Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
1.
BMC Emerg Med ; 23(1): 28, 2023 03 14.
Article in English | MEDLINE | ID: covidwho-2285110

ABSTRACT

INTRODUCTION: Bacterial infections are frequently seen in the emergency department (ED), but can be difficult to distinguish from viral infections and some non-infectious diseases. Common biomarkers such as c-reactive protein (CRP) and white blood cell (WBC) counts fail to aid in the differential diagnosis. Neutrophil CD64 (nCD64), an IgG receptor, is suggested to be more specific for bacterial infections. This study investigated if nCD64 can distinguish bacterial infections from other infectious and non-infectious diseases in the ED. METHODS: All COVID-19 suspected patients who visited the ED and for which a definitive diagnosis was made, were included. Blood was analyzed using an automated flow cytometer within 2 h after presentation. Patients were divided into a bacterial, viral, and non-infectious disease group. We determined the diagnostic value of nCD64 and compared this to those of CRP and WBC counts. RESULTS: Of the 291 patients presented at the ED, 182 patients were included with a definitive diagnosis (bacterial infection n = 78; viral infection n = 64; non-infectious disease n = 40). ROC-curves were plotted, with AUCs of 0.71 [95%CI: 0.64-0.79], 0.77 [0.69-0.84] and 0.64 [0.55-0.73] for nCD64, WBC counts and CRP, respectively. In the bacterial group, nCD64 MFI was significantly higher compared to the other groups (p < 0.01). A cut-off of 9.4 AU MFI for nCD64 corresponded with a positive predictive value of 1.00 (sensitivity of 0.27, a specificity of 1.00, and an NPV of 0.64). Furthermore, a diagnostic algorithm was constructed which can serve as an example of what a future biomarker prediction model could look like. CONCLUSION: For patients in the ED presenting with a suspected infection, nCD64 measured with automatic flow cytometry, has a high specificity and positive predictive value for diagnosing a bacterial infection. However, a low nCD64 cannot rule out a bacterial infection. For future purposes, nCD64 should be combined with additional tests to form an algorithm that adequately diagnoses infectious diseases.


Subject(s)
Bacterial Infections , COVID-19 , Noncommunicable Diseases , Humans , Neutrophils , Point-of-Care Systems , COVID-19/diagnosis , Biomarkers , Bacterial Infections/diagnosis , Bacterial Infections/metabolism , C-Reactive Protein/analysis , Emergency Service, Hospital , Diagnostic Tests, Routine , COVID-19 Testing
2.
PLoS One ; 17(1): e0262342, 2022.
Article in English | MEDLINE | ID: covidwho-1622361

ABSTRACT

PURPOSE: Coronavirus disease-2019 (COVID-19) is associated with a wide spectrum of clinical symptoms including acute respiratory failure. Biomarkers that can predict outcomes in patients with COVID-19 can assist with patient management. The aim of this study is to evaluate whether procalcitonin (PCT) can predict clinical outcome and bacterial superinfection in patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). METHODS: Adult patients diagnosed with SARS-CoV-2 by nasopharyngeal PCR who were admitted to a tertiary care center in Boston, MA with SARS-CoV-2 infection between March 17 and April 30, 2020 with a baseline PCT value were studied. Patients who were presumed positive for SARS-CoV-2, who lacked PCT levels, or who had a positive urinalysis with negative cultures were excluded. Demographics, clinical and laboratory data were extracted from the electronic medical records. RESULTS: 324 patient charts were reviewed and grouped by clinical and microbiologic outcomes by day 28. Baseline PCT levels were significantly higher for patients who were treated for true bacteremia (p = 0.0005) and bacterial pneumonia (p = 0.00077) compared with the non-bacterial infection group. Baseline PCT positively correlated with the NIAID ordinal scale and survival over time. When compared to other inflammatory biomarkers, PCT showed superiority in predicting bacteremia. CONCLUSIONS: Baseline PCT levels are associated with outcome and bacterial superinfection in patients hospitalized with SARS-CoV-2.


Subject(s)
Bacterial Infections/metabolism , COVID-19/metabolism , Procalcitonin/metabolism , Aged , Aged, 80 and over , Biomarkers/metabolism , Boston , Case-Control Studies , Female , Humans , Inflammation/metabolism , Male , Middle Aged , Retrospective Studies , SARS-CoV-2/pathogenicity
3.
J Mol Biol ; 434(4): 167409, 2022 Feb 28.
Article in English | MEDLINE | ID: covidwho-1587212

ABSTRACT

The discovery of pyroptosis and its subsequent implications in infection and immunity has uncovered a new angle of host-defence against pathogen assault. At its most simple, gasdermin-mediated pyroptosis in bacterial infection would be expected to remove pathogens from the relative safety of the cytosol or pathogen containing vacuole/phagosome whilst inducing a rapid and effective immune response. Differences in gasdermin-mediated pyroptosis between cell types, stimulation conditions, pathogen and even animal species, however, make things more complex. The excessive inflammation associated with the pathogen-induced gasdermin-mediated pyroptosis contributes to a downward spiral in sepsis. With no currently approved effective treatment options for sepsis understanding how gasdermin-mediated pyroptotic pathways are regulated provides an opportunity to identify novel therapeutic candidates against this complex disease. In this review we cover recent advances in the field of gasdermin-mediated pyroptosis with a focus on bacterial infection and sepsis models in the context of humans and other animal species. Importantly we also consider why there is considerable redundancy set into these ancient immune pathways.


Subject(s)
Bacterial Infections , Phosphate-Binding Proteins , Pore Forming Cytotoxic Proteins , Pyroptosis , Sepsis , Animals , Bacterial Infections/metabolism , Bacterial Infections/pathology , Humans , Inflammasomes , Phosphate-Binding Proteins/metabolism , Pore Forming Cytotoxic Proteins/metabolism , Sepsis/metabolism , Sepsis/pathology
4.
JCI Insight ; 7(1)2022 01 11.
Article in English | MEDLINE | ID: covidwho-1523122

ABSTRACT

Neutrophils are recognized as important circulating effector cells in the pathophysiology of severe coronavirus disease 2019 (COVID-19). However, their role within the inflamed lungs is incompletely understood. Here, we collected bronchoalveolar lavage (BAL) fluids and parallel blood samples of critically ill COVID-19 patients requiring invasive mechanical ventilation and compared BAL fluid parameters with those of mechanically ventilated patients with influenza, as a non-COVID-19 viral pneumonia cohort. Compared with those of patients with influenza, BAL fluids of patients with COVID-19 contained increased numbers of hyperactivated degranulating neutrophils and elevated concentrations of the cytokines IL-1ß, IL-1RA, IL-17A, TNF-α, and G-CSF; the chemokines CCL7, CXCL1, CXCL8, CXCL11, and CXCL12α; and the protease inhibitors elafin, secretory leukocyte protease inhibitor, and tissue inhibitor of metalloproteinases 1. In contrast, α-1 antitrypsin levels and net proteolytic activity were comparable in COVID-19 and influenza BAL fluids. During antibiotic treatment for bacterial coinfections, increased BAL fluid levels of several activating and chemotactic factors for monocytes, lymphocytes, and NK cells were detected in patients with COVID-19 whereas concentrations tended to decrease in patients with influenza, highlighting the persistent immunological response to coinfections in COVID-19. Finally, the high proteolytic activity in COVID-19 lungs suggests considering protease inhibitors as a treatment option.


Subject(s)
Bacterial Infections , Bronchoalveolar Lavage Fluid , COVID-19 , Coinfection , Influenza, Human , Adult , Aged , Bacterial Infections/complications , Bacterial Infections/immunology , Bacterial Infections/metabolism , Bacterial Infections/pathology , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/cytology , Bronchoalveolar Lavage Fluid/immunology , COVID-19/complications , COVID-19/diagnosis , COVID-19/immunology , COVID-19/pathology , Coinfection/immunology , Coinfection/metabolism , Coinfection/pathology , Cytokines/analysis , Female , Humans , Inflammation , Influenza, Human/complications , Influenza, Human/diagnosis , Influenza, Human/immunology , Influenza, Human/pathology , Lung/immunology , Lung/metabolism , Lung/pathology , Male , Middle Aged
5.
Toxins (Basel) ; 12(4)2020 04 02.
Article in English | MEDLINE | ID: covidwho-1453289

ABSTRACT

Bacterial toxins play a key role in the pathogenesis of lung disease. Based on their structural and functional properties, they employ various strategies to modulate lung barrier function and to impair host defense in order to promote infection. Although in general, these toxins target common cellular signaling pathways and host compartments, toxin- and cell-specific effects have also been reported. Toxins can affect resident pulmonary cells involved in alveolar fluid clearance (AFC) and barrier function through impairing vectorial Na+ transport and through cytoskeletal collapse, as such, destroying cell-cell adhesions. The resulting loss of alveolar-capillary barrier integrity and fluid clearance capacity will induce capillary leak and foster edema formation, which will in turn impair gas exchange and endanger the survival of the host. Toxins modulate or neutralize protective host cell mechanisms of both the innate and adaptive immunity response during chronic infection. In particular, toxins can either recruit or kill central players of the lung's innate immune responses to pathogenic attacks, i.e., alveolar macrophages (AMs) and neutrophils. Pulmonary disorders resulting from these toxin actions include, e.g., acute lung injury (ALI), the acute respiratory syndrome (ARDS), and severe pneumonia. When acute infection converts to persistence, i.e., colonization and chronic infection, lung diseases, such as bronchitis, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) can arise. The aim of this review is to discuss the impact of bacterial toxins in the lungs and the resulting outcomes for pathogenesis, their roles in promoting bacterial dissemination, and bacterial survival in disease progression.


Subject(s)
Bacteria/pathogenicity , Bacterial Infections/microbiology , Bacterial Toxins/metabolism , Lung/microbiology , Respiratory Tract Infections/microbiology , Adaptive Immunity , Animals , Bacteria/immunology , Bacteria/metabolism , Bacterial Infections/immunology , Bacterial Infections/metabolism , Bacterial Infections/pathology , Disease Progression , Host-Pathogen Interactions , Humans , Immunity, Innate , Lung/immunology , Lung/metabolism , Lung/pathology , Respiratory Tract Infections/immunology , Respiratory Tract Infections/metabolism , Respiratory Tract Infections/pathology , Signal Transduction
7.
Clin Invest Med ; 44(2): E5-18, 2021 06 14.
Article in English | MEDLINE | ID: covidwho-1278877

ABSTRACT

PURPOSE: This literature review summarizes the main immunological characteristics of type III interferons (IFN) and highlights the clinically relevant aspects and future therapeutic perspectives for these inflammatory molecules. SOURCE: Relevant articles in PubMed MEDLINE from the first publication (2003) until 2020. N=101 articles were included in this review. PRINCIPAL FINDINGS: Type III IFNs represent a relatively newly described inflammatory cytokine family. Although they induce substantially similar signalling to the well-known type I IFNs, significant functional differences make these molecules remarkable. Type III IFNs have extensive biological effects, contributing to the pathogenesis of several diseases and also offering new diagnostic and therapeutic approaches: 1) their potent anti-viral properties make them promising therapeutics against viral hepatitis and even against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is causing the current coronavirus disease 2019 (COVID-19) pandemic; 2) imbalances in the IFN-λs contribute to several forms of chronic inflammation (e.g., systemic and organ-specific autoimmune diseases) and potentially predict disease progression and therapeutic response to biologic therapies; and 3) the antitumor properties of the type III IFNs open up new therapeutic perspectives against malignant diseases. CONCLUSION: Over the last 18 years, researchers have gathered extensive information about the presence and role of these versatile inflammatory cytokines in human diseases, but further research is needed to clarify the mechanistic background of those observations. Better understanding of their biological activities will permit us to use type III IFNs more efficiently in new diagnostic approaches and individualized therapies, consequently improving patient care.


Subject(s)
COVID-19/metabolism , Cytokines/metabolism , Inflammation/metabolism , Interferons/physiology , Animals , Antiviral Agents/pharmacology , Autoimmune Diseases/metabolism , Bacterial Infections/metabolism , Disease Progression , Humans , Interferon-gamma/metabolism , Mycoses/metabolism , SARS-CoV-2 , Signal Transduction , Interferon Lambda
8.
Cells ; 10(5)2021 05 04.
Article in English | MEDLINE | ID: covidwho-1223958

ABSTRACT

Sphingolipids are important structural membrane components and, together with cholesterol, are often organized in lipid rafts, where they act as signaling molecules in many cellular functions. They play crucial roles in regulating pathobiological processes, such as cancer, inflammation, and infectious diseases. The bioactive metabolites ceramide, sphingosine-1-phosphate, and sphingosine have been shown to be involved in the pathogenesis of several microbes. In contrast to ceramide, which often promotes bacterial and viral infections (for instance, by mediating adhesion and internalization), sphingosine, which is released from ceramide by the activity of ceramidases, kills many bacterial, viral, and fungal pathogens. In particular, sphingosine is an important natural component of the defense against bacterial pathogens in the respiratory tract. Pathologically reduced sphingosine levels in cystic fibrosis airway epithelial cells are normalized by inhalation of sphingosine, and coating plastic implants with sphingosine prevents bacterial infections. Pretreatment of cells with exogenous sphingosine also prevents the viral spike protein of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) from interacting with host cell receptors and inhibits the propagation of herpes simplex virus type 1 (HSV-1) in macrophages. Recent examinations reveal that the bactericidal effect of sphingosine might be due to bacterial membrane permeabilization and the subsequent death of the bacteria.


Subject(s)
Bacterial Infections/immunology , Mycoses/immunology , Signal Transduction/immunology , Sphingosine/metabolism , Virus Diseases/immunology , Animals , Bacterial Infections/drug therapy , Bacterial Infections/metabolism , Bacterial Infections/microbiology , Cell Wall/drug effects , Ceramides/metabolism , Disease Models, Animal , Herpesvirus 1, Human/immunology , Humans , Lysophospholipids/metabolism , Membrane Microdomains/immunology , Membrane Microdomains/metabolism , Mycoses/drug therapy , Mycoses/metabolism , Mycoses/microbiology , SARS-CoV-2/immunology , Sphingolipids/metabolism , Sphingosine/analogs & derivatives , Sphingosine/pharmacology , Sphingosine/therapeutic use , Virus Diseases/drug therapy , Virus Diseases/metabolism , Virus Diseases/virology
9.
mBio ; 12(1)2021 02 16.
Article in English | MEDLINE | ID: covidwho-1088202

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is leading to public health crises worldwide. An understanding of the pathogenesis and the development of treatment strategies is of high interest. Recently, neutrophil extracellular traps (NETs) have been identified as a potential driver of severe SARS-CoV-2 infections in humans. NETs are extracellular DNA fibers released by neutrophils after contact with various stimuli and accumulate antimicrobial substances or host defense peptides. When massively released, NETs are described to contribute to immunothrombosis in acute respiratory distress syndrome and in vascular occlusions. Based on the increasing evidence that NETs contribute to severe COVID-19 cases, DNase treatment of COVID-19 patients to degrade NETs is widely discussed as a potential therapeutic strategy. Here, we discuss potential detrimental effects of NETs and their nuclease degradation, since NET fragments can boost certain bacterial coinfections and thereby increase the severity of the disease.


Subject(s)
COVID-19/metabolism , Coinfection/metabolism , Extracellular Traps/metabolism , Neutrophils/metabolism , Bacterial Infections/metabolism , Coinfection/microbiology , Coinfection/virology , Humans
10.
mBio ; 11(6)2020 11 12.
Article in English | MEDLINE | ID: covidwho-922531

ABSTRACT

Mucus plays a pivotal role in protecting the respiratory tract against microbial infections. It acts as a primary contact site to entrap microbes and facilitates their removal from the respiratory tract via the coordinated beating of motile cilia. The major components of airway mucus are heavily O-glycosylated mucin glycoproteins, divided into gel-forming mucins and transmembrane mucins. The gel-forming mucins MUC5AC and MUC5B are the primary structural components of airway mucus, and they enable efficient clearance of pathogens by mucociliary clearance. MUC5B is constitutively expressed in the healthy airway, whereas MUC5AC is upregulated in response to inflammatory challenge. MUC1, MUC4, and MUC16 are the three major transmembrane mucins of the respiratory tracts which prevent microbial invasion, can act as releasable decoy receptors, and activate intracellular signal transduction pathways. Pathogens have evolved virulence factors such as adhesins that facilitate interaction with specific mucins and mucin glycans, for example, terminal sialic acids. Mucin expression and glycosylation are dependent on the inflammatory state of the respiratory tract and are directly regulated by proinflammatory cytokines and microbial ligands. Gender and age also impact mucin glycosylation and expression through the female sex hormone estradiol and age-related downregulation of mucin production. Here, we discuss what is currently known about the role of respiratory mucins and their glycans during bacterial and viral infections of the airways and their relevance for the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Understanding the impact of microbe-mucin interaction in the respiratory tract could inspire the development of novel therapies to boost mucosal defense and combat respiratory infections.


Subject(s)
Glycoproteins/metabolism , Mucins/metabolism , Respiratory Tract Infections/microbiology , Respiratory Tract Infections/virology , Bacterial Infections/metabolism , COVID-19/virology , Glycosylation , Humans , Mucin 5AC/metabolism , Mucin-1/metabolism , Mucin-5B/metabolism , Respiratory Tract Infections/prevention & control , SARS-CoV-2/pathogenicity , Virus Diseases/metabolism
12.
Int J Mol Sci ; 21(15)2020 Jul 24.
Article in English | MEDLINE | ID: covidwho-699380

ABSTRACT

Sarcopenia in patients with liver cirrhosis (LC) has been attracting much attention these days because of the close linkage to adverse outcomes. LC can be related to secondary sarcopenia due to protein metabolic disorders and energy metabolic disorders. LC is associated with profound alterations in gut microbiota and injuries at the different levels of defensive mechanisms of the intestinal barrier. Dysbiosis refers to a state in which the diversity of gut microbiota is decreased by decreasing the bacterial species and the number of bacteria that compose the gut microbiota. The severe disturbance of intestinal barrier in LC can result in dysbiosis, several bacterial infections, LC-related complications, and sarcopenia. Here in this review, we will summarize the current knowledge of the relationship between sarcopenia and dysbiosis in patients with LC.


Subject(s)
Bacterial Infections , Dysbiosis , Gastrointestinal Microbiome , Liver Cirrhosis , Sarcopenia , Bacterial Infections/etiology , Bacterial Infections/metabolism , Bacterial Infections/microbiology , Bacterial Infections/pathology , Dysbiosis/etiology , Dysbiosis/metabolism , Dysbiosis/microbiology , Dysbiosis/pathology , Humans , Intestinal Mucosa/metabolism , Intestinal Mucosa/microbiology , Intestinal Mucosa/pathology , Liver Cirrhosis/complications , Liver Cirrhosis/metabolism , Liver Cirrhosis/microbiology , Liver Cirrhosis/pathology , Sarcopenia/etiology , Sarcopenia/metabolism , Sarcopenia/microbiology , Sarcopenia/pathology
SELECTION OF CITATIONS
SEARCH DETAIL