosing invasive aspergillosis (IA) in patients with hematologic malignancy (HM) or coronavirus disease 2019 (COVID-19).

METHODS

Adults with HM or COVID-19 and suspected IA were recruited. IA cases were retrospectively diagnosed according to EORTC/MSG definitions and ECMM/ISHAM criteria for HM and COVID-19 patients, respectively. The results of cfDNA WGS were compared with the conventional diagnosis.

RESULTS

Microbial cfDNA WGS was performed 53 times from 41 participants (19 from HM, 16 from COVID-19, and 7 from the control group). In participants with HM, Aspergillus cfDNA was detected in 100% of proven IA and 91.7% of probable IA cases. In participants with COVID-19, 50.0% of probable IA were positive for Aspergillus in cfDNA WGS. Concordance between Aspergillus cfDNA detection and proven/probable IA conventional diagnosis was significantly higher in participants with HM than in those with COVID-19. IA diagnosed using EORTC/MGS definitions showed significantly high concordance between Aspergillus cfDNA detection and proven/probable IA.

CONCLUSIONS

Aspergillus cfDNA detection strongly correlated with proven/probable IA diagnosed using EORTC/MSG definitions and could be used as an additional diagnostic tool for IA.

A Multiplex PCR Melting-Curve-Analysis-Based Detection Method for the Discrimination of Five Aspergillus Species

Aspergillus mold is a ubiquitously found, airborne pathogen that can cause a variety of diseases from mild to life-threatening in severity. Limitations in diagnostic methods combined with anti-fungal resistance render Aspergillus a global emerging pathogen. In industry, Aspergilli produce toxins, such as aflatoxins, which can cause food spoilage and pose public health risk issues. Here, we report a multiplex qPCR method for the detection and identification of the five most common pathogenic Aspergillus species, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus terreus, and Aspergillus nidulans. Our approach exploits species-specific nucleotide polymorphisms within their ITS genomic regions. This novel assay combines multiplex single-color real time qPCR and melting curve analysis and provides a straight-forward, rapid, and cost-effective detection method that can identify five Aspergillus species simultaneously in a single reaction using only six unlabeled primers. Due to their unique fragment lengths, the resulting amplicons are directly linked to certain Aspergillus species like fingerprints, following either electrophoresis or melting curve analysis. Our method is characterized by high analytical sensitivity and specificity, so it may serve as a useful and inexpensive tool for Aspergillus diagnostic applications both in health care and the food industry.

COVID-19-associated candidiasis and the emerging concern of Candida auris infections

The incidence of COVID-19-associated candidiasis (CAC) is increasing, resulting in a grave outcome among hospitalized patients with COVID-19. The most alarming condition is the increasing incidence of multi-drug resistant Candida auris infections among patients with COVID-19 worldwide. The therapeutic strategy towards CAC caused by common Candida species, such as Candida albicans, Candida tropicalis, and Candida glabrata, is similar to the pre-pandemic era. For non-critically ill patients or those with a low risk of azole resistance, fluconazole remains the drug of choice for candidemia. For critically ill patients, those with a history of recent azole exposure or with a high risk of fluconazole resistance, echinocandins are recommended as the first-line therapy. Several novel therapeutic agents alone or in combination with traditional antifungal agents for candidiasis are potential options in the future. However, for multidrug-resistant C. auris infection, only echinocandins are effective. Infection prevention and control policies, including strict isolation of the patients carrying C. auris and regular screening of non-affected patients, are suggested to prevent the spread of C. auris among patients with COVID-19. Whole-genome sequencing may be used to understand the epidemiology of healthcare-associated candidiasis and to better control and prevent these infections.

A Tale of Two Hospitals: Comparing CAPA Infections in Two ICUs During the Spanish Fourth Pandemic Wave

PURPOSE

COVID-19 associated pulmonary aspergillosis (CAPA) is a new clinical entity linked to SARS-CoV-2 infection that is causing a rise on the risk of complications and mortality, particularly in critical patients.

METHODS

We compared diagnostic and clinical features in two cohorts of patients with severe COVID-19 admitted in the intensive care units (ICU) of two different hospitals in Madrid, Spain, between February and June 2021. Clinical and microbiological relevant aspects for CAPA diagnosis were collected for further classification. CAPA was classified as colonization, possible, probable, proven, and tracheobronchial aspergillosis according to the ECMM/ISHAM consensus, with some modifications to consider tracheobronchial aspirate as sample comparable to non-bronchoscopic lavages (NBL).

RESULTS

56 patients admitted in HULP (Hospital Universitario La Paz) ICU and 61 patients admitted in HEEIZ (Hospital de Emergencias Isabel Zendal) ICU had clinical suspicion of invasive fungal disease in the context of COVID-19 infection. Cultures were positive for Aspergillus spp. in 32 patients. According to 2020 European Confederation of Medical Mycology and the International Society for Human and Animal Mycology (ECMM/ISHAM) consensus, 11 patients were diagnosed with possible CAPA and 10 patients with probable CAPA. Global incidence for CAPA was 6.3%. Global median days between ICU admission and diagnosis was 14 day. Aspergillus fumigatus complex was the main isolated species. Antifungal therapy was used in 75% of patients with CAPA suspicion, with inter-hospital differences in the administered antifungals. Global overall mortality rate for CAPA patients was 66.6% (14/21). All-cause mortality in non-CAPA cohorts were of 26.3% in HULP group (34/129) and 56.8% (104/183) in HEEIZ group.

CONCLUSIONS

There were no significant differences in incidence between the two hospitals, and differences in antifungal therapy did not correlate with differences in mortality, reflecting that both first-line azoles and Amphotericin B could be effective in treating CAPA infections, according to the current guideline indications.

Invasive Fungal Infections Associated with COVID-19

The COVID-19 pandemic caused >6 million deaths worldwide, often from respiratory failure. Complications frequently occurred in hospitalized patients, particularly in the intensive care unit. Among these, fungal infections were a cause of high morbidity and mortality. Invasive aspergillosis, candidiasis and mucormycosis were the most serious of these infections. Risk factors included alterations in immune defense mechanisms by COVID-19 itself, as well as immunosuppression due to various therapies utilized in severely ill patients. Diagnosis was often challenging due to lack of sensitivity of current testing. Outcomes were generally poor, due to significant co-morbidities and delayed diagnosis, with mortality rates >50% in some studies. High index of clinical suspicion is needed to facilitate early diagnosis and initiation of appropriate antifungal therapy.

COVID-19-associated pulmonary aspergillosis in immunocompetent patients: a virtual patient cohort study

The opportunistic fungus Aspergillus fumigatus infects the lungs of immunocompromised hosts, including patients undergoing chemotherapy or organ transplantation. More recently however, immunocompetent patients with severe SARS-CoV2 have been reported to be affected by COVID-19 Associated Pulmonary Aspergillosis (CAPA), in the absence of the conventional risk factors for invasive aspergillosis. This paper explores the hypothesis that contributing causes are the destruction of the lung epithelium permitting colonization by opportunistic pathogens. At the same time, the exhaustion of the immune system, characterized by cytokine storms, apoptosis, and depletion of leukocytes may hinder the response to A. fumigatus infection. The combination of these factors may explain the onset of invasive aspergillosis in immunocompetent patients. We used a previously published computational model of the innate immune response to infection with Aspergillus fumigatus. Variation of model parameters was used to create a virtual patient population. A simulation study of this virtual patient population to test potential causes for co-infection in immunocompetent patients. The two most important factors determining the likelihood of CAPA were the inherent virulence of the fungus and the effectiveness of the neutrophil population, as measured by granule half-life and ability to kill fungal cells. Varying these parameters across the virtual patient population generated a realistic distribution of CAPA phenotypes observed in the literature. Computational models are an effective tool for hypothesis generation. Varying model parameters can be used to create a virtual patient population for identifying candidate mechanisms for phenomena observed in actual patient populations.

Changing Trends in the Incidence and Clinical Features of Pneumocystis jirovecii Pneumonia in Non-HIV Patients before and during the COVID-19 Era and Risk Factors for Mortality between 2016 and 2022

Fungal superinfections have been reported in patients with coronavirus disease 2019 (COVID-19). We analyzed the incidence and clinical characteristics of Pneumocystis jirovecii pneumonia (PCP) in non-human immunodeficiency virus patients at a tertiary hospital between 2016 and 2022 to evaluate the impact of the COVID-19 pandemic on PCP. The study period was divided into pre-COVID-19 and COVID-19 eras based on the pandemic declaration by the World Health Organization. Among the 113 patients included, the incidence of PCP in the COVID-19 era (37/1000 patient-years) was significantly higher than that in the pre-COVID-19 era (13.1/1000 patient-years) (p < 0.001). Co-infection with invasive pulmonary aspergillosis (IPA) also increased (2.4% vs. 18.3%, p = 0.013). Independent risk factors for PCP-related mortality were previous glucocorticoid use, hypoxemia, acute kidney injury, and IPA co-infection. Risk factors for IPA in patients with PCP included previous use of tyrosine kinase inhibitors, COVID-19 infection within 30 days, leukopenia, and intensive care unit admission. In the COVID-19 era, 12 (16.9%) patients with PCP had a history of COVID-19 infection within 90 days; however, infection was not associated with mortality. Active evaluation of patients with suspected PCP and assessment of IPA co-infection risk may help improve the outcomes of patients with PCP.

The potential role of plant secondary metabolites on antifungal and immunomodulatory effect

With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a serious threat to global public health security. Moreover, the evolution of fungal resistance to existing antifungal drugs is on the rise. To address these issues, the development of new antifungal drugs or fungal inhibitors needs to be targeted urgently. Plant secondary metabolites are characterized by a wide variety of chemical structures, low price, high availability, high antimicrobial activity, and few side effects. Therefore, plant secondary metabolites may be important resources for the identification and development of novel antifungal drugs. However, there are few studies to summarize those contents. In this review, the antifungal modes of action of plant secondary metabolites toward different types of fungi and fungal infections are covered, as well as highlighting immunomodulatory effects on the human body. This review of the literature should lay the foundation for research into new antifungal drugs and the discovery of new targets. KEY POINTS: • Immunocompromised patients who are infected the drug-resistant fungi are increasing. • Plant secondary metabolites toward various fungal targets are covered. • Plant secondary metabolites with immunomodulatory effect are verified in vivo.

The Impact of the COVID-19 Pandemic on Antimicrobial Resistance and Management of Bloodstream Infections

INTRODUCTION

The pressure of the COVID-19 pandemic on healthcare systems led to limited roles of infectious diseases services, increased rates of irrational use of antimicrobials, and incidence of infections by multidrug-resistant microorganisms. The aim of the present study is to evaluate the incidence of antimicrobial resistance and the management of bloodstream infections before and during the COVID-19 pandemic at the University General Hospital of Alexandroupolis (Greece).

MATERIALS AND METHODS

This is a retrospective study conducted from January 2018 to December 2022. Data were collected from the University Microbiology Laboratory per semester regarding the isolated strains of Gram-positive and -negative bacteria in blood cultures and respiratory samples in hospitalized patients in medical and surgical wards and in the intensive care unit (ICU). Additionally, bloodstream infections with requested infectious disease consultations were reported (n = 400), determining whether these were carried out via telephone contact or at the patient's bedside. Demographic data, comorbidities, focus of infection, antimicrobial regimen, duration of treatment, length of hospitalization, and clinical outcome were analyzed.

RESULTS

A total of 4569 strains of Gram-positive and -negative bacteria were isolated. An increasing trend was reported compared to the pre-pandemic period in the incidence of resistant Gram-negative bacteria, particularly in ICUs. Prior antimicrobial use and the rate of hospital-acquired infections were increased significantly during the pandemic. In the pre-pandemic period 2018-2019, a total of 246 infectious disease consultations were carried out, while during the period 2020-2022, the number was 154, with the percentage of telephone consultations 15% and 76%, respectively. Detection of the source of infection and timely administration of appropriate antimicrobial agents were more frequently recorded before the pandemic, and 28-day mortality was significantly reduced in cases with bedside consultations.

CONCLUSION

The empowering of infectious disease surveillance programs and committees, rational use of antimicrobials agents, and bedside infectious disease consultations are vital in order to reduce the impact of infections caused by multidrug-resistant strains.

Clinical Features of SARS-CoV-2 Infection in Patients Undergoing Solid-Organ Transplant: Baskent University Experience

OBJECTIVES

The clinical features and treatment approaches, outcomes, and mortality predictors of COVID-19 in solid-organ transplant recipients have not been well defined. This study investigated the clinical features of COVID-19 infection in solid-organ transplant recipients at our center in Turkey.

MATERIALS AND METHODS

Our study included 23 solidorgan transplant recipients and 336 nontransplant individuals (143 previously healthy and 193 patients with at least 1 comorbidity) who were hospitalized due to COVID-19 disease in our hospital between March 2020 and January 2021. Demographic, clinical, and laboratory data of patients were compared. We used SPSS version 20.0 for statistical analysis. All groups were compared using chi-square and Mann-Whitney U tests. P <.05 was considered statistically significant.

RESULTS

Mean age of solid-organ transplant recipients was 49.8 ± 13.7 years (78.3% men, 21.7% women). Among the 23 recipients, 17 (73.9%) were kidney and 6 (26.1%) were liver transplant recipients. Among nontransplant individuals, 88.7% (n = 298) had mild/moderate disease and 11.3% (n = 38) had severe disease. Among transplant recipients, 78.3% (n = 18) had mild/moderate disease and 21.7% (n = 5) had severe disease (P = .224). Transplant recipients had greater requirements for nasal oxygen (P = .005) and noninvasive mechanical ventilation (P = .003) and had longer length of intensive care unit stay (P = .030) than nontransplant individuals. No difference was found between the 2 groups in terms of mortality (P = .439). However, a subgroup analysis showed increased mortality in transplant recipients versus previously healthy patients with COVID-19 (P <.05). Secondary infections were major causes of mortality in transplant recipients.

CONCLUSIONS

COVID-19 infection resulted in higher mortality in solid-organ transplant recipients versus that shown in healthy patients. More attention on secondary infections is needed in transplant recipients to reduce mortality.

Use of a human small airway epithelial cell line to study the interactions of Aspergillus fumigatus with pulmonary epithelial cells

During the initiation of invasive aspergillosis, inhaled Aspergillus fumigatus conidia are deposited on the epithelial cells lining the bronchi, terminal bronchioles, and alveoli. While the interactions of A. fumigatus with bronchial and type II alveolar cell lines have been investigated in vitro , little is known about the interactions of this fungus with terminal bronchiolar epithelial cells. We compared the interactions of A. fumigatus with the A549 type II alveolar epithelial cell line and the HSAEC1-KT human small airway epithelial (HSAE) cell line. We found that A. fumigatus conidia were poorly endocytosed by A549 cells, but avidly endocytosed by HSAE cells. A. fumigatus germlings invaded both cell types by induced endocytosis, but not by active penetration. A549 cell endocytosis of A. fumigatus was independent of fungal viability, more dependent on host microfilaments than microtubules, and induced by A. fumigatus CalA interacting with host cell integrin α5β1. By contrast, HSAE cell endocytosis required fungal viability, was more dependent on microtubules than microfilaments, and did not require CalA or integrin α5β1. HSAE cells were more susceptible than A549 cells to damage caused by direct contact with killed A. fumigatus germlings and by secreted fungal products. In response to A. fumigatus infection, A549 cells secreted a broader profile of cytokines and chemokines than HSAE cells. Taken together, these results demonstrate that studies of HSAE cells provide complementary data to A549 cells and thus represent a useful model for probing the interactions of A. fumigatus with bronchiolar epithelial cells in vitro .

Importance

During the initiation of invasive aspergillosis, Aspergillus fumigatus invades, damages, and stimulates the epithelial cells that line the airways and alveoli. Previous studies of A. fumigatus - epithelial cell interactions in vitro have used either large airway epithelial cell lines or the A549 type II alveolar epithelial cell line. The interactions of fungi with terminal bronchiolar epithelial cells have not been investigated. Here, we compared the interactions of A. fumigatus with A549 cells and the Tert-immortalized human small airway epithelial HSAEC1-KT (HSAE) cell line. We discovered that A. fumigatus invades and damages these two cell lines by distinct mechanisms. Also, the proinflammatory responses of the cell lines to A. fumigatus are different. These results provide insight into how A. fumigatus interacts with different types of epithelial cells during invasive aspergillosis and demonstrate that HSAE cells are useful in vitro model for investigating the interactions of this fungus with bronchiolar epithelial cells.

Can photocatalysis help in the fight against COVID-19 pandemic?

Mould fungi are serious threats to humans and animals (allergen) and might be the main cause of COVID-19-associated pulmonary aspergillosis. The common methods of disinfection are not highly effective against fungi due to the high resistance of fungal spores. Recently, photocatalysis has attracted significant attention towards antimicrobial action. Outstanding properties of titania photocatalysts have already been used in many areas, e.g., for building materials, air conditioner filters, and air purifiers. Here, the efficiency of photocatalytic methods to remove fungi and bacteria (risk factors for Severe Acute Respiratory Syndrome Coronavirus 2 co-infection) is presented. Based on the relevant literature and own experience, there is no doubt that photocatalysis might help in the fight against microorganisms, and thus prevent the severity of COVID-19 pandemic.

Optimal control for co-infection with COVID-19-Associated Pulmonary Aspergillosis in ICU patients with environmental contamination

In this paper, we propose a mathematical model for COVID-19-Associated Pulmonary Aspergillosis (CAPA) co-infection, that enables the study of relationship between prevention and treatment. The next generation matrix is employed to find the reproduction number. We enhanced the co-infection model by incorporating time-dependent controls as interventions based on Pontryagin's maximum principle in obtaining the necessary conditions for optimal control. Finally, we perform numerical experiments with different control groups to assess the elimination of infection. In numerical results, transmission prevention control, treatment controls, and environmental disinfection control provide the best chance of preventing the spread of diseases more rapidly than any other combination of controls.

A Case of Fulminant Fusobacterium necrophorum Bacteremia Secondary to Non-severe COVID-19

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is more infectious than the previous variants but less severe; more patients are being followed up without hospitalization. Identification of patients with severe disease symptoms as early as possible and prompt initiation of treatment are crucial. A case of a 19-year-old man with mild COVID-19 is described in this report. He died of a secondary infection with Fusobacterium necrophorum bacteremia and a progressive hemorrhagic disorder. The diagnosis was made based on the clinical course and needle necropsy results. In non-severe COVID-19 patients, rapid deterioration of the disease symptoms requiring emergency treatment should lead to suspicion of additional fatal infections with similar clinical symptoms.

Comparison of Multi-locus Genotypes Detected in Aspergillus fumigatus Isolated from COVID Associated Pulmonary Aspergillosis (CAPA) and from Other Clinical and Environmental Sources

Background: Aspergillus fumigatus is a saprophytic fungus, ubiquitous in the environment and responsible for causing infections, some of them severe invasive infections. The high morbidity and mortality, together with the increasing burden of triazole-resistant isolates and the emergence of new risk groups, namely COVID-19 patients, have raised a crescent awareness of the need to better comprehend the dynamics of this fungus. The understanding of the epidemiology of this fungus, especially of CAPA isolates, allows a better understanding of the interactions of the fungus in the environment and the human body. Methods: In the present study, the M3 markers of the STRAf assay were used as a robust typing technique to understand the connection between CAPA isolates and isolates from different sources (environmental and clinical-human and animal). Results: Of 100 viable isolates that were analyzed, 85 genotypes were found, 77 of which were unique. Some isolates from different sources presented the same genotype. Microsatellite genotypes obtained from A. fumigatus isolates from COVID+ patients were all unique, not being found in any other isolates of the present study or even in other isolates deposited in a worldwide database; these same isolates were heterogeneously distributed among the other isolates. Conclusions: Isolates from CAPA patients revealed high heterogeneity of multi-locus genotypes. A genotype more commonly associated with COVID-19 infections does not appear to exist.

Filamentous Fungi Infections: Yet Another Victim of COVID-19?

Filamentous fungi have always been a matter of concern in the medical field, but nowadays, due to an increase in the risk factors and the added infections with the SARS-CoV-2 virus, they are slowly but surely emerging as a dangerous health threat worldwide. Our study aims to estimate the incidence of mold infections in central Romania, as well as assess the impact the pandemic had on them while evaluating other parameters such as age, associated bacterial and fungal infections and comorbidities. Purulent discharge and respiratory secretion specimens were collected and analyzed over a period of 10 years. A total of 68 samples tested positive for molds, with an increased number of positive samples during the pandemic. The highest number of specimens came from the outpatient department, followed by medical wards, with the most common filamentous fungus being Aspergillus section Flavi. Associated diseases included affections of the respiratory system, followed by the cardiovascular system and people who suffered from a viral infection with SARS-CoV-2, and they were mostly present in seniors. The most common associated infections were with Staphylococcus aureus and Candida nonalbicans. A statistically significant correlation was found between the association of mold infection and SARS-CoV-2 and an increase in mortality.

Pneumocystis pneumonia in COVID-19 patients: A comprehensive review

The admitted patients of intensive care units with coronavirus disease 2019 (COVID-19) meet the challenges of subsequent infections. Opportunistic fungal infections such as Pneumocystis pneumonia (PCP) are among the important factors in the context of COVID-19 patients affecting illness severity and mortality. We reviewed the literature on COVID-19 patients with PCP to identify features of this infection. Although studies confirmed at least the presence of one immunosuppressive condition in half of PCP patients, this disease can also occur in immunocompetent patients who developed the immunosuppressive condition during Covid-19 treatment. The major risk factors associated with COVID-19 patients with PCP can be considered low lymphocyte counts and corticosteroid therapy. Diagnostic and treatment options are complicated by the overlapping clinical and radiologic characteristics of PCP and COVID-19 pneumonia. Therefore, physicians should comprehensively evaluate high-risk patients for PCP prophylaxis.

Coronavirus disease 2019 rebounds following nirmatrelvir/ritonavir treatment

Nirmatrelvir/ritonavir (NMV-r) is an effective anti-SARS-CoV-2 agent and has been recommended in the treatment of nonhospitalized patients with COVID-19. In rare occasions, some patients experience virologic and symptomatic rebound after initial resolution, which we call COVID-19 rebound after NMV-r. Although COVID rebound can also occur after molnupiravir treatment or even no antiviral treatment, we have more serious concern about the rebound after NMV-r, which remains the most effective antiviral. Due to a lack of information about its frequency, mechanism, outcomes, and management, we conducted this review to provide comprehensive and updated information to address these questions. Based on the limited evidence, the incidence of COVID-19 rebound after NMV-r was less than 2%, and most cases developed 5-15 days after initiating NMV-r treatment. Almost all reported cases had mild symptoms, and the clinical condition gradually subsided without additional treatment. Overall, the clinical outcome was favorable, and only a small number of patients required emergency department visits or hospitalization. Regarding virologic rebound, culturable SARS-CoV-2 with possible transmission was observed, so re-isolation may be needed.

Aspergillosis ball graft as complication of Covid-19 infection: Case report

Invasive pulmonary aspergillosis is a severe presentation of aspergillosis fungal infection, with a high mortality rate. Many Covid-19-associated pulmonary aspergillosis cases have been described in the literature giving rise to a major dilemma for physicians: discriminate a simple colonization from an invasive infection. In this paper, we will describe the case of a 40-year-old immunocompetent man with no medical history was admitted to the intensive care unit for Covid-19 infection with lung damage initially estimated at 50%-75%. Two weeks later, patient condition got worse, with a thoracic CT showing a newly developed, well limited lung cavitation indicative of an aspergillosis fungus ball.

Gastric Aspergillosis in a COVID-19 Patient

The SARS-CoV-2 virus, which causes Coronavirus-19 infection (COVID-19), frequently elicits the development of depressed immunity, therefore, opportunistic infections. Opportunistic organisms are commonly present in the human body without causing critical illness. However, they can also lead to pathologic illness when a person is immunocompromised. Aspergillosis is among the many opportunistic infections. Even though this infection primarily involves the respiratory system and is less likely to be found in the gastrointestinal tract, we report a case of a COVID-19 individual that developed massive gastrointestinal bleeding whose condition deteriorated, and the pathological examination revealed gastric aspergillosis. Although not common, gastric aspergillosis should be considered while treating patients with COVID-19 who present gastrointestinal symptoms.

Transcriptome analysis reveals increased abundance and diversity of opportunistic fungal pathogens in nasopharyngeal tract of COVID-19 patients

We previously reported that SARS-CoV-2 infection reduces human nasopharyngeal commensal microbiomes (bacteria, archaea and commensal respiratory viruses) with inclusion of pathobionts. This study aimed to assess the possible changes in the abundance and diversity of resident mycobiome in the nasopharyngeal tract (NT) of humans due to SARS-CoV-2 infections. Twenty-two (n = 22) nasopharyngeal swab samples (including COVID-19 = 8, Recovered = 7, and Healthy = 7) were collected for RNA-sequencing followed by taxonomic profiling of mycobiome. Our analyses indicate that SARS-CoV-2 infection significantly increased (p < 0.05, Wilcoxon test) the population and diversity of fungi in the NT with inclusion of a high proportion of opportunistic pathogens. We detected 863 fungal species including 533, 445, and 188 species in COVID-19, Recovered, and Healthy individuals, respectively that indicate a distinct mycobiome dysbiosis due to the SARS-CoV-2 infection. Remarkably, 37% of the fungal species were exclusively associated with SARS-CoV-2 infection, where S. cerevisiae (88.62%) and Phaffia rhodozyma (10.30%) were two top abundant species. Likewise, Recovered humans NT samples were predominated by Aspergillus penicillioides (36.64%), A. keveii (23.36%), A. oryzae (10.05%) and A. pseudoglaucus (4.42%). Conversely, Nannochloropsis oceanica (47.93%), Saccharomyces pastorianus (34.42%), and S. cerevisiae (2.80%) were the top abundant fungal species in Healthy controls nasal swabs. Importantly, 16% commensal fungal species found in the Healthy controls were not detected in either COVID-19 patients or when they were cured from COVID-19 (Recovered). We also detected several altered metabolic pathways correlated with the dysbiosis of fungal mycobiota in COVID-19 patients. Our results suggest that SARS-CoV-2 infection causes significant dysbiosis of mycobiome and related metabolic functions possibly play a determining role in the progression of SARS-CoV-2 pathogenesis. These findings might be helpful for developing mycobiome-based diagnostics, and also devising appropriate therapeutic regimens including antifungal drugs for prevention and control of concurrent fungal coinfections in COVID-19 patients.

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

The clinical course and outcome of COVID-19 are highly variable, ranging from asymptomatic infections to severe disease and death. Understanding the risk factors of severe COVID-19 is relevant both in the clinical setting and at the epidemiological level. Here, we provide an overview of host, viral and environmental factors that have been shown or (in some cases) hypothesized to be associated with severe clinical outcomes. The factors considered in detail include the age and frailty, genetic polymorphisms, biological sex (and pregnancy), co- and superinfections, non-communicable comorbidities, immunological history, microbiota, and lifestyle of the patient; viral genetic variation and infecting dose; socioeconomic factors; and air pollution. For each category, we compile (sometimes conflicting) evidence for the association of the factor with COVID-19 outcomes (including the strength of the effect) and outline possible action mechanisms. We also discuss the complex interactions between the various risk factors.

COVID-19-associated pulmonary aspergillosis in immunocompetent patients: A virtual patient cohort study

Purpose

The opportunistic fungus Aspergillus fumigatus infects the lungs of immunocompromised hosts, including patients undergoing chemotherapy or organ transplantation. More recently however, immunocompetent patients with severe SARS-CoV2 have been reported to be affected by COVID-19 Associated Pulmonary Aspergillosis (CAPA), in the absence of the conventional risk factors for invasive aspergillosis. This paper explores the hypothesis that contributing causes are the destruction of the lung epithelium permitting colonization by opportunistic pathogens. At the same time, the exhaustion of the immune system, characterized by cytokine storms, apoptosis, and depletion of leukocytes may hinder the response to A. fumigatus infection. The combination of these factors may explain the onset of invasive aspergillosis in immunocompetent patients.

Methods

We used a previously published computational model of the innate immune response to infection with Aspergillus fumigatus . Variation of model parameters was used to create a virtual patient population. A simulation study of this virtual patient population to test potential causes for co-infection in immunocompetent patients.

Results

The two most important factors determining the likelihood of CAPA were the inherent virulence of the fungus and the effectiveness of the neutrophil population, as measured by granule half-life and ability to kill fungal cells. Varying these parameters across the virtual patient population generated a realistic distribution of CAPA phenotypes observed in the literature.

Conclusions

Computational models are an effective tool for hypothesis generation. Varying model parameters can be used to create a virtual patient population for identifying candidate mechanisms for phenomena observed in actual patient populations.

Innate and Adaptive Immune Responses Induced by Aspergillus fumigatus Conidia and Hyphae

Previous research indicated that hyphae of Aspergillus fumigatus (A. fumigatus) rather than conidia could successfully build a pulmonary aspergillosis model in immunocompetent mice. In this study, we compared the immune responses induced by hyphae and conidia to explore the possible mechanism of this striking phenomenon. Herein, a novel method was designed and adopted to quantify hyphal fragments. Murine macrophages RAW264.7 and human peripheral blood mononuclear cells were stimulated by A. fumigatus hyphae and conidia in vitro, respectively, and then immunological reactions were measured. Male C57BL/6 mice were challenged with conidia and hyphae through intratracheal inoculation. Dynamic conditions of mice were recorded, and RNA-seq measured corresponding immune responses. The results of the study confirmed that hyphae could induce more intensive inflammation than conidia in vitro and in vivo. However, macrophages revealed a higher production of ROS and M1 polarisation in response to conidia stimuli. Additionally, conidia could promote Th1 cell differentiation, while hyphae could increase the CD4/CD8 ratio. RNA-seq validated the fact that those multiple immunologically relevant pathways were more strongly activated by hyphae than conidia, which also promoted Th2 cell differentiation and suppressed Th1 signalling. Both hyphae and conidia could activate Th17 signalling. In general, conidia and hyphae induced distinctly different host immune responses, and the immune responses induced by conidia played a better protective effect. Therefore, the unique function of hyphae in the spread and infection of Aspergillus should be emphasised, and more research is required to clarify the underlying mechanisms for better understanding and management of aspergillosis.

A Case Series Demonstrating the Difficulties in Diagnosing COVID-19 Associated Pulmonary Aspergillus

Many bacterial, viral, and fungal co-infections have been reported with COVID-19-associated acute respiratory distress syndrome (ARDS). Invasive Aspergillosis has been described with COVID-19 ARDS. However, it continues to evade diagnosis in critically ill patients admitted to the intensive care unit (ICU). The difficulty is discerning an actual infection from colonization. Unfortunately, a timely diagnosis is crucial since COVID-19-associated pulmonary Aspergillus (CAPA) has high morbidity and mortality. We present three ICU cases of CAPA to illustrate the difficulty in diagnosing and treating the disease. We hope to bring awareness and improve patient outcomes of CAPA.

HIF1-α upregulation induces proinflammatory factors to boost host killing capacity after Aspergillus fumigatus exposure

Aims: HIF1-α is an important transcription factor in the regulation of the immune response. The protective function of HIF1-α in the host epithelial immune response to Aspergillus fumigatus requires further clarification. Methods: In this study we demonstrated the effect of upregulation of HIF1-α expression in A549 cells and mouse airway cells exposed to A. fumigatus in vivo. Results: The killing capacity was enhanced by boosting proinflammatory factors both in vitro and in vivo. Moreover, airway inflammation was reduced in the HIF1-α-upregulated mice. Conclusion: We identified a protective role for HIF1-α in anti-A. fumigatus immunity. Modulation of HIF1-α might be a target for the development of aspergillosis therapy.

A Laboratory-Based Study on Multiple Biomarker Testing in the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis (CAPA): Real-Life Data

(1) Background: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) raises concerns to contribute to an increased mortality. The incidence of CAPA varies widely within hospitals and countries, partly because of difficulties in obtaining a reliable diagnosis. (2) Methods: Here, we assessed Aspergillus culture-positive and culture-negative respiratory tract specimens via direct fungal microscopy (gold standard) and compared the results with galactomannan enzyme immunoassay (GM-EIA) and Aspergillus PCR. (3) Results: 241 respiratory samples from patients suffering from SARS-CoV-2 pneumonia were evaluated. Results showed both diagnostic tools, Aspergillus PCR and GM-EIA, to be positive or negative displaying a sensitivity of 0.90, a specificity of 0.77, a negative predictive value (NPV) of 0.95, and a positive predictive value (PPV) of 0.58 in Aspergillus sp. culture and microscopic-positive specimens. Non-bronchoalveolar lavage (BAL) samples, obtained within a few days from the same patient, showed a high frequency of intermittent positive or negative GM-EIA or Aspergillus PCR results. Positivity of a single biomarker is insufficient for a proper diagnosis. A broad spectrum of Aspergillus species was detected. (4) Conclusions: Our study highlights the challenges of combined biomarker testing as part of diagnosing CAPA. From the results presented, we highly recommend the additional performance of direct microscopy in respiratory specimens to avoid overestimation of fungal infections by applying biomarkers.