Characteristics of lower respiratory tract microbiota in the patients with post-hematopoietic stem cell transplantation pneumonia.

Background: Pneumonia is a leading cause of non-relapse mortality after hematopoietic stem cell transplantation (HSCT), and the lower respiratory tract (LRT) microbiome has been proven to be associated with various respiratory diseases. However, little is known about the characteristics of the LRT microbiome in patients with post-HSCT compared to healthy controls (HC) and community-acquired pneumonia (CAP). Methods: Bronchoalveolar lavage samples from 55 patients with post-HSCT pneumonia, 44 patients with CAP, and 30 healthy volunteers were used to detect microbiota using 16S rRNA gene sequencing. Results: The diversity of the LRT microbiome significantly decreased in patients with post-HSCT pneumonia, and the overall community was different from the CAP and HC groups. At the phylum level, post-HSCT pneumonia samples had a high abundance of Actinobacteria and a relatively low abundance of Bacteroidetes. The same is true for non-survivors compared with survivors in patients with post-HSCT pneumonia. At the genus level, the abundances of Pseudomonas, Acinetobacter, Burkholderia, and Mycobacterium were prominent in the pneumonia group after HSCT. On the other hand, gut-associated bacteria, Enterococcus were more abundant in the non-survivors. Some pathways concerning amino acid and lipid metabolism were predicted to be altered in patients with post-HSCT pneumonia. Conclusions: Our results reveal that the LRT microbiome in patients with post-HSCT pneumonia differs from CAP patients and healthy controls, which could be associated with the outcome. The LRT microbiota could be a target for intervention during post-HSCT pneumonia.

Clinical Manifestations of Pulmonary Mucormycosis in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: A 21-Case Series Report and Literature Review.

Introduction: Mucormycosis is a rare, invasive disease caused by opportunistic pathogens related to the Mucorales order with high fatality rates in immunocompromised hosts, especially in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Diagnosis and treatment of pulmonary mucormycosis in recipients of allo-HSCT remains challenging. Purpose: The aim of this study is to summarize and analyze the clinical features of pulmonary mucormycosis in recipients of allo-HSCT to explore further clinical research directions for this rare fungal infection in the particular populations. Methods: We retrospectively reviewed pulmonary mucormycosis in patients who received allo-HSCT in our hospital from January 2010 to December 2020. A total of 21 patients fulfilled the diagnostic criteria for pulmonary mucormycosis according to the European Organization for Research and Treatment of Cancer and Mycoses Study Group (EORTC/MSG) criteria. Demographic and clinical data, mycological and histopathological records, and treatment and prognosis data were collected. Clinical variables were compared between survivors and nonsurvivors. The survival days of patients with and without graft-versus-host disease (GVHD) and hemoptysis were compared separately. Results: Most of the recipients of allo-HSCT were male patients with a mean age of 43 years. Acute myeloid leukemia (AML) was the most common primary hematologic malignancy. Extrapulmonary involvement accounted for 28.6%, of the cases, including central nervous system (n = 5) and skin and soft tissue (n = 1). The median time to infection was 96 days after allo-HSCT. Clinical presentations were nonspecific, including fever (76.2%) and cough (85.7%), as well as dyspnea (19.0%), chest pain (38.1%), and hemoptysis (61.9%). Ground-glass infiltrates (95.0%) and nodules/masses (80%) were the most common radiographic patterns on chest CT. The most common pathogen was Rhizopus (63.2%), and breakthrough infection accounted for 90.5%. Fifteen of the patients died within one year, and the median time from diagnosis to death was 47 days. Conclusion: Mucormycosis is a fatal infection disease. Opportunistic infections in recipients of allo-HSCT are mainly breakthrough infections and may have a seasonal distribution (summer and autumn) and more cases of death in autumn. The marked reversed halo sign can be seen both in the initial stage of infection and after antifungal treatment. In our case series, patients with pulmonary mucormycosis with extrapulmonary involvement 100% died within one year. There are more patients with GVHD before infection and hemoptysis in nonsurvivors than survivors within 100 days. Patients with GVHD before infection and hemoptysis have a shorter survival time than those without.

[The clinical-radiologic-pathologic features of imported pulmonary histoplasmosis].

OBJECTIVE: To describe the clinical features and treatment of imported pulmonary histoplasmosis and therefore to improve the recognition and differential diagnosis of this disease. METHODS: The clinical data of 3 patients with imported pulmonary histoplasmosis in our hospital were collected and analyzed. Literatures published since 1989 were retrieved with 'pulmonary histoplasmosis' from PubMed, China National Knowledge Infrastructure (CNKI), Wanfang Data and VIP data, of which all the literatures about imported pulmonary histoplasmosis were reviewed. The clinical manifestations, diagnostic methods and treatment were summarized. RESULTS: All the 3 cases of imported pulmonary histoplasmosis were immunocompetent hosts, all were males, age were from 44-67 years, and had a history of exploring the cave or tunnel inhabited by bats in the epidemic areas. All of them developed influenza-like symptoms varying in severity after the onset of the disease. Pulmonary multiple nodules and mediastinal lymphadenopathy were found on chest images. One patient underwent percutaneous lung biopsy and the other two received video-assisted thoracoscopic lung biopsy. All the 3 patients showed consistent histopathological findings, such as granulomatous inflammation with necrosis. Pathogen culture with lung biopsy in the first case was identified as histoplasma. All the 3 cases were treated with itraconazole, and recovered with good prognosis. Thirteen literatures in English were obtained, which reported 60 cases with imported pulmonary histoplasmosis. Forty-two of them were males, 16 were females and 2 undefined. The range of their age was from 17-64 years. No imported pulmonary histoplasmosis was reported so far in Chinese literature. Common features of imported pulmonary histoplasmosis were consistent with our patients, including epidemiology, influenza-like symptoms and bilateral pulmonary nodules, recovery with or without antifungal therapy. CONCLUSION: The epidemiologic history, influenza-like symptoms and bilateral pulmonary nodules provide valuable diagnostic clues for imported histoplasmosis. Clinical features with pathologic findings and good response to antifungal therapy could make the diagnosis even without pathogen detection if other etiology is unlikely.