Claus Moser

Claus Moser
Rigshospitalet | rigshospitalet · Department of Clinical Microbiology

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246
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Publications (246)
Chapter
The failing eradication of bacterial biofilm by antibiotic treatment is a major clinical challenge for patients with chronic infections. The effect of re-sensitizing infectious biofilms to antibiotics by supplemental O2 has recently been explained by the pathophysiological conditions of the infectious microenvironment. In this chapter, we argue tha...
Article
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Introduction Urinary tract infections (UTIs) with Pseudomonas aeruginosa are a severe problem in disposed patients in modern healthcare. Pseudomonas aeruginosa establishes recalcitrant biofilm infections and can develop antibiotic resistance. Gargling with avian egg yolk anti- Pseudomonas antibodies (IgY) has shown clinical effect in preventing ons...
Article
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Purpose Self-assessed poor health status is associated with increased risk of mortality in several cardiovascular conditions, but has not been investigated in patients with endocarditis. We examined health status and mortality in patients with endocarditis. Methods This is a re-specified substudy of the randomized POET endocarditis trial, which in...
Article
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Biofilm infections are tolerant to the host responses and recalcitrance to antibiotic drugs and disinfectants. The induced host-specific innate and adaptive immune responses by established biofilms are significantly implicated and contributes to the course of the infections. Essentially, the host response may be the single one factor impacting the...
Article
Background Monitoring of microbiological cause of infective endocarditis (IE) remains key in the understanding of IE; however, data from large, unselected cohorts are sparse. We aimed to examine temporal changes, patient characteristics, and in‐hospital and long‐term mortality, according to microbiological cause in patients with IE from 2010 to 201...
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Background Valve surgery guidelines for infective endocarditis (IE) are unchanged over decades and nationwide data about the use of valve surgery do not exist. Methods We included patients with first-time IE (1999–2018) using Danish nationwide registries. Proportions of valve surgery were reported for calendar periods (1999–2003, 2004–2008, 2009–2...
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Background: We aimed to characterise the adaptive immune response to Mycobacterium abscessus complex (MABSC) and its cross-reactivity with Mycobacterium avium complex (MAC) and Mycobacterium bovis (Bacille Calmette-Guérin, BCG) in cystic fibrosis (CF) patients and non-CF controls in terms of lymphocyte proliferation and immunophenotyping, cytokine...
Article
Acute wounds, such as thermal injury, and chronic wounds are challenging for patients and the health care system around the world. Thermal injury of considerable size induces immunosuppression, which renders the patient susceptible to wound infections, but also in other foci like the airways and urinary tract. Infected thermal lesions can progress...
Article
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Infective endocarditis (IE) is a serious infection of the inner surface of heart, resulting from minor lesions in the endocardium. The damage induces a healing reaction, which leads to recruitment of fibrin and immune cells. This sterile healing vegetation can be colonized during temporary bacteremia, inducing IE. We have previously established a n...
Article
Infective endocarditis (IE) is one of the most severe infectious diseases with an in-hospital mortality of 20-25%. Several studies have shown, that the incidence of IE is increasing, and that patients now are older with a higher burden of comorbidities than previously. The diagnostic work-up is mainly based upon the presence of bacteraemia and echo...
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Patients with infective endocarditis (IE) form a heterogeneous group by age, co-morbidities and severity ranging from stable patients to patients with life-threatening complications with need for intensive care. A large proportion need surgical intervention. In-hospital mortality is 15-20%. The concept of using hyperbaric oxygen therapy (HBOT) in o...
Article
Chronic infections caused by microbial biofilms represent an important clinical challenge. The recalcitrance of microbial biofilms to antimicrobials and to the immune system is a major cause of persistence and clinical recurrence of these infections. In this Review, we present the extent of the clinical problem, and the mechanisms underlying the to...
Article
Background The Partial-Oral versus Intravenous Antibiotic Treatment of Endocarditis Trial (POET) found that partial-oral outpatient treatment was non-inferior to conventional in-hospital intravenous treatment in patients with left-sided infective endocarditis. We examined the impact of treatment strategy on levels of anxiety and depression. Method...
Article
Objectives The pathophysiology of chronic wounds is characterized by prolonged inflammation, low mitogenic-activity, high protease-/low inhibitor-activity, microbiota changes and biofilm formation, in combination with the etiology of the original insult. One strategy to promote healing is to terminate the parasitism-like-relationship between the bi...
Article
Objective To assess the prevalence and severity of anaemia in patients with left-sided infective endocarditis (IE) and association with mortality. Methods In the Partial Oral versus Intravenous Antibiotic Treatment of Endocarditis trial, 400 patients with IE were randomised to conventional or partial oral antibiotic treatment after stabilisation o...
Article
Infective endocarditis (IE) is a heart valve infection with high mortality rates. IE results from epithelial lesions, inducing sterile healing vegetations consisting of platelets, leucocytes and fibrin that are susceptible for colonization by temporary bacteremia. Clinical testing of new treatments for IE is difficult and fast models sparse. The pr...
Article
Animal models of human diseases are invaluable and inevitable elements in identifying and testing novel treatments of serious diseases, including severe infections. Planning and conducting investigator initiated human trials are generally accepted as being enormously challenging. In contrast, it is often underestimated how much planning, including...
Article
Staphylococcus aureus (SA) causes superficial and severe endovascular infections. The present in vitro study investigates the anti‐SA mechanisms of hyperbaric oxygen therapy (HBOT) on direct bacterial killing, antibiotic potentiation and polymorphonuclear leukocyte (PMN) enhancement. SA was exposed to isolated human PMNs, tobramycin, ciprofloxacin...
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Infective endocarditis (IE) is a life-threatening infective disease with increasing incidence worldwide. From early on, in the antibiotic era, it was recognized that high-dose and long-term antibiotic therapy was correlated to improved outcome. In addition, for several of the common microbial IE etiologies, the use of combination antibiotic therapy...
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Necrotizing soft-tissue infection (NSTI) is a rare, severe, and fast-progressing bacterial infection associated with a high risk of developing sepsis or septic shock. Increasing evidence indicates that oxidative stress is crucial in the development and progression of sepsis, but its role in NSTI specifically has not been investigated. Some patients...
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Objective Pseudomonas aeruginosa is known to contribute to the pathogenesis of chronic wounds by biofilm-establishment with increased tolerance to host response and antibiotics. The neutrophil-factor S100A8/A9 has a promising adjuvant effect when combined with ciprofloxacin, measured by quantitative bacteriology, and increased anti- and lowered pro...
Article
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Pseudomonas aeruginosa is a key pathogen of chronic infections in the lungs of cystic fibrosis patients and in patients suffering from chronic wounds of diverse aetiology. In these infections the bacteria congregate in biofilms and cannot be eradicated by standard antibiotic treatment or host immune responses. The persistent biofilms induce a hyper...
Article
The inflammatory response in patients with necrotizing soft-tissue infection (NSTI) is excessive and often causes collateral damage, thereby worsening disease severity and prognosis. Shedding of endothelial adhesion molecules may be a key regulatory mechanism to modulate the inflammatory response in septic NSTI patients. Hyperbaric oxygen (HBO 2 )...
Article
Background Left-sided infectious endocarditis (IE) has a high 1-year mortality. Anemia is a common finding in patients with IE, yet little is known about frequency, severity, and associated outcomes in this setting. Purpose To examine the relationship between Hemoglobin (Hgb) level measured at IE stabilization (time of randomization) in the Partia...
Article
Introduction Cystic fibrosis (CF) patients are at risk of acquiring chronic Pseudomonas aeruginosa lung infections. The biofilm mode of growth of P. aeruginosa induces tolerance to antibiotics and the host response; accordingly, treatment failure occurs. Supplemental azithromycin has proven beneficial in CF due to potential immunomodulatory mechani...
Article
Background IL‐2 is a pro‐inflammatory and a Th1 inducing cytokine, which is important for activation of the cell‐mediated immunity. IL‐2 in serum and sputum has been observed to be reduced in cystic fibrosis (CF) patients. The present IL‐2 treatment study of Pseudomonas aeruginosa (PA) lung infected mice was performed in order to evaluate the effec...
Article
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Normal wound healing occurs in three phases—the inflammatory, the proliferative, and the remodeling phase. Chronic wounds are, for unknown reasons, arrested in the inflammatory phase. Bacterial biofilms may cause chronicity by arresting healing in the inflammatory state by mechanisms not fully understood. Pseudomonas aeruginosa, a common wound path...
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Fast and accurate detection of causative agents of bloodstream infections remains a challenge of today's microbiology. We compared the performance of cutting‐edge technology based on polymerase chain reaction coupled with electrospray ionization‐mass spectrometry (PCR/ESI‐MS) with that of conventional broad‐range 16S rRNA PCR and blood culture to a...
Article
Background The optimal antibiotic treatment length for infective endocarditis (IE) is uncertain. International guidelines recommend treatment duration of up to six weeks for patients with left sided IE but are primarily based on historical data and expert opinion. Efficacies of modern therapies, fast recovery seen in many patients with IE and compl...
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Streptococcus gordonii and Streptococcus sanguinis belong to the Mitis group streptococci, which mostly are commensals in the human oral cavity. Though they are oral commensals, they can escape their niche and cause infective endocarditis, a severe infection with high mortality. Several virulence factors important for the development of infective e...
Article
Background: Transcatheter aortic valve implantation (TAVI) has been approved for the treatment of severe aortic stenosis since 2008 and recent trials have shown that TAVI is a least non-inferior to surgical aortic valve replacement (SAVR) with regards to short-term efficacy and safety in patients across all surgical risk profiles. Prosthetic valve...
Article
Background: Specific Pseudomonas aeruginosa (PA) precipitating immunoglobulin G antibodies in serum are correlated with PA biofilm infection and are used as diagnostic and prognostic markers in cystic fibrosis (CF). The aim of this study was to examine the change of PA antibody response in CF patients after bilateral sequential lung transplantatio...
Article
Background: Pseudomonas aeruginosa is difficult to eradicate from the lungs of cystic fibrosis (CF) patients due to biofilm formation. Organs and blood are independent pharmacokinetic (PK) compartments. Previously, we showed in vitro biofilms behave as independent compartments impacting the pharmacodynamics. The present study investigated this phe...
Article
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Bacteria and fungi show substantial increased recalcitrance when growing as infectious biofilms. Chronic infections caused by biofilm growing microorganisms is considered a major problem of modern medicine. New strategies are needed to improve antibiotic treatment of biofilms. We have improved antibiotic treatment of bacterial biofilms by reviving...
Article
Full-text available
Bacteria and fungi show substantial increased recalcitrance when growing as infectious biofilms. Chronic infections caused by biofilm growing microorganisms is considered a major problem of modern medicine. New strategies are needed to find new ways to improve antibiotic treatment of biofilms. We have improved antibiotic treatment of bacterial biof...
Presentation
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Background Increasing attention has been given to the risk of infective endocarditis (IE) in patients with certain blood stream infections (BSI). Previous studies have been conducted on selected patient cohorts, yet unselected data are sparse. Purpose To investigate the nationwide prevalence of diagnosed IE in BSIs with bacteria typically associat...
Poster
Full-text available
PURPOSE We examined the Pseudomonas aeruginosa (PA) antibody response in 20 chronically PA infected cystic fibrosis (CF) patients from the CF Centre Copenhagen after bilateral sequential lung transplantation (LTx). We hypothesized that the antibody response to PA would change after LTx due to removal of the infectious load and immunosuppressive the...
Article
Aims: Increasing attention has been given to the risk of infective endocarditis (IE) in patients with certain blood stream infections (BSIs). Previous studies have been conducted on selected patient cohorts, yet unselected data are sparse. We aimed to investigate the prevalence of IE in BSIs with bacteria typically associated with IE. Methods and...
Article
The majority of chronic wounds are associated with bacterial biofilms recalcitrant to antibiotics and host responses.Immunomodulatory S100A8/A9 is suppressed in P. aeruginosa biofilms infected wounds. We aimed at investigating a possible additive effect between S100A8/A9 and ciprofloxacin against biofilms. Materials/methods: Thirty-two mice were...
Article
Introduction: Bacteraemia in adult patients undergoing treatment for leukaemia is common and associated with profound morbidity and mortality. Infections related to the use of a central venous catheter (CVC) are difficult to eliminate with systemic antibiotics. Premature catheter removal is often due to retained biofilm infection. This study inves...
Article
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Background Staphylococcus aureus is the most frequent and fatal cause of left-sided infective endocarditis (IE). New treatment strategies are needed to improve the outcome. S. aureus coagulase promotes clot and fibrin formation. We hypothesized that dabigatran, could reduce valve vegetations and inflammation in S. aureus IE. Methods We used a rat...
Data
Cytokines and adhesion molecules expression in aortic valve endocarditis. (DOCX)
Data
Results of ROTEM performed in plasma samples. (DOCX)
Data
Extended Material, Method and Results section. (PDF)
Data
Flow cytometry of whole blood. Platelet-neutrophil complexes (PNC) (A), neutrophils (B) and total leukocyte count (TLC) (C) are shown for the two intervention groups. Horizontal lines represent means ± standard derivation. * indicate p < 0.05. n.s., non-significant. (TIF)
Data
Histopathological representative illustrations of catheter induced Staphylococcus aureus (S. aureus) infective endocarditis (IE). (A) Valve vegetation of severe S. aureus IE by hematoxylin and eosin stain (H&E) (Magnification x10). (B) fibrin (red) sequestering S. aureus in valve vegetations (x10) Martius Scarlet Blue (MSB). C) illustrating aortic...
Data
Histopathological illustrations from rats in the saline group. (A) Severe neutrophil infiltration of the aortic valve and subendothelial (hematoxylin and eosin (H&E), magnification x20) and (B) counterstained with Martius Scarlet Blue (MSB) where the collagen is strongly blue but no stains for fresh (yellow) or mature (red) fibrin. (C) Inflamed spl...
Data
Dabigatran inhibits growth of S. aureus in plasma. Growth curve of S. aureus incubated in plasma from rats at different dabigatran concentrations (25–730 μg/L) showing a delayed growth rate of S. aureus at high plasma dabigatran concentrations (544 and 730 μg/L), indicating a direct anti-S. aureus effect of dabigatran in plasma. P < 0.0001 at plasm...
Article
The discovery of antibiotic drugs is considered one of the previous century's most important medical discoveries (1). Appropriate use of antibiotics saves millions of lives each year and prevents infectious complications for numerous people. Still, infections kill unacceptable many people around the world, even in developed countries with easy acce...
Article
Published @ https://bestprac.dk/2019/04/30/mekanismer-i-det-humorale-immunrespons-mod-pseudomonas-aeruginosa-biofilminfektioner-hos-patienter-med-cystisk-fibrose/
Article
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The global spread of antimicrobial resistance and the increasing number of immune‐compromised patients are major challenges in modern medicine. Targeting bacterial virulence or the human host immune system to increase host defence are important strategies in the search for novel antimicrobial drugs. We investigated the inflammatory response of the...
Article
This letter describes outcomes of the POET trial at a median follow-up of 3.5 years. The authors found that in patients with endocarditis on the left side of the heart, a change from intravenous antibiotic treatment to early oral antibiotic treatment was not associated with delayed treatment failure.
Article
Full-text available
Mycobacterium abscessus complex can cause severe lung infections and has proven to be a serious threat to patients with cystic fibrosis and a challenge for clinicians due to difficulties in timely diagnosis and complex multidrug treatment regimes. Mycobacterial culture is the gold standard for diagnosis, but in most cystic fibrosis centers it is pe...
Data
Neutrophil chimerism of transplanted mice included in experiments. (A) Gating strategy for estimation of neutrophil chimerism in blood of bone-marrow transplanted mice 7 weeks post-transplant. (B) Results presented as the percent of donor derived neutrophils of total neutrophils in bone marrow transplanted mice included in experiments. Data from WT...
Data
Immune histochemical staining targeting lipocalin-2 in chimeric mice. Staining for lipocalin-2 of lungs from WT/WT, KO/KO, KO/WT, and WT/KO mice 3 weeks post-challenge with H37Rv M.tb. Pictures illustrate differential expression of lipocalin-2 in epithelial- and myeloid cells depending on chimeric composition.
Article
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Objective:: To compare matrix metalloproteinase (MMP)-9 and the antiproteinase tissue inhibitor of metalloproteinases (TIMP)-1 in wound fluids and sera from patients with chronic non-healing or acute healing wounds. In addition, the functional consequences on MMP-9 activity and general gelatinase activity were assessed. Method:: In this observat...
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Lipocalin-2 is a constituent of the neutrophil secondary granules and is expressed de novo by macrophages and epithelium in response to inflammation. Lipocalin-2 acts in a bacteriostatic fashion by binding iron-loaded siderophores required for bacterial growth. Mycobacterium tuberculosis (M.tb) produces siderophores that can be bound by lipocalin-2...
Article
BACKGROUND Patients with infective endocarditis on the left side of the heart are typically treated with intravenous antibiotic agents for up to 6 weeks. Whether a shift from intravenous to oral antibiotics once the patient is in stable condition would result in efficacy and safety similar to those with continued intravenous treatment is unknown. M...
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Several immunosuppressive drugs have been proposed for second-line treatment of steroid-refractory acute graft versus host disease (aGvHD) after allogeneic hematopoietic stem cell transplantation. However, the studies on these drugs are small, retrospective, uncontrolled and use different endpoints. Therefore, it remains unknown which treatment is...
Article
Although much work is being done to develop new treatments, research and knowledge regarding factors underlying implant‐related microbial colonization leading to infection are less comprehensive. Presence of microorganisms in and around implants clinically characterized as uninfected remains unknown. The objective of this study was to detect and id...
Article
Full-text available
Purpose of review: The major problem for cystic fibrosis patients is the recurrent and chronic infections of the lungs, determining their prognosis. The challenge from biofilm-growing bacteria and emerging viruses urge the microbiological laboratories to develop better and faster diagnostic tools. Of these, molecular diagnostics are rapidly develo...