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Seminars in Diagnostic Pathology Nov 2017
Review
Topics: Bacteria; Bacteriological Techniques; Biopsy; Host-Pathogen Interactions; Humans; Lung; Pneumonia, Bacterial; Predictive Value of Tests; Tomography, X-Ray Computed
PubMed: 28655479
DOI: 10.1053/j.semdp.2017.06.001 -
Clinical Microbiology and Infection :... Mar 2019Rhodococcus equi is a recognized cause of disease in humans, especially in individuals who are immunocompromised. Because diphtheroids are regarded as part of normal... (Review)
Review
BACKGROUND
Rhodococcus equi is a recognized cause of disease in humans, especially in individuals who are immunocompromised. Because diphtheroids are regarded as part of normal respiratory flora, the importance of R. equi as a pulmonary pathogen may not be fully appreciated and its prevalence may be underestimated. Most treatment recommendations for R. equi infection were established before antiretroviral drugs became available for human immunodeficiency virus/AIDS therapy, and therapeutic strategies may need to be updated.
OBJECTIVES
To review the role of R. equi as a cause of pulmonary infection; to highlight its importance for clinicians and microbiologists; and to challenge current approaches to treatment, whether in immunodeficient or immunocompetent individuals.
SOURCES
A PubMed search using combinations of the following terms: 'Rhodococcus (automatically including Corynebacterium) equi' AND 'pneumonia' OR 'pulmonary' infection, then cross-checking references in the resulting cases, case series and reviews.
CONTENT
We provide a review that details the challenges in the diagnosis, microbiology and pathogenesis of pulmonary infection caused by R. equi and the options for treatment.
IMPLICATIONS
Ten to 14 days of treatment may be effective for pneumonia due to R. equi. Our review suggests that longer courses of therapy are needed for cavitary lesions and lung masses. However, recommendations for excessively prolonged treatment of all pulmonary infections arose during a time when many cases occurred in individuals with AIDS and before effective antiretroviral therapy was available. We suggest that the rationale for prolonged therapy with multiple antibiotics needs to be re-evaluated.
Topics: AIDS-Related Opportunistic Infections; Actinomycetales Infections; Anti-Bacterial Agents; Disease Management; Humans; Immunocompromised Host; Lung; Pneumonia, Bacterial; Rhodococcus equi
PubMed: 29777923
DOI: 10.1016/j.cmi.2018.04.033 -
European Respiratory Review : An... Jun 2019Idiopathic pulmonary fibrosis (IPF) arises in genetically susceptible individuals as a result of an aberrant wound-healing response following repetitive alveolar injury.... (Review)
Review
Idiopathic pulmonary fibrosis (IPF) arises in genetically susceptible individuals as a result of an aberrant wound-healing response following repetitive alveolar injury. The clinical course of the disease remains both variable and unpredictable with periods of more rapid decline, termed acute exacerbation of IPF (AE-IPF), often punctuating the disease trajectory. Exacerbations carry a significant morbidity and mortality, and their exact pathogenesis remains unclear. Given the emerging evidence that disruption and alteration in the lung microbiome plays a role in the pathogenesis and progression of IPF, this review discusses the current knowledge of the contribution of infection and the respiratory microbiome to AE-IPF.
Topics: Animals; Bacteria; Disease Progression; Dysbiosis; Host-Pathogen Interactions; Humans; Idiopathic Pulmonary Fibrosis; Lung; Microbiota; Respiratory Tract Infections
PubMed: 31285290
DOI: 10.1183/16000617.0045-2019 -
Retrovirology Jan 2021The lung is one of several organs that can be affected by HTLV-1 mediated inflammation. Pulmonary inflammation associated with HTLV-1 infection involves the... (Review)
Review
The lung is one of several organs that can be affected by HTLV-1 mediated inflammation. Pulmonary inflammation associated with HTLV-1 infection involves the interstitium, airways and alveoli, resulting in several clinical entities including interstitial pneumonias, bronchiolitis and alveolitis, depending on which structures are most affected. Augmentation of the inflammatory effects of HTLV-1 infected lymphocytes by recruitment of other inflammatory cells in a positive feedback loop is likely to underlie the pathogenesis of HTLV-1 associated pulmonary disease, as has been proposed for HTLV-1 associated myelopathy. In contrast to the conclusions of early case series, HTLV-1 associated pulmonary disease can be associated with significant parenchymal damage, which may progress to bronchiectasis where this involves the airways. Based on our current understanding of HTLV-1 associated pulmonary disease, diagnostic criteria are proposed.
Topics: Animals; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Inflammation; Lung; Lung Diseases; Mice; Paraparesis, Tropical Spastic
PubMed: 33407607
DOI: 10.1186/s12977-020-00543-z -
Expert Review of Respiratory Medicine Dec 2010Idiopathic pulmonary fibrosis (IPF) is a disease of unknown origin and progression that primarily affects older adults. Accumulating clinical and experimental evidence... (Review)
Review
Idiopathic pulmonary fibrosis (IPF) is a disease of unknown origin and progression that primarily affects older adults. Accumulating clinical and experimental evidence suggests that viral infections may play a role, either as agents that predispose the lung to fibrosis or exacerbate existing fibrosis. In particular, herpesviruses have been linked with IPF. This article summarizes the evidence for and against viral cofactors in IPF pathogenesis. In addition, we review mechanistic studies in animal models that highlight the fibrotic potential of viral infection, and explore the different mechanisms that might be responsible. We also review early evidence to suggest that the aged lung may be particularly susceptible to viral-induced fibrosis and make recommendations for future research directions.
Topics: Age Factors; Aging; Animals; Cellular Senescence; Disease Models, Animal; Gammaherpesvirinae; Herpesviridae Infections; Humans; Idiopathic Pulmonary Fibrosis; Lung; Risk Assessment; Risk Factors; Virus Diseases
PubMed: 21128751
DOI: 10.1586/ers.10.73 -
Mediators of Inflammation 2019Infection is a common cause of hospitalization and mortality in patients with systemic lupus erythematosus (SLE). How the underlying immune dysfunctions affect the...
Infection is a common cause of hospitalization and mortality in patients with systemic lupus erythematosus (SLE). How the underlying immune dysfunctions affect the antimicrobial immunity remains largely unknown. In the present study, employing the pulmonary infection model, we determined the antimicrobial defence of lupus-prone mice. After infecting with opportunistic bacterium (Hi), lupus-prone mice (B6/lpr) exhibited inefficient bacterial elimination and recovered slowly. They generated severer inflammation at the early stage of infection, as excessive accumulation of neutrophils and enhanced production of proinflammatory cytokines were observed in the lung. In addition, a large number of apoptotic cells were detected in the lungs of B6/lpr mice. For adaptive immune responses, B6/lpr mice were capable to generate enough protective Hi-specific Th17 cells. They evoked stronger Hi-specific T17 response in both lungs and spleens. Unexpectedly, both CD4 and T cells from lupus-prone mice showed deficiency in IFN- production. For humoral immune responses, compared with those of WT mice, the concentrations of Hi-specific IgA, IgM, and IgG, especially IgG, were significantly higher in the B6/lpr mice. Our findings suggest that lupus mice are capable to generate antibacterial immune responses; however, the overwhelming inflammation and overactivated immune responses increase the severity of infection.
Topics: Animals; Apoptosis; Bacteria; Cells, Cultured; Disease Models, Animal; Female; Flow Cytometry; Lung; Lupus Erythematosus, Systemic; Mice; Mice, Inbred C57BL; Opportunistic Infections; Pneumonia
PubMed: 31565032
DOI: 10.1155/2019/1701367 -
The Journal of Heart and Lung... Jun 2009Cladophialophora boppii is a dematiaceous fungus, which has been reported only rarely to be the cause of cutaneous infection. Herein we describe a C boppii parenchymal... (Review)
Review
Cladophialophora boppii is a dematiaceous fungus, which has been reported only rarely to be the cause of cutaneous infection. Herein we describe a C boppii parenchymal and bronchial infection in a lung transplant recipient. We also illustrate the clinicoradiologic patterns and review possible treatment options for these difficult infections.
Topics: Ascomycota; Emphysema; Humans; Lung; Lung Diseases, Fungal; Lung Transplantation; Male; Middle Aged; Mycoses; Pulmonary Fibrosis
PubMed: 19481026
DOI: 10.1016/j.healun.2009.02.014 -
Viruses May 2020Viruses are the most common cause of acute respiratory tract infections (ARTI). Human metapneumovirus (hMPV) frequently causes viral pneumonia which can become... (Review)
Review
Viruses are the most common cause of acute respiratory tract infections (ARTI). Human metapneumovirus (hMPV) frequently causes viral pneumonia which can become life-threatening if the virus spreads to the lungs. Even though hMPV was only isolated in 2001, this negative-stranded RNA virus has probably been circulating in the human population for many decades. Interestingly, almost all adults have serologic evidence of hMPV infection. A well-established host immune response is evoked when hMPV infection occurs. However, the virus has evolved to circumvent and even exploit the host immune response. Further, infection with hMPV induces a weak memory response, and re-infections during life are common. In this review, we provide a comprehensive overview of the different cell types involved in the immune response in order to better understand the immunopathology induced by hMPV. Such knowledge may contribute to the development of vaccines and therapeutics directed against hMPV.
Topics: Humans; Immune Evasion; Immunity, Cellular; Immunity, Innate; Lung; Metapneumovirus; Paramyxoviridae Infections; Respiratory Tract Infections; Virus Replication
PubMed: 32423043
DOI: 10.3390/v12050542 -
International Journal of Experimental... Dec 2012Melioidosis is a tropical disease caused by ingestion, percutaneous inoculation or inhalation of the Gram-negative soil saprophyte Burkholderia pseudomallei. We...
Melioidosis is a tropical disease caused by ingestion, percutaneous inoculation or inhalation of the Gram-negative soil saprophyte Burkholderia pseudomallei. We developed a reproducible experimental murine model of pneumonic melioidosis induced by inhalation of aerosolized B. pseudomallei 1026b. In a series of experiments performed to bracket the lethal dose, we found that C57BL/6 mice were modestly more resistant than BALB/c mice (median lethal dose 334 CFU/lung vs 204 CFU/lung). We further characterized infection and pulmonary inflammation in C57BL/6 mice infected with a sublethal dose. We observed pulmonary replication and dissemination of bacteria to distant organs in the first days after infection, followed by bacterial containment by day 4 and no evidence of recrudescent infection for up to 2 months. We measured a robust host inflammatory response notable for a neutrophilic bronchoalveolar lavage fluid profile, elevated cytokines and chemokines in the lung and serum and scattered foci of neutrophilic infiltrates in the alveoli and in a perivascular distribution on histological analysis. We previously noted a similar pattern of inflammation in mice infected with aerosolized B. thailandensis. This report builds on the limited literature describing experimental murine pneumonic melioidosis induced by aerosol and characterizes pulmonary infection and resultant inflammation in C57BL/6 mice infected with aerosolized B. pseudomallei. This model has utility for the study of bacterial and host factors that contribute to the virulence of melioidosis.
Topics: Aerosols; Animals; Biomarkers; Bronchoalveolar Lavage Fluid; Burkholderia pseudomallei; Cytokines; Disease Models, Animal; Inhalation Exposure; Longevity; Lung; Melioidosis; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Neutrophils; Pneumonia, Bacterial; Specific Pathogen-Free Organisms; Survival Rate
PubMed: 23136994
DOI: 10.1111/j.1365-2613.2012.00842.x -
Nature Jan 2015Lung diseases such as chronic obstructive pulmonary disease and pulmonary fibrosis involve the progressive and inexorable destruction of oxygen exchange surfaces and...
Lung diseases such as chronic obstructive pulmonary disease and pulmonary fibrosis involve the progressive and inexorable destruction of oxygen exchange surfaces and airways, and have emerged as a leading cause of death worldwide. Mitigating therapies, aside from impractical organ transplantation, remain limited and the possibility of regenerative medicine has lacked empirical support. However, it is clinically known that patients who survive sudden, massive loss of lung tissue from necrotizing pneumonia or acute respiratory distress syndrome often recover full pulmonary function within six months. Correspondingly, we recently demonstrated lung regeneration in mice following H1N1 influenza virus infection, and linked distal airway stem cells expressing Trp63 (p63) and keratin 5, called DASC(p63/Krt5), to this process. Here we show that pre-existing, intrinsically committed DASC(p63/Krt5) undergo a proliferative expansion in response to influenza-induced lung damage, and assemble into nascent alveoli at sites of interstitial lung inflammation. We also show that the selective ablation of DASC(p63/Krt5) in vivo prevents this regeneration, leading to pre-fibrotic lesions and deficient oxygen exchange. Finally, we demonstrate that single DASC(p63/Krt5)-derived pedigrees differentiate to type I and type II pneumocytes as well as bronchiolar secretory cells following transplantation to infected lung and also minimize the structural consequences of endogenous stem cell loss on this process. The ability to propagate these cells in culture while maintaining their intrinsic lineage commitment suggests their potential in stem cell-based therapies for acute and chronic lung diseases.
Topics: Animals; Bronchioles; Cell Differentiation; Cell Lineage; Cell Proliferation; Dogs; Humans; Influenza A Virus, H1N1 Subtype; Keratin-5; Lung; Madin Darby Canine Kidney Cells; Mice; Orthomyxoviridae Infections; Oxygen; Pedigree; Phosphoproteins; Pneumonia; Pulmonary Alveoli; Re-Epithelialization; Regeneration; Stem Cell Transplantation; Stem Cells; Trans-Activators
PubMed: 25383540
DOI: 10.1038/nature13903