Invasive Respiratory Fungal Infections in COVID-19 Critically Ill Patients

Development of a murine model to study the cerebral pathogenesis of Aspergillus fumigatus

IMPORTANCE

Molds are environmental fungi that can cause disease in immunocompromised individuals. The most common pathogenic mold is Aspergillus fumigatus, which is typically inhaled into the lungs and causes invasive pulmonary disease. In a subset of these patients, this infection can spread from the lungs to other organs including the brain, resulting in cerebral aspergillosis. How A. fumigatus causes brain disease is not well understood and these infections are associated with extremely high mortality rates. Thus, we developed an animal model to study the pathogenesis of cerebral aspergillosis to better understand this disease and develop better treatments for these life-threatening infections.

Post-COVID pulmonary fungal infections: An unanticipated predicament or a ticking time bomb? Clinico-microbiological profile of cases encountered during the second wave of COVID-19 pandemic at a teaching hospital in the Himalayas with a brief literature review

Introduction

This study attempts to generate preliminary data regarding post-COVID pulmonary fungal infections, namely, COVID-19-associated pulmonary aspergillosis (CAPA), COVID-19-associated pulmonary mucormycosis (CAPM), and mixed infections from the Himalayas and compares the micro-radio-clinical profile and outcomes of the affected patients.

Materials and Methods

A retrospective data analysis was conducted, where clinical profiles, microbiological and radiological reports, and outcomes of n = 16 patients of post-COVID pulmonary infections were compared.

Results

Of n = 16 patients, n = 7 had CAPA (n = 5 Aspergillus fumigatus, n = 1 Aspergillus flavus, and n = 1 Aspergillus niger), n = 5 CAPM (Rhizopus arrhizus), and n = 4 with mixed infections (n = 3 infected with Aspergillus fumigatus and Rhizopus spp. and n = 1 with Aspergillus flavus and Rhizopus arrhizus). Thick-walled cavitary lesions, air-fluid levels, and multiple centrilobular nodules were some of the common radiological findings reported among these patients.

Conclusion

The immuno-compromised state following COVID-19 infection and treatment might be responsible for the progression of regular exposure to the dense Himalayan vegetation into an invasive pulmonary fungal infection. Suspecting post-COVID pulmonary fungal infection is necessary for primary care physicians to ensure timely referral to higher centers. Mixed pulmonary fungal infections (coinfection with Aspergillus spp. and Rhizopus spp.) are also emerging as important sequelae of COVID-19.

The effect of COVID-19 on the frequency of Pneumocystis jirovecii pneumonia: a monocentric, retrospective, and observational study

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) and SARS-CoV2 share some similarities in their effects on the respiratory system, clinical presentation, and management. The COVID-19 pandemic required rapid action to curb transmission and mitigate its lethiferous impact. Non-pharmaceutical interventions (NPIs) were globally adopted. We hypothesized that these measures reduced the transmission and acquisition of P. jirovecii in both hospital and community settings.

METHODS

We conducted a retrospective observational study on 2950 respiratory specimens from patients with suspected pulmonary infection, analyzed at the Laboratory of Parasitology Unit of the Policlinico Tor Vergata of Rome, Italy, from January 2014 to December 2022.

RESULTS

We show a significant reduction in the frequency of PCP in the COVID-19 pandemic era compared to the previous period. Among the four sequence types of P. jirovecii identified, genotype 1 was the most prevalent (37%). We observed a non-significant trend of decreasing cases with genotype 1 and increasing cases with genotype 3 over the study period.

CONCLUSIONS

The nationwide implementation of NPIs against COVID-19 may have changed the microbiological landscape of exposure, thereby decreasing the exposure to P. jirovecii and consequently reducing the incidence of PCP.

Use of Venovenous Extracorporeal Membrane Oxygenation in Patients With Acute Respiratory Distress Syndrome Caused by Fungal Pneumonia

Background: Patients with fungal pneumonias sometimes progress to acute respiratory distress syndrome (ARDS). Mortality has been reported as high as 60% to 90% in this group. Venovenous extracorporeal membrane oxygenation (VV-ECMO) can be used to support such patients, however, outcomes are not well understood. Patients and Methods: This was a retrospective study across the four adult ECMO centers in Minnesota for one decade (2012-2022). The outcomes of interest were duration of ECMO, survival rate, and complications. Data were extracted from the electronic medical record and analyzed using descriptive statistics. Results: Fungal pneumonia was the etiology of ARDS in 22 of 422 (5%) adults supported with VV-ECMO during the 10-year study period. Median patient age was 43 years (interquartile range [IQR], 35-56) and 68% were male. By type of fungal infection, 16 (72%) had blastomycosis, five (22%) had pneumocystis, and one (5%) had cryptococcus. Of the 16 patients with blastomycosis two were immunosuppressed whereas all five of the pneumocystis patients were immunosuppressed. The overall survival rate was 73%; most patients with blastomycosis (67%) and pneumocystis (80%) survived to hospital discharge. The duration of ECMO support was greater for the pneumocystis group (median, 30 days; IQR, 21-43) compared with blastomycosis (median, 10 days; IQR, 8-18). Conclusions: Our findings support the use of VV-ECMO for ARDS caused by fungal pneumonias in select immunocompetent and immunocompromised patients. Although survival was high, patients with pneumocystis required longer ECMO runs.

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.

Perturbations of immune landscape in COVID-19 associated mucormycosis

BACKGROUND

A rise in secondary fungal infections during the COVID-19 pandemic necessitates a deeper understanding of the associated immunological perturbations.

OBJECTIVES

To evaluate the clinical and immunological characteristics observed in patients with COVID-19 associated mucormycosis (CAM) infection.

PATIENTS/ METHODS

Cases of mucormycosis with or post-COVID-19 infection were compared with cases of acute COVID-19 and convalescent COVID-19. Lymphocyte subsets, cytokines and other laboratory markers were compared between the groups.

RESULTS

The frequency of proposed risk factors for CAM was diabetes mellitus (77%), recent history of steroid use (69%) and hypoxia during COVID-19 infection (52%). Iron metabolism was dysregulated in CAM patients with low TIBC and total iron. Further, CAM was accompanied with lymphopenia with drastic reduction in B cell counts; however, plasmablasts were not altered. Further, CAM patients had low immunoglobulin levels and antibodies specific to mucor peptide did not increase in CAM suggesting dysfunction in B-cell response. There was increase in activated effector cytotoxic CD8 T cells and NK cells in CAM compared with COVID-19 infection and healthy controls. Among T helper cells, Tregs were reduced and Th-1 frequency was increased in CAM compared with COVID-19 infection. A distinct cytokine signature was evident in CAM with increase in IL-1β, IFN-γ, IL-6, IL-22, IL-17A, IL-10, IL-2, IL-8, IL-7, IL-21 and GM-CSF.

CONCLUSION

This is the first study on immunophenotyping in CAM suggesting the need for long-term monitoring of B-cell function after SARS-CoV-2 in patients with dysregulated glycaemic control and the possible benefit of therapeutic supplementation with intravenous immunoglobulins in CAM.

Antifungal Activity of Isavuconazole and Comparator Agents against Contemporaneous Mucorales Isolates from USA, Europe, and Asia-Pacific

Isavuconazole is the only US FDA-approved antifungal for treating invasive mucormycosis. We evaluated isavuconazole activity against a global collection of Mucorales isolates. Fifty-two isolates were collected during 2017-2020 from hospitals located in the USA, Europe, and the Asia-Pacific. Isolates were identified by MALDI-TOF MS and/or DNA sequencing and susceptibility tested by the broth microdilution method following CLSI guidelines. Isavuconazole (MIC_50/90, 2/>8 mg/L) inhibited 59.6% and 71.2% of all Mucorales isolates at ≤2 mg/L and ≤4 mg/L, respectively. Among comparators, amphotericin B (MIC_50/90, 0.5/1 mg/L) displayed the highest activity, followed by posaconazole (MIC_50/90, 0.5/8 mg/L). Voriconazole (MIC_50/90, >8/>8 mg/L) and the echinocandins (MIC_50/90, >4/>4 mg/L) had limited activity against Mucorales isolates. Isavuconazole activity varied by species and this agent inhibited at ≤4 mg/L 85.2%, 72.7%, and 25% of Rhizopus spp. (n = 27; MIC_50/90, 1/>8 mg/L), Lichtheimia spp. (n = 11; MIC_50/90, 4/8 mg/L), and Mucor spp. (n = 8; MIC₅₀, >8 mg/L) isolates, respectively. Posaconazole MIC_50/90 values against Rhizopus, Lichtheimia, and Mucor species were 0.5/8 mg/L, 0.5/1 mg/L, and 2/- mg/L, respectively; amphotericin B MIC_50/90 values were 1/1 mg/L, 0.5/1 mg/L, and 0.5/- mg/L, respectively. As susceptibility profiles varied among Mucorales genera, species identification and antifungal susceptibility testing are advised whenever possible to manage and monitor mucormycosis.

Concurrent COVID-19 and pneumocystis carinii pneumonia in a patient subsequently found to have underlying hairy cell leukemia

SARS-CoV-2 infection manifestation has great diversity and it becomes even greater while co-infection occurs or there is a serious underlying disease in an affected patient. In this case report, we present a case of a 71-year-old man who underwent a chest CT scan following the development of fever, weakness, and pulmonary symptoms. Chest CT scan showed segmental consolidation with centrilobular nodular infiltration, ground glass opacifications in the inferior segment of the left upper and lower lobes, and left lung pleural thickening which was atypical for either COVID-19 infection or pneumocystis carinii pneumonia but his SARS-CoV-2 PCR result was positive and he received COVID-19 treatment. His symptoms recurred after a few months with the same chest CT findings and subsequent bronchoalveolar lavage revealed the presence of pneumocystis carinii infection. Consequently, he received cotrimoxazole which caused improvement in symptoms, nonetheless splenomegaly and anemia remained in his clinical and laboratory investigation. Accordingly, bone marrow study and flow cytometry was done and confirmed the previously undiagnosed hairy cell leukemia. This case accentuates the fact that when we face atypical clinical or paraclinical features in a COVID-19 patient, we should explore for coinfection or unknown underlying diseases.