Aspergillosis in the ICU - The new 21st century problem?

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Prognostic Scores and Azole-Resistant Aspergillus fumigatus in Invasive Aspergillosis from an Indian Respiratory Medicine ICU (ICU Patients with IA Suspicion)

Objective: To assess the effectiveness of three general prognostic models (APACHE II, SAPS II, and SOFA) with serum galactomannan antigen in a clinically suspected invasive aspergillosis (IA) subpopulation admitted to a respiratory medicine ICU and to identify azole-resistant Aspergillus fumigatus (ARAF) cases. Methodology and Results: A total of 235 clinically suspected IA patients were prospectively enrolled and observed 30-day mortality was 29.7%. The three general models showed poor discrimination assessed by area under receiver operating characteristic (ROC) curves (AUCs, <0.7) and good calibration (p = 0.92, 0.14, and 0.13 for APACHE II, SAPS II, and SOFA, respectively), evaluated using Hosmer–Lemeshow goodness-of-fit tests. However, discrimination was significantly better with galactomannan values (AUC, 0.924). In-vitro antifungal testing revealed higher minimum inhibitory concentration (MIC) for 12/34 isolates (35.3%) whereas azole resistance was noted in 40% of Aspergillus fumigatus isolates (6/15) with two hotspot cyp51A mutations, G54R and P216L. Conclusions: Patients diagnosed with putative and probable IA (71.4% and 34.6%, respectively), had high mortality. The general prognostic model APACHE II seemed fairly accurate for this subpopulation. However, the use of local GM cut-offs calculated for mortality, may help the intensivists in prompt initiation or change of therapy for better outcome of patients. In addition, the high MICs highlight the need of antifungal surveillance to know the local resistance rate which might aid in patient treatment.

COVID-19-Associated Pulmonary Aspergillosis at an Academic Medical Center in the Midwestern United States

Pulmonary aspergillosis has been reported at high rates in patients with coronavirus disease 2019 (COVID-19) and is associated with high morbidity and mortality. We retrospectively assessed all patients admitted to an intensive care unit during the early COVID-19 surge (3/17/20-5/10/20) at our medical center in the midwestern USA for the presence of COVID-19-associated pulmonary aspergillosis (CAPA). Patients were not routinely screened for CAPA; diagnostic work-up for fungal infections was pursued when clinically indicated. Among 256 patients admitted to the ICU with severe COVID-19, 188 (73%) were intubated and 62 (24%) ultimately expired within 30 days of admission to the ICU. Only three patients (1%) were found to have CAPA; diagnosis was made by tracheal aspirate cultures in two cases and by bronchoalveolar lavage fluid Aspergillus galactomannan in one case. None of the patients who developed CAPA had classic risk factors for invasive fungal infection. The occurrence of CAPA was much lower than that reported at other centers, likely reflecting the local epidemiology.

Pulmonary aspergillosis in critically ill patients with Coronavirus Disease 2019 (COVID-19)

Occurrence of putative invasive pulmonary aspergillosis was screened in 153 consecutive adult intensive care unit (ICU) patients with respiratory samples addressed for mycological diagnosis during a 6-week period at the emergence of coronavirus disease 2019 (COVID-19) pandemic. Positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) was observed for 106 patients (69.3%). Nineteen of them (17.9%) with positive Aspergillus results were considered as having putative invasive pulmonary aspergillosis. These observations underline the risk of pulmonary aspergillosis in COVID-19 patients, even in patients not previously known to be immunosuppressed, advocating active search for Aspergillus infection and prompt antifungal treatment. Standardized surveillance protocols and updated definitions for ICU putative invasive pulmonary aspergillosis are needed.

Lay Abstract

Adult ICU patients with respiratory samples addressed for mycological diagnosis were screened during the emergence of COVID-19 pandemic. Positive SARS-CoV-2 PCR was observed for 106 patients, nineteen of them (17.9%) having aspergillosis. This underlines the risk of aspergillosis in COVID-19 patients.

Does galactomannan testing increase diagnostic accuracy for IPA in the ICU? A prospective observational study

Background

An algorithm for distinguishing invasive pulmonary aspergillosis (IPA) in critically ill patients (AspICU) has been proposed but not tested.

Methods

This was a prospective observational study applying the AspICU protocol to patients with positive Aspergillus culture (PAC group) and those with negative aspergillus culture but positive galactomannan test in respiratory tract samples (only positive galactomannan (OPG group)). Patients underwent a standardized diagnostic workup with bronchoscopy, computed tomography (CT), and galactomannan determination in serum and bronchoalveolar lavage fluid (BALF).

Results

We included 85 patients in the study. Of these, 43 had positive aspergillus cultures and 42 patients had only a positive galactomannan test. There were no statistically significant differences in baseline characteristics, underlying conditions or ICU scores between the two groups. The galactomannan titre in BALF was significantly higher in the positive aspergillus culture (PAC) group (enzyme immunoassay (EIA) 5.9, IQR 3.2–5.7) than in the OPG group (EIA 1.7, IQR 0.9–4.5) (p < 0.001). Classic features of IPA were detected on CT in 37.5 % and 36.6 % of patients in the PAC and OPG groups, respectively. There were no statistically significant differences between the PAC and the OPG group in relation to AspICU or European Organization for the Research and Treatment of Cancer (EORTC) criteria. A positive aspergillus culture was a stronger trigger for initiating antimycotic treatment than positive BALF galactomannan: 88.4 % of patients in the PAC group were regarded by clinicians as having IPA and received antimycotic treatment as opposed to 59.5 % in the OPG group (p = 0.002). The 180-day mortality was 58.1 % in the PAC group and 59.5 % in the OPG group.

Conclusions

The inclusion of BALF galactomannan as an additional entry criterion for the AspICU clinical algorithm could increase the diagnostic sensitivity for IPA in ICU patients.

Trial registration

The study was registered at ClinicalTrials.gov (registration number NCT01866020) on 27 May 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1326-1) contains supplementary material, which is available to authorized users.

Protein targets for broad-spectrum mycosis vaccines: quantitative proteomic analysis of Aspergillus and Coccidioides and comparisons with other fungal pathogens

Aspergillus species are responsible for most cases of fatal mold infections in immunocompromised patients, particularly in those receiving hematopoietic stem cell transplants. Experimental vaccines in mouse models have demonstrated a promising avenue of approach for the prevention of aspergillosis, as well as infections caused by other fungal pathogens, such as Coccidioides, the etiological agent of valley fever (coccidioidomycosis). Here, we investigated the hyphal proteomes of Aspergillus fumigatus and Coccidioides posadasii via quantitative MS(E) mass spectrometry with the objective of developing a vaccine that cross-protects against these and other species of fungi. Several homologous proteins with highly conserved sequences were identified and quantified in A. fumigatus and C. posadasii. Many abundant proteins from the cell wall of A. fumigatus present themselves as possible cross-protective vaccine candidates, due to the high degree of sequence homology to other medically relevant fungal proteins and low homologies to human or murine proteins.

Management of invasive aspergillosis in patients with COPD: rational use of voriconazole

Invasive pulmonary aspergillosis (IPA) is an important cause of mortality in patients with hematologic malignancies. The reported incidence of IPA in the context of chronic obstructive pulmonary disease (COPD) seems to increase. Approximately 1%-2% of overall fatal cases of IPA occur in COPD patients. The combination of factors such as lung immune imbalance, long-term corticosteroid use, increasing rate of bacterial exacerbations over time, and malnutrition are responsible for the emergence of IPA in these patients. The diagnosis of IPA is difficult to establish, which explains the delay in implementing accurate antifungal therapy and the high mortality rate. Persistent pneumonia nonresponsive to appropriate antibiotic treatment raises the concern of an invasive fungal infection. Definite diagnosis is obtained from tissue biopsy evidencing Aspergillus spp. on microscopic examination or in culture. Culture and microscopy of respiratory tract samples have a sensitivity and specificity of around 50%. Other diagnostic tools can be useful in documenting IPA: computed tomography (CT) scan, nonculture-based tests in serum and/or in bronchoalveolar lavage such as antibody/antigen tests for Aspergillus spp. More recent tools such as polymerase chain reaction or [1-->3]-beta-D-glucan have predictive values that need to be further investigated in COPD patients. Antifungal monotherapy using azole voriconazole is recommended as a first-line treatment of IPA. This review assesses the use of voriconazole in COPD patients.

NAC is associated with additional alleviation of lung injury induced by invasive pulmonary aspergillosis in a neutropenic model

AIM

Neutropenic individuals are at high risk for invasive pulmonary aspergillosis (IPA), a life-threatening infection. To evaluate the therapeutic potential of antioxidants, IPA was induced in neutropenic mice and the effect of N-acetyl-l-cysteine (NAC) on oxidative stress levels and lung injury was analyzed.

METHODS

Mice were pretreated with three daily intraperitoneal injections of 150 mg/kg cyclophosphamide, followed by intratracheal inoculation with 4.5x10(6) conidia of Aspergillus fumigatus. The infected mice were then randomly assigned to an amphotericin B (AMB) group, an AMB plus NAC group, or an untreated control (C) group. In each group, the duration of treatment was 24, 48, or 72 h, and activities such as appearance, feeding, and dermal temperature were observed throughout the experiment. Sera and lung tissues were collected and analyzed by quantitative enzyme-linked immunosorbent assay (ELISA) for total protein, superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-alpha), and interleukin-10 (IL-10) levels. The wet/dry weight ratio of the lung was also calculated and lung sections were stained with hematoxylin-eosin for pathological examination and with methenamine silver stain for fungus detection.

RESULTS

Compared with the mice untreated with NAC, mice in the AMB plus NAC group had increased SOD and reduced MDA levels both systemically and locally at 24, 48, and 72 h after inoculation with conidia. NAC treatment also decreased the pulmonary protein content at 48 and 72 h and the lung wet/dry weight ratio at 24 and 48 h. Additionally, NAC enhanced pulmonary production of TNF-alpha and IL-10 at 24 h and 48 h.

CONCLUSION

In combination with antifungal therapy, NAC treatment can alleviate oxidative stress and lung injury associated with IPA in neutropenic mice.Acta Pharmacologica Sinica (2009) 30: 980-986; doi: 10.1038/aps.2009.83.

Management of invasive pulmonary aspergillosis in non-neutropenic critically ill patients

During recent years, a rising incidence of invasive pulmonary aspergillosis (IPA) in non-neutropenic critically ill patients has been reported. Critically ill patients are prone to develop disturbances in immunoregulation during their stay in the ICU, which render them more vulnerable for fungal infections. Risk factors such as chronic obstructive pulmonary disease (COPD), prolonged use of steroids, advanced liver disease, chronic renal replacement therapy, near-drowning and diabetes mellitus have been described. Diagnosis of IPA may be difficult and obtaining histo- or cytopathological demonstration of the fungus in order to meet the gold standard for IPA is not always feasible in these patients. Laboratory markers used as a non-invasive diagnostic tool, such as the galactomannan antigen test (GM), 1,3-beta-glucan, and Aspergillus PCR, show varying results. Antifungal therapy might be considered in patients with persistent pulmonary infection who exhibit risk factors together with positive cultures or sequentially positive GM and Aspergillus PCR in serum, in whom voriconazole is the drug of choice. The benefit of combination antifungal therapy lacks sufficient evidence so far, but this treatment might be considered in patients with breakthrough infections or refractory disease.

Estado actual del diagnóstico precoz de las infecciones invasoras causadas por Aspergillus y otros hongos filamentosos emergentes

The usefulness of surrogate markers in the diagnosis of invasive fungal infections caused by Aspergillus and other emerging mycelial fungi is based on the ability of surrogate markers to detect the infection caused by different species of mycelial fungi. Conventional microbiological methods for diagnosis of fungal disease are slow and insensitive. Antigen based assays or measurement of (1-3)-beta-D-glucan in blood have been developed and validated in clinical laboratories. We review these diagnostic contemporary tools, their clinical application and impact.