Invasive Aspergillosis in the Intensive Care Unit

Biomarkers in pulmonary infections: a clinical approach

Severe acute respiratory infections, such as community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia, constitute frequent and lethal pulmonary infections in the intensive care unit (ICU). Despite optimal management with early appropriate empiric antimicrobial therapy and adequate supportive care, mortality remains high, in part attributable to the aging, growing number of comorbidities, and rising rates of multidrug resistance pathogens. Biomarkers have the potential to offer additional information that may further improve the management and outcome of pulmonary infections. Available pathogen-specific biomarkers, for example, Streptococcus pneumoniae urinary antigen test and galactomannan, can be helpful in the microbiologic diagnosis of pulmonary infection in ICU patients, improving the timing and appropriateness of empiric antimicrobial therapy since these tests have a short turnaround time in comparison to classic microbiology. On the other hand, host-response biomarkers, for example, C-reactive protein and procalcitonin, used in conjunction with the clinical data, may be useful in the diagnosis and prediction of pulmonary infections, monitoring the response to treatment, and guiding duration of antimicrobial therapy. The assessment of serial measurements overtime, kinetics of biomarkers, is more informative than a single value. The appropriate utilization of accurate pathogen-specific and host-response biomarkers may benefit clinical decision-making at the bedside and optimize antimicrobial stewardship.

Fungal infections in immunocompromised critically ill patients

Diverse pathogenic fungi can produce severe infections in immunocompromised patients, thereby justifying intensive care unit (ICU) admissions. In some cases, the infections can develop in immunocompromised patients who were previously admitted to the ICU. Aspergillus spp., Pneumocystis jirovecii, Candida spp., and Mucorales are the fungi that are most frequently involved in these infections. Diagnosis continues to be challenging because symptoms and signs are unspecific. Herein, we provide an in-depth review about the diagnosis, with emphasis on recent advances, and treatment of these invasive fungal infections in the ICU setting.

Invasive pulmonary aspergillosis among patients with severe community-acquired pneumonia and influenza in ICUs: a retrospective cohort study

RATIONALE

The prevalence, clinical characteristics, and outcomes of invasive pulmonary aspergillosis in patients with severe community-acquired pneumonia (CAP) in intensive care units remain underestimated because of the lack of a disease-recognition scheme and the inadequacy of diagnostic tests.

OBJECTIVES

To identify the prevalence, risk factors, and outcomes of severe CAP complicated with invasive pulmonary aspergillosis (IPA) in intensive care units (ICUs).

METHODS

We conducted a retrospective cohort study including recruited 311 ICU-hospitalized patients with severe CAP without influenza or with influenza. Bronchoalveolar lavage fluid (BALF) samples were from all patients and subjected to mycological testing. Patients were categorized as having proven or probable Aspergillus infection using a modified form of the AspICU algorithm comprising clinical, radiological, and mycological criteria.

MEASUREMENTS AND MAIN RESULTS

Of the 252 patients with severe CAP and 59 influenza patients evaluated, 24 met the diagnostic criteria for proven or probable Aspergillus infection in the CAP group and 9 patients in the influenza group, giving estimated prevalence values of 9.5% and 15.3%, respectively. COPD and the use of inhaled corticosteroids were independent risk factors for IPA. IPA in patients with severe CAP was significantly associated with the duration of mechanical support, the length of ICU stay, and the 28-day mortality.

CONCLUSIONS

An aggressive diagnostic approach for IPA patients with severe CAP and not only influenza or COVID-19 should be pursued. Further randomized controlled trials need to evaluate the timing, safety, and efficacy of antifungal therapy in reducing IPA incidence and improving clinical outcomes.

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.

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.

Access to the World Health Organization-recommended essential diagnostics for invasive fungal infections in critical care and cancer patients in Africa: A diagnostic survey

BACKGROUND

Invasive fungal infections (IFIs) contribute to significant morbidity and mortality among patients with haemato-oncological conditions, seriously ill hospitalised patients and those in intensive care (ICU). We surveyed for the World Health Organization-recommended essential diagnostic tests for IFIs in these risk groups in Africa.

METHODS

The Global Action For Fungal Infections (GAFFI) evaluated the different levels of access to both diagnostics for IFIs for populations in Africa, with the aim of building a comparative dataset and a publicly available interactive map. Data was collected through a validated questionnaire administered to a country leader in relevant topics (i.e., HIV, laboratory coordination) and/or Ministry of Health representatives and followed up with 2 rounds of validation by video calls, and later confirmation by email of findings.

RESULTS

Initial data was collected from 48 African countries covering 99.65 % of the population. Conventional diagnostics such as blood cultures, direct microscopy and histopathology were often used for diagnosis of IFIs in more than half of the facilities. Bronchoscopy was rarely done or not done in 20 countries (population 649 million). In over 40 African countries (population >850 million), Aspergillus antigen testing was never performed in either the public or private sectors. Computed tomography (CT) imaging is routinely used in 27 (56 %) of countries in the public sector and 21 44 %) in the private sector. However, magnetic resonance imaging remains relatively uncommon in most African countries.

CONCLUSIONS

There are critical gaps in the availability of essential diagnostics for IFIs in Africa, particularly Aspergillus antigen testing and modern medical imaging modalities. Early diagnosis and commencement of targeted therapy of IFIs are critical for optimal outcomes from complex cancer therapies.

Invasive pulmonary aspergillosis in the ICU: tale of a broadening risk profile

PURPOSE OF REVIEW

In the absence of histopathological proof, the diagnosis of invasive pulmonary aspergillosis (IPA) is usually based on mycology (not on tissue), medical imaging, and the patient's risk profile for acquiring invasive fungal disease. Here, we review the changes in risk profile for IPA that took place over the past decades.

RECENT FINDINGS

In the early 2000s IPA was considered exclusively a disease of immunocompromised patients. Particularly in the context of critical illness, the risk profile has been broadened steadily. Acute viral infection by influenza or SARS-Cov-2 are now well recognized risk factors for IPA.

SUMMARY

The classic risk profile ('host factors') reflecting an immunocompromised status was first enlarged by a spectrum of chronic conditions such as AIDS, cirrhosis, and chronic obstructive pulmonary disease. In the presence of critical illness, especially characterized by sepsis and/or severe respiratory distress, any chronic condition could add to the risk profile. Recently, acute viral infections have been associated with IPA leading to the concepts of influenza-associated IPA and COVID-19-associated IPA. These viral infections may affect patients without underlying disease. Hence, the risk for IPA is now a reality for ICU patients, even in the absence of any chronic conditions.

Unusual Aspergillus Pleural Effusion in a Patient With Immunodeficiency

Pleural aspergillosis is a rare form of invasive bronchopulmonary aspergillosis that is most often seen in immunocompromised hosts. It appears because of the coagulative necrosis of lung tissue induced by the Aspergillus species, which promotes the formation of a fungal pleural effusion. We present the case of a 51-year-old liver transplant patient on chronic immunosuppression therapy who presented with respiratory failure and was found to have a large left-sided pleural effusion from invasive aspergillosis. After thoracentesis, he started antifungal therapy with isavuconazole. This newer, second-generation broad-spectrum triazole is non-inferior to voriconazole but with less hepatotoxicity and was noted to have an improvement in his symptoms. In the differential diagnosis of pulmonary effusions in immunocompromised patients, it is crucial to consider invasive aspergillosis, as demonstrated by our case. This case study highlights the importance of quick diagnosis and treatment to enhance outcomes in this vulnerable population.

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.

Pulmonary Aspergillosis in Critically Ill COVID-19 Patients Admitted to the Intensive Care Unit: A Retrospective Cohort Study

COVID-19-associated pulmonary aspergillosis (CAPA) is a life-threatening fungal infection that mainly affects critically ill patients. The aim of this study was to assess the incidence and clinical outcomes of putative CAPA in critically ill COVID-19 patients. This retrospective observational cohort study included 181 cases from 5 ICUs at Vienna General Hospital between January 2020 and April 2022. Patients were diagnosed with putative CAPA according to the AspICU classification, which included a positive Aspergillus culture in a bronchoalveolar lavage sample, compatible signs and symptoms, and abnormal medical imaging. The primary outcome was adjusted 60-day all-cause mortality from ICU admission in patients with vs. without putative CAPA. Secondary outcomes included time from ICU admission to CAPA diagnosis and pathogen prevalence and distribution. Putative CAPA was identified in 35 (19.3%) of 181 COVID-19 patients. The mean time to diagnosis was 9 days. Death at 60 days occurred in 18 of 35 (51.4%) patients with CAPA and in 43 of 146 (29.5%) patients without CAPA (adjusted HR (95%CI) = 2.15 (1.20–3.86, p = 0.002). The most frequently isolated Aspergillus species was Aspergillus fumigatus. The prevalence of putative pulmonary aspergillosis in critically ill COVID-19 patients was high and was associated with significantly higher mortality.

Invasive Pulmonary Aspergillosis: Not Only a Disease Affecting Immunosuppressed Patients

Fungal infections have become a common threat in Intensive Care Units (ICU). The epidemiology of invasive fungal diseases (IFD) has been extensively studied in patients severely immunosuppressed over the last 20-30 years, however, the type of patients that have been admitted to hospitals in the last decade has made the healthcare system and ICU a different setting with more vulnerable hosts. Patients admitted to an ICU tend to have older age and higher severity of disease. Moreover, the number of patients being treated in ICU are often immunosuppressed as a result of the widespread use of immunomodulatory agents, such as corticosteroids, chemotherapy, and biological agents. The development of Invasive Pulmonary aspergillosis (IPA) reflects a different clinical trajectory to affected patients. The increasing use of corticosteroids would probably explain the higher incidence of IPA especially in critically ill patients. In refractory septic shock, severe community-acquired pneumonia (SCAP), and acute respiratory distress syndrome (ARDS), the use of corticosteroids has re-emerged in order to decrease unacceptably high mortality rates associated with these clinical conditions. It is also pertinent to note that different reports have used different diagnosis criteria, and this might explain the different incidence rates. Another layer of complexity to better understand current IPA data is related to more aggressive acquisition of samples through invasive respiratory examinations.