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1.
Clin Transl Med ; 14(5): e1719, 2024 May.
Article in English | MEDLINE | ID: mdl-38778460

ABSTRACT

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.


Subject(s)
Cerebrovascular Disorders , Humans , Cerebrovascular Disorders/drug therapy , Cerebrovascular Disorders/metabolism , Ubiquitin/metabolism , Ubiquitination
2.
Eur J Cell Biol ; 103(2): 151401, 2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38442571

ABSTRACT

The facultative intracellular bacterium Listeria (L.) monocytogenes may cause severe diseases in humans and animals. The control of listeriosis/L. monocytogenes requires the concerted action of cells of the innate and adaptive immune systems. In this regard, cell-intrinsic immunity of infected cells, activated by the immune responses, is crucial for the control and elimination intracellular L. monocytogenes. Both the immune response against L. monocytogenes and cell intrinsic pathogen control are critically regulated by post-translational modifications exerted by the host ubiquitin system and ubiquitin-like modifiers (Ubls). In this review, we discuss our current understanding of the role of the ubiquitin system and Ubls in listeriosis, as well as future directions of research.

3.
PLoS One ; 19(2): e0297866, 2024.
Article in English | MEDLINE | ID: mdl-38408053

ABSTRACT

Vancomycin-resistant enterococci (VRE) occur in hospitalized patients, causing both infection and colonization. In recent years, there has been an increase in VRE in German and other hospitals, raising the question of how to control this epidemic best. To better understand the specific epidemiology and to guide infection control, we conducted a retrospective cohort study analyzing all patients with VRE at Hannover Medical School, a tertiary university clinic in Germany that specializes in solid organ transplantation. Epidemiologic and clinical characteristics of patients with VRE from 2015-2017 were collected. Basic epidemiologic parameters, including VRE incidence and incidence density, were calculated. Independent risk factors for nosocomial VRE infection compared to colonization were assessed using a logistic regression model. There were 1,492 VRE cases corresponding to 822 individual patients. The incidence was 0.8 VRE cases per 100 cases. A total of 536 (35.9%) of the 1,492 VRE cases were acquired nosocomially. Of the 1,492 cases, 912 cases had VRE-positive samples (894 Enterococcus (E.) faecium and 18 E. faecalis) in our hospital laboratory and the remaining cases were known VRE carriers. The vanB-phenotype was observed in 369 of the 894 (41.3%) E. faecium isolates and in 6 of the 18 (33.3%) E. faecalis isolates. There was an increase over time in the vanB-phenotype proportion in E. faecium (2015: 63 of 171, 36.8%, 2016: 115 of 322, 35.7% and 2017: 191 of 401, 47.6%). A total of 107 cases had a VRE infection (7.2% of all VRE cases) according to the criteria of the German National Reference Center for Surveillance of Nosocomial Infections. The remaining cases were only colonized. Among other factors, leukocytopenia (<1,000/µL), the use of a central venous catheter and the visceral surgery medical specialty were independently associated with nosocomial VRE infection. VRE imposed a relevant and increasing infection control burden at our hospital. Nosocomial VRE infection was predominantly found in certain medical specialties, such as hematology and oncology and visceral surgery. Infection control efforts should focus on these highly affected patient groups/specialties.


Subject(s)
Cross Infection , Enterococcus faecium , Gram-Positive Bacterial Infections , Vancomycin-Resistant Enterococci , Humans , Vancomycin-Resistant Enterococci/genetics , Hospitals, University , Retrospective Studies , Infection Control , Cross Infection/epidemiology , Gram-Positive Bacterial Infections/epidemiology , Anti-Bacterial Agents
4.
Microbiol Spectr ; 12(1): e0307923, 2024 Jan 11.
Article in English | MEDLINE | ID: mdl-38063385

ABSTRACT

IMPORTANCE: Antimicrobial resistance (AMR) poses a global threat and requires the exploration of underestimated treatment options. Nitroxoline, an effective broad-spectrum antibiotic, does not suffer from high resistance rates in the clinics but surprisingly, it is not heavily used yet. Our findings provide compelling evidence that Nitroxoline resistance renders bacteria unable to cause an infection in vivo, thereby reinvigorating the potential of Nitroxoline in combating AMR.


Subject(s)
Escherichia coli Infections , Nitroquinolines , Urinary Tract Infections , Humans , Escherichia coli , Anti-Infective Agents, Urinary , Urinary Tract Infections/microbiology , Virulence , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Escherichia coli Infections/drug therapy , Escherichia coli Infections/microbiology
5.
J Clin Invest ; 133(24)2023 Dec 15.
Article in English | MEDLINE | ID: mdl-37856217

ABSTRACT

A20 is a ubiquitin-modifying protein that negatively regulates NF-κB signaling. Mutations in A20/TNFAIP3 are associated with a variety of autoimmune diseases, including multiple sclerosis (MS). We found that deletion of A20 in central nervous system (CNS) endothelial cells (ECs) enhances experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. A20ΔCNS-EC mice showed increased numbers of CNS-infiltrating immune cells during neuroinflammation and in the steady state. While the integrity of the blood-brain barrier (BBB) was not impaired, we observed a strong activation of CNS-ECs in these mice, with dramatically increased levels of the adhesion molecules ICAM-1 and VCAM-1. We discovered ICOSL to be expressed by A20-deficient CNS-ECs, which we found to function as adhesion molecules. Silencing of ICOSL in CNS microvascular ECs partly reversed the phenotype of A20ΔCNS-EC mice without reaching statistical significance and delayed the onset of EAE symptoms in WT mice. In addition, blocking of ICOSL on primary mouse brain microvascular ECs impaired the adhesion of T cells in vitro. Taken together, we propose that CNS EC-ICOSL contributes to the firm adhesion of T cells to the BBB, promoting their entry into the CNS and eventually driving neuroinflammation.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental , Neuroinflammatory Diseases , Tumor Necrosis Factor alpha-Induced Protein 3 , Animals , Mice , Blood-Brain Barrier/metabolism , Central Nervous System/metabolism , Endothelial Cells/metabolism , Mice, Inbred C57BL , Multiple Sclerosis/metabolism , Neuroinflammatory Diseases/metabolism , T-Lymphocytes/metabolism , Inducible T-Cell Co-Stimulator Ligand/metabolism , Tumor Necrosis Factor alpha-Induced Protein 3/metabolism
6.
Adv Sci (Weinh) ; 10(28): e2301641, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37587766

ABSTRACT

Cerebral ischemic stroke is a leading cause of morbidity and mortality globally. However, the mechanisms underlying ischemic stroke injury remain poorly understood. Here, it is found that deficiency of the ubiquitin-specific protease USP25 significantly aggravate ischemic stroke injury in mice. USP25 has no impact on neuronal death under hypoxic conditions, but reduced ischemic stroke-induced neuronal loss and neurological deficits by inhibiting microglia-mediated neuroinflammation. Mechanistically, USP25 restricts the activation of NF-κB and MAPK signaling by regulating TAB2. As a deubiquitinating enzyme, USP25 removeds K63-specific polyubiquitin chains from TAB2. AAV9-mediated TAB2 knockdown ameliorates ischemic stroke injury and abolishes the effect of USP25 deletion. In both mouse and human brains, USP25 is markedly upregulated in microglia in the ischemic penumbra, implying a clinical relevance of USP25 in ischemic stroke. Collectively, USP25 is identified as a critical inhibitor of ischemic stroke injury and this data suggest USP25 may serve as a therapeutic target for ischemic stroke.

7.
Clin Transl Med ; 13(8): e1385, 2023 08.
Article in English | MEDLINE | ID: mdl-37608493

ABSTRACT

BACKGROUND: CCN6 is a matricellular protein that critically regulates the tumourigenesis and progression of breast cancer. Although the tumour-suppressive function of CCN6 has been extensively studied, molecular mechanisms regulating protein levels of CCN6 remain largely unclear. This study aims to investigate the regulation of CCN6 by ubiquitination and deubiquitinating enzymes (DUBs) in breast cancer. METHODS: A screening assay was performed to identify OTUB1 as the DUB for CCN6. Various biochemical methods were applied to elucidate the molecular mechanism of OTUB1 in the regulation of CCN6. The role of OTUB1-CCN6 interaction in breast cancer was studied with cell experiments and the allograft model. The correlation of OTUB1 and CCN6 in human breast cancer was determined by immunohistochemistry and Western blot. RESULTS: We found that CCN6 protein levels were controlled by the ubiquitin-proteasome system. The K48 ubiquitination and degradation of CCN6 was inhibited by OTUB1, which directly interacted with CCN6 through its linker domain. Furthermore, OTUB1 inhibited the ubiquitination of CCN6 in a non-canonical manner. Deletion of OTUB1, concomitant with reduced CCN6 abundance, increased the migration, proliferation and viability of breast cancer cells. Supplementation of CCN6 abolished the effect of OTUB1 deletion on breast cancer. Importantly, OTUB1 expression was downregulated in human breast cancer and positively correlated with CCN6 levels. CONCLUSION: This study identified OTUB1 as a novel regulator of CCN6 in breast cancer.


Subject(s)
CCN Intercellular Signaling Proteins , Carcinogenesis , Cell Transformation, Neoplastic , Deubiquitinating Enzymes , Humans , Blotting, Western , Cytoplasm , Proteasome Endopeptidase Complex , Deubiquitinating Enzymes/metabolism , CCN Intercellular Signaling Proteins/metabolism
8.
Neurol Res Pract ; 5(1): 44, 2023 Aug 31.
Article in English | MEDLINE | ID: mdl-37649122

ABSTRACT

INTRODUCTION: The incidence of community-acquired acute bacterial meningitis has decreased during the last decades. However, outcome remains poor with a significant proportion of patients not surviving and up to 50% of survivors suffering from long-term sequelae. These guidelines were developed by the Deutsche Gesellschaft für Neurologie (DGN) under guidance of the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF) to guide physicians through diagnostics and treatment of adult patients with acute bacterial meningitis. RECOMMENDATIONS: The most important recommendations are: (i) In patients with suspected acute bacterial meningitis, we recommend that lumbar cerebrospinal fluid (with simultaneous collection of serum to determine the cerebrospinal fluid-serum glucose index and blood cultures) is obtained immediately after the clinical examination (in the absence of severely impaired consciousness, focal neurological deficits, and/or new epileptic seizures). (ii) Next, we recommend application of dexamethasone and empiric antibiotics intravenously. (iii) The recommended initial empiric antibiotic regimen consists of ampicillin and a group 3a cephalosporin (e.g., ceftriaxone). (iv) In patients with severely impaired consciousness, new onset focal neurological deficits (e.g. hemiparesis) and/or patients with newly occurring epileptic seizures, we recommend that dexamethasone and antibiotics are started immediately after the collection of blood; we further recommend that -if the imaging findings do not indicate otherwise -a lumbar CSF sample is taken directly after imaging. (v) Due to the frequent occurrence of intracranial and systemic complications, we suggest that patients with acute bacterial meningitis are treated at an intensive care unit in the initial phase of the disease. In the case of impaired consciousness, we suggest that this is done at an intensive care unit with experience in the treatment of patients with severe CNS diseases. CONCLUSIONS: The German S2k-guidelines give up to date recommendations for workup, diagnostics and treatment in adult patients with acute bacterial meningitis.

9.
Cell Death Dis ; 14(7): 480, 2023 07 29.
Article in English | MEDLINE | ID: mdl-37516734

ABSTRACT

The cytokine tumor necrosis factor (TNF) critically regulates the intertwined cell death and pro-inflammatory signaling pathways of dendritic cells (DCs) via ubiquitin modification of central effector molecules, but the intrinsic molecular switches deciding on either pathway are incompletely defined. Here, we uncover that the ovarian tumor deubiquitinating enzyme 7b (OTUD7b) prevents TNF-induced apoptosis of DCs in infection, resulting in efficient priming of pathogen-specific CD8+ T cells. Mechanistically, OTUD7b stabilizes the E3 ligase TNF-receptor-associated factor 2 (TRAF2) in human and murine DCs by counteracting its K48-ubiquitination and proteasomal degradation. TRAF2 in turn facilitates K63-linked polyubiquitination of RIPK1, which mediates activation of NF-κB and MAP kinases, IL-12 production, and expression of anti-apoptotic cFLIP and Bcl-xL. We show that mice with DC-specific OTUD7b-deficiency displayed DC apoptosis and a failure to induce CD8+ T cell-mediated brain pathology, experimental cerebral malaria, in a murine malaria infection model. Together, our data identify the deubiquitinating enzyme OTUD7b as a central molecular switch deciding on survival of human and murine DCs and provides a rationale to manipulate DC responses by targeting their ubiquitin network downstream of the TNF receptor pathway.


Subject(s)
CD8-Positive T-Lymphocytes , Ubiquitin-Protein Ligases , Animals , Humans , Mice , Apoptosis , Dendritic Cells , Deubiquitinating Enzymes , TNF Receptor-Associated Factor 2 , Tumor Necrosis Factor-alpha/pharmacology , Ubiquitins
10.
Gut Microbes ; 14(1): 2149019, 2022.
Article in English | MEDLINE | ID: mdl-36416760

ABSTRACT

The bacteria-derived short-chain fatty acids (SCFAs) butyrate and propionate play important (distinct) roles in health and disease, and understanding the ecology of respective bacteria on a community-wide level is a top priority in microbiome research. Applying sequence data (metagenomics and 16S rRNA gene) to predict SCFAs production in vitro and in vivo, a clear split between butyrate- and propionate-forming bacteria was detected with only very few taxa exhibiting pathways for the production of both SCFAs. After in vitro growth of fecal communities from distinct donors (n = 8) on different substrates (n = 7), abundances of bacteria exhibiting pathways correlated with respective SCFA concentrations, in particular in the case of butyrate. For propionate, correlations were weaker, indicating that its production is less imprinted into the core metabolism compared with butyrate-forming bacteria. Longitudinal measurements in vivo (n = 5 time-points from 20 subjects) also revealed a correlation between abundances of pathway-carrying bacteria and concentrations of the two SCFAs. Additionally, lower bacterial cell concentrations, together with higher stool moisture, promoted overall bacterial activity (measured by flow cytometry and coverage patterns of metagenome-assembled genomes) that led to elevated SCFA concentrations with over-proportional levels of butyrate. Predictions on pathway abundances based on 16S rRNA gene data using our in-house database worked well, yielding similar results as metagenomic-based analyses. Our study indicates that stimulating growth of butyrate- and propionate-producing bacteria directly leads to more production of those compounds, which is governed by two functionally distinct bacterial groups facilitating the development of precision intervention strategies targeting either metabolite.


Subject(s)
Gastrointestinal Microbiome , Humans , Butyrates/metabolism , Propionates/metabolism , RNA, Ribosomal, 16S/genetics , Fatty Acids, Volatile/metabolism , Bacteria
11.
PLoS One ; 17(9): e0275087, 2022.
Article in English | MEDLINE | ID: mdl-36129948

ABSTRACT

In preterm and term infants who require intermediate or intensive care Methicillin-resistant Staphylococcus aureus (MRSA) infection can lead to significant morbidity. In this study MRSA colonization and infection were assessed in a mixed tertiary neonatal intensive and intermediate care unit in Germany over an 8-year period (2013-2020). We investigated patient-related factors, associated with nosocomial MRSA acquisition, and we discuss our infection control concept for MRSA. Of 3488 patients treated during the study period, 24 were MRSA positive patients, corresponding to 26 patient hospital stays. The incidence was 0.7 MRSA patients per 100 patients. The incidence density was 0.4 MRSA patient hospital stays per 1000 patient days. Twelve patients (50%) acquired MRSA in the hospital. One patient developed a hospital acquired MRSA bloodstream infection 9 days after birth (i.e., 0.03% of all patients on the ward during the study period). A total of 122 patients had to be screened to detect one MRSA positive patient. In a logistic regression model, the use of 3rd generation intravenous cephalosporin (cefotaxim) was associated with nosocomial MRSA acquisition compared with matched control patients who did not acquire MRSA. In sum, the burden of MRSA colonization and infection in the ward was low during the study period. A comprehensive infection control concept that included microbiologic colonization screening, prospective infection surveillance together with isolation and emphasis on basic hygiene measures is essential to handle MRSA in this specialized setting.


Subject(s)
Cross Infection , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Cefotaxime , Cephalosporins , Cross Infection/epidemiology , Cross Infection/microbiology , Cross Infection/prevention & control , Humans , Infant , Infant, Newborn , Infection Control , Prospective Studies , Retrospective Studies , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Staphylococcal Infections/prevention & control
12.
J Antimicrob Chemother ; 77(5): 1247-1253, 2022 04 27.
Article in English | MEDLINE | ID: mdl-35257174

ABSTRACT

OBJECTIVES: To identify novel carbapenem resistance mechanisms and their potential to spread among clinical isolates. METHODS: Four clinical isolates of Citrobacter freundii, Serratia marcescens and Raoultella planticola (n = 2) from one hospital in Central Germany were sent to the German National Reference Centre for Multidrug-resistant Gram-negative Bacteria for carbapenemase detection. Phenotypic tests indicated the presence of a metallo-ß-lactamase (MBL), but PCR for various MBL genes could not identify any. Using WGS data, a putative bla gene was identified. Its carbapenemase activity was verified by heterologous expression in an Escherichia coli cloning strain, with subsequent MIC determination by broth microdilution, as well as by in vitro hydrolysis assays using purified enzyme. RESULTS: WGS indicated the presence of a putative ß-lactamase with 48% amino acid identity to the subclass B1 MBL SPM-1. MIC studies confirmed that the novel enzyme formed a functional MBL, which was therefore designated as GMB-1 (German MBL). In vitro hydrolysis assays showed a lack of activity not only against aztreonam but also against ertapenem. WGS revealed that in all three species the blaGMB-1 gene was located on the chromosome as part of a genetic island with multiple ISs. CONCLUSIONS: The finding of GMB-1 once again shows that novel carbapenemases continue to emerge and make their way into clinically relevant species. The occurrence of GMB-1 in three different species demonstrates the extraordinary mobility of such genetic islands and their potential to spread carbapenemase genes into diverse genetic environments.


Subject(s)
Anti-Bacterial Agents , beta-Lactamases , Anti-Bacterial Agents/pharmacology , Aztreonam , Escherichia coli , Microbial Sensitivity Tests , beta-Lactamases/metabolism
13.
Trends Mol Med ; 28(4): 304-318, 2022 04.
Article in English | MEDLINE | ID: mdl-35177326

ABSTRACT

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disorder of the gastrointestinal tract. Although the pathophysiology of IBD is multifaceted, ubiquitination, a post-translational modification, has been shown to have essential roles in its pathogenesis and development. Ubiquitin-modifying enzymes (UMEs) work in synergy to orchestrate the optimal ubiquitination of target proteins, thereby maintaining intestinal homeostasis. Genome-wide association studies (GWAS) have identified multiple UME genes as IBD susceptibility loci, implying the importance of UMEs in IBD. Furthermore, accumulative evidence demonstrates that UMEs affect intestinal inflammation by regulating various aspects, such as intestinal barrier functions and immune responses. Considering the significant functions of UMEs in IBD, targeting UMEs could become a favorable therapeutic approach for IBD.


Subject(s)
Colitis, Ulcerative , Colitis , Crohn Disease , Inflammatory Bowel Diseases , Colitis/genetics , Colitis, Ulcerative/genetics , Crohn Disease/genetics , Genome-Wide Association Study , Humans , Inflammatory Bowel Diseases/genetics , Ubiquitin
14.
Mol Psychiatry ; 27(1): 259-268, 2022 01.
Article in English | MEDLINE | ID: mdl-34285347

ABSTRACT

Neurodegenerative diseases (NDs) are characterized by the aggregation of neurotoxic proteins in the central nervous system. Aberrant protein accumulation in NDs is largely caused by the dysfunction of the two principal protein catabolism pathways, the ubiquitin-proteasome system (UPS), and the autophagy-lysosomal pathway (ALP). The two protein quality control pathways are bridged by ubiquitination, a post-translational modification that can induce protein degradation via both the UPS and the ALP. Perturbed ubiquitination leads to the formation of toxic aggregates and inclusion bodies that are deleterious to neurons. Ubiquitination is promoted by a cascade of ubiquitinating enzymes and counter-regulated by deubiquitinating enzymes (DUBs). As fine-tuning regulators of ubiquitination and protein degradation, DUBs modulate the stability of ND-associated pathogenic proteins including amyloid ß protein, Tau, and α-synuclein. Besides, DUBs also influence ND-associated mitophagy, protein secretion, and neuroinflammation. Given the various and critical functions of DUBs in NDs, DUBs may become potential therapeutic targets for NDs.


Subject(s)
Neurodegenerative Diseases , Amyloid beta-Peptides/metabolism , Deubiquitinating Enzymes/genetics , Deubiquitinating Enzymes/metabolism , Humans , Proteasome Endopeptidase Complex/metabolism , Ubiquitin/metabolism , Ubiquitination
16.
Trends Microbiol ; 30(1): 22-33, 2022 01.
Article in English | MEDLINE | ID: mdl-34016513

ABSTRACT

With the aim of overcoming host immune responses, and to permit persistence, numerous bacterial and viral pathogens have evolved effective strategies to control the activity of ovarian tumor domain proteases (OTUs), a group of deubiquitinylases crucial for regulating ubiquitin-modified proteins. Due to the important role of eukaryotic OTUs in cellular physiology, it is not surprising that pathogens have evolutionarily developed effector proteins which mimic host OTUs. Here, we focus on recent findings that illustrate how pathogen-encoded OTUs modulate eukaryotic host proteins and how they are implicated in cellular dysregulation. Further, we discuss the biological effects of OTUs in the context of structural features and pharmacological targeting. We point out the potentiality of selective OTU inhibitors, which shield ubiquitin-binding sites, as pharmacologic targets to treat harmful infections.


Subject(s)
Ovarian Neoplasms , Peptide Hydrolases , Humans , Peptide Hydrolases/metabolism , Protein Binding , Ubiquitin/chemistry , Ubiquitin/metabolism
17.
BMC Infect Dis ; 21(1): 1196, 2021 Nov 27.
Article in English | MEDLINE | ID: mdl-34837973

ABSTRACT

BACKGROUND: Carbapenem resistant (CR) Klebsiella pneumoniae (Kp) and Acinetobacter baumannii (Ab) are emerging multidrug resistant bacteria with very limited treatment options in case of infection. Both are well-known causes of nosocomial infections and outbreaks in healthcare facilities. METHODS: A retrospective study was conducted to investigate the epidemiology of inpatients with CR Kp and CR Ab in a 1500-bed German university hospital from 2015 to 2019. We present our infection control concept including a weekly microbiologic screening for patients who shared the ward with a CR Kp or CR Ab index patient. RESULTS: Within 5 years, 141 CR Kp and 60 CR Ab cases were hospitalized corresponding to 118 unique patients (74 patients with CR Kp, 39 patients with CR Ab and 5 patients with both CR Ab and CR Kp). The mean incidence was 0.045 (CR Kp) and 0.019 (CR Ab) per 100 inpatient cases, respectively. Nosocomial acquisition occurred in 53 cases (37.6%) of the CR Kp group and in 12 cases (20.0%) of the CR Ab group. Clinical infection occurred in 24 cases (17.0%) of the CR Kp group and in 21 cases (35.0%) of the CR Ab group. 14 cases (9.9%) of the CR Kp group and 29 cases (48.3%) of the CR Ab group had a history of a hospital stay abroad within 12 months prior to admission to our hospital. The weekly microbiologic screening revealed 4 CR Kp cases caused by nosocomial transmission that would have been missed without repetitive screening. CONCLUSIONS: CR Kp and CR Ab cases occurred infrequently. A history of a hospital stay abroad, particularly in the CR Ab group, warrants pre-emptive infection control measures. The weekly microbiologic screening needs further evaluation in terms of its efficiency.


Subject(s)
Acinetobacter baumannii , Klebsiella Infections , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Carbapenems/pharmacology , Carbapenems/therapeutic use , Hospitals, University , Humans , Infection Control , Klebsiella Infections/drug therapy , Klebsiella Infections/epidemiology , Klebsiella pneumoniae , Retrospective Studies
18.
Front Immunol ; 12: 724855, 2021.
Article in English | MEDLINE | ID: mdl-34659211

ABSTRACT

The adhesion and degranulation-promoting adaptor protein (ADAP) serves as a multifunctional scaffold and is involved in the formation of immune signaling complexes. To date, only limited data exist regarding the role of ADAP in pathogen-specific immunity during in vivo infection, and its contribution in phagocyte-mediated antibacterial immunity remains elusive. Here, we show that mice lacking ADAP (ADAPko) are highly susceptible to the infection with the intracellular pathogen Listeria monocytogenes (Lm) by showing enhanced immunopathology in infected tissues together with increased morbidity, mortality, and excessive infiltration of neutrophils and monocytes. Despite high phagocyte numbers in the spleen and liver, ADAPko mice only inefficiently controlled pathogen growth, hinting at a functional impairment of infection-primed phagocytes in the ADAP-deficient host. Flow cytometric analysis of hallmark pro-inflammatory mediators and unbiased whole genome transcriptional profiling of neutrophils and inflammatory monocytes uncovered broad molecular alterations in the inflammatory program in both phagocyte subsets following their activation in the ADAP-deficient host. Strikingly, ex vivo phagocytosis assay revealed impaired phagocytic capacity of neutrophils derived from Lm-infected ADAPko mice. Together, our data suggest that an alternative priming of phagocytes in ADAP-deficient mice during Lm infection induces marked alterations in the inflammatory profile of neutrophils and inflammatory monocytes that contribute to enhanced immunopathology while limiting their capacity to eliminate the pathogen and to prevent the fatal outcome of the infection.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Listeria monocytogenes/immunology , Listeriosis/immunology , Phagocytes/immunology , Adaptor Proteins, Signal Transducing/metabolism , Animals , Disease Models, Animal , Disease Susceptibility , Female , Immunity , Listeriosis/metabolism , Listeriosis/microbiology , Liver/metabolism , Male , Mice , Mice, Knockout , Phagocytes/metabolism , Phenotype , Spleen/metabolism
19.
Cell Host Microbe ; 29(11): 1663-1679.e7, 2021 11 10.
Article in English | MEDLINE | ID: mdl-34610293

ABSTRACT

Gut colonization with multidrug-resistant (MDR) bacteria enhances the risk of bloodstream infections in susceptible individuals. We demonstrate highly variable degrees of ex vivo colonization resistance against a carbapenem-resistant Klebsiella pneumoniae strain in human feces samples and subsequently isolate diverse K. oxytoca strains from protected donors. Several of these K. oxytoca strains reduce gut colonization of MDR K. pneumoniae strains in antibiotic-treated and gnotobiotic mouse models. Comparative analysis of K. oxytoca strains coupled with CRISPR-Cas9-mediated deletion of casA, a protein essential for utilization of selected beta-glucosides, identified competition for specific carbohydrates as key in promoting colonization resistance. In addition to direct competition between K. oxytoca and K. pneumoniae, cooperation with additional commensals is required to reestablish full colonization resistance and gut decolonization. Finally, humanized microbiota mice generated from K. pneumoniae-susceptible donors are protected by K. oxytoca administration, demonstrating the potential of commensal K. oxytoca strains as next-generation probiotics.


Subject(s)
Carbohydrate Metabolism , Feces/microbiology , Gastrointestinal Tract/microbiology , Klebsiella oxytoca/physiology , Klebsiella pneumoniae/growth & development , Microbial Interactions , Adaptive Immunity , Adult , Animals , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Child , Drug Resistance, Multiple, Bacterial , Gastrointestinal Microbiome , Germ-Free Life , Glucosides/metabolism , Humans , Klebsiella Infections/immunology , Klebsiella Infections/microbiology , Klebsiella oxytoca/genetics , Klebsiella oxytoca/isolation & purification , Klebsiella pneumoniae/drug effects , Mice , Mice, Inbred C57BL
20.
EXCLI J ; 20: 851-862, 2021.
Article in English | MEDLINE | ID: mdl-34177407

ABSTRACT

Nocardiosis is a rare but life-threatening infection caused by aerobic Actinomycetes of the genus Nocardia particularly affecting immunocompromised hosts. The identification of Nocardia ssp. and antibiotic susceptibility testing by standard microbiological methods are incomplete and molecular techniques may improve diagnostics. We studied 39 Nocardia strains isolated from 33 patients between 2000 and 2018. Twenty-four patients (72.7 %) were immunocompromised. Whole genome sequencing (WGS) revealed a broad taxonomic range of those isolates spanning 13 different species, including four strains that belonged to three novel species based on average nucleotide identity (ANI < 95 % with currently available genome sequences). 16S rRNA gene analyses mirrored WGS results. Conventional MALDI-TOF analysis correctly identified 29 isolates at the species level (74.4 %). Our advanced protocol with formic acid and acetonitrile treatment increased identification to 35 isolates (89.7 %). Antibiotic resistance was tested using both a microdilution method and MIC strip testing. Results were in good concordance with an overall trimethoprim-sulfamethoxazole (SXT) resistance rate of 13.5 %. WGS of a SXT resistant N. farcinica isolate showed a deletion of several amino acids in a homolog of dihydropteroate synthase (FolP2) that was not seen in sensitive members of this species. Diversity of Nocardia isolates was high and involved many different species, suggesting that this taxon has broadly distributed mechanisms for infecting individuals. Widely applicable diagnostic methods including MALDI-TOF and 16S rRNA gene analyses correctly identified most strains. WGS additionally revealed molecular insights into SXT resistance mechanisms of clinical Nocardia isolates highlighting the potential application of (meta)genomic-based diagnostics in the future.

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