The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
Kenneth V. I. Rolston - One of the best experts on this subject based on the ideXlab platform.
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Staphylococcus lugdunensis infections, filling in the gaps: a 3-year retrospective review from a comprehensive cancer center
Supportive Care in Cancer, 2017Co-Authors: Lior Nesher, Jeffery Tarrand, Kenneth V. I. RolstonAbstract:ObjectiveStaphylococcus lugdunensis is considered to be more aggressive than other coagulase-negative staphylococci (CoNS). There are gaps in knowledge regarding the importance of isolating S. lugdunensis from different sources and in different patient subsets. Our objective was to describe the spectrum, clinical manifestations, and outcomes of infections caused by S. lugdunensis in patients with cancer.MethodsA retrospective review of all cancer patients from whom S. lugdunensis was isolated in a pure culture from clinically significant sites.ResultsBetween 2011 and 2014, 2263 CoNS were isolated, of them 45 S. lugdunensis were isolated in a pure culture and were included in this analysis. Only three patients were neutropenic. Skin and skin structure infections (SSSIs) occurred most often (36 cases) followed by five blood stream infections, one of which had destructive endocarditis and four infections at other sites. Of the 36 SSSIs, 29 were related to surgical or invasive procedures, and six of these involved an Implanted Medical Device. All isolates were susceptible to vancomycin, 98% to levofloxacin and 89% to oxacillin. All patients responded to the therapy.ConclusionsCancer patients including those with neutropenia do not appear to have an increased frequency of infections caused by S. lugdunensis. SSSIs are predominant and are often associated with surgical procedures and/or Implanted Medical Devices. Blood stream infections caused by S. lugdunensis are uncommon but may have an increased rate of serious complications such as endocarditis. Nevertheless, these organisms are generally susceptible to multiple classes of antimicrobial agents, and the overall response to therapy is high.
Lior Nesher - One of the best experts on this subject based on the ideXlab platform.
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Staphylococcus lugdunensis infections, filling in the gaps: a 3-year retrospective review from a comprehensive cancer center
Supportive Care in Cancer, 2017Co-Authors: Lior Nesher, Jeffery Tarrand, Kenneth V. I. RolstonAbstract:ObjectiveStaphylococcus lugdunensis is considered to be more aggressive than other coagulase-negative staphylococci (CoNS). There are gaps in knowledge regarding the importance of isolating S. lugdunensis from different sources and in different patient subsets. Our objective was to describe the spectrum, clinical manifestations, and outcomes of infections caused by S. lugdunensis in patients with cancer.MethodsA retrospective review of all cancer patients from whom S. lugdunensis was isolated in a pure culture from clinically significant sites.ResultsBetween 2011 and 2014, 2263 CoNS were isolated, of them 45 S. lugdunensis were isolated in a pure culture and were included in this analysis. Only three patients were neutropenic. Skin and skin structure infections (SSSIs) occurred most often (36 cases) followed by five blood stream infections, one of which had destructive endocarditis and four infections at other sites. Of the 36 SSSIs, 29 were related to surgical or invasive procedures, and six of these involved an Implanted Medical Device. All isolates were susceptible to vancomycin, 98% to levofloxacin and 89% to oxacillin. All patients responded to the therapy.ConclusionsCancer patients including those with neutropenia do not appear to have an increased frequency of infections caused by S. lugdunensis. SSSIs are predominant and are often associated with surgical procedures and/or Implanted Medical Devices. Blood stream infections caused by S. lugdunensis are uncommon but may have an increased rate of serious complications such as endocarditis. Nevertheless, these organisms are generally susceptible to multiple classes of antimicrobial agents, and the overall response to therapy is high.
Yasmine Zerdoumi - One of the best experts on this subject based on the ideXlab platform.
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Role of the LytSR Two-Component Regulatory System in Staphylococcus lugdunensis Biofilm Formation and Pathogenesis
Frontiers in microbiology, 2020Co-Authors: Sandrine Dahyot, Virginie Oxaran, Maïté Niepceron, Eddy Dupart, Stéphanie Legris, Laurie Destruel, Jennifer Didi, Thomas Clamens, Olivier Lesouhaitier, Yasmine ZerdoumiAbstract:Staphylococcus lugdunensis is a coagulase negative Staphylococcus recognized as a virulent pathogen. It is responsible for a wide variety of infections, some of which are associated with biofilm production, such as Implanted Medical Device infections or endocarditis. However, little is known about S. lugdunensis regulation of virulence factor expression. Two-component regulatory systems (TCS) play a critical role in bacterial adaptation, survival, and virulence. Among them, LytSR is widely conserved but has variable roles in different organisms, all connected to metabolism or cell death and lysis occurring during biofilm development. Therefore, we investigated here the functions of LytSR in S. lugdunensis pathogenesis. Deletion of lytSR in S. lugdunensis DSM 4804 strain did not alter either susceptibility to Triton X-100 induced autolysis or death induced by antibiotics targeting cell wall synthesis. Interestingly, ΔlytSR biofilm was characterized by a lower biomass, a lack of tower structures, and a higher rate of dead cells compared to the wild-type strain. Virulence toward Caenorhabditis elegans using a slow-killing assay was significantly reduced for the mutant compared to the wild-type strain. By contrast, the deletion of lytSR had no effect on the cytotoxicity of S. lugdunensis toward the human keratinocyte cell line HaCaT. Transcriptional analyses conducted at mid- and late-exponential phases showed that lytSR deletion affected the expression of 286 genes. Most of them were involved in basic functions such as the metabolism of amino acids, carbohydrates, and nucleotides. Furthermore, LytSR appeared to be involved in the regulation of genes encoding known or putative virulence and colonization factors, including the fibrinogen-binding protein Fbl, the major autolysin AtlL, and the type VII secretion system. Overall, our data suggest that the LytSR TCS is implicated in S. lugdunensis pathogenesis, through its involvement in biofilm formation and potentially by the control of genes encoding putative virulence factors.
Philip S Stewart - One of the best experts on this subject based on the ideXlab platform.
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direct microscopic observation of human neutrophil staphylococcus aureus interaction in vitro suggests a potential mechanism for initiation of biofilm infection on an Implanted Medical Device
Infection and Immunity, 2019Co-Authors: Niranjan Ghimire, Brian A Pettygrove, Kyler B Pallister, James Stangeland, Shelby Stanhope, Isaac Klapper, Jovanka M Voyich, Philip S StewartAbstract:The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil:bacteria number ratio exceeded approximately one. When pre-attached bacteria were given a head start and allowed to grow for three hours prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head start experiments, aggregates of bacterial biofilm with areas of 50 μm2 or larger formed and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O2. SIGNIFICANCE Bacteria or yeast that form biofilms on Implanted Medical Devices such as artificial hip joints cause troublesome infections. These Device-associated infections are persistent because biofilm-embedded microorganisms are protected from antibiotics and host defenses. Three decades of research in antimicrobial coatings and non-stick surfaces have not yet solved the biofilm infection problem. Here we show in a model system that neutrophils can effectively clear contaminating Staphylococcus aureus bacteria from an abiotic surface, but they must be delivered quickly and in sufficient numbers. If neutrophil recruitment is delayed, undiscovered bacteria grow and form aggregates that evade engulfment and killing by white blood cells. This work opens a pathway to preventing infections on Implanted Medical Devices by transiently boosting innate immune defenses.
Jeffery Tarrand - One of the best experts on this subject based on the ideXlab platform.
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Staphylococcus lugdunensis infections, filling in the gaps: a 3-year retrospective review from a comprehensive cancer center
Supportive Care in Cancer, 2017Co-Authors: Lior Nesher, Jeffery Tarrand, Kenneth V. I. RolstonAbstract:ObjectiveStaphylococcus lugdunensis is considered to be more aggressive than other coagulase-negative staphylococci (CoNS). There are gaps in knowledge regarding the importance of isolating S. lugdunensis from different sources and in different patient subsets. Our objective was to describe the spectrum, clinical manifestations, and outcomes of infections caused by S. lugdunensis in patients with cancer.MethodsA retrospective review of all cancer patients from whom S. lugdunensis was isolated in a pure culture from clinically significant sites.ResultsBetween 2011 and 2014, 2263 CoNS were isolated, of them 45 S. lugdunensis were isolated in a pure culture and were included in this analysis. Only three patients were neutropenic. Skin and skin structure infections (SSSIs) occurred most often (36 cases) followed by five blood stream infections, one of which had destructive endocarditis and four infections at other sites. Of the 36 SSSIs, 29 were related to surgical or invasive procedures, and six of these involved an Implanted Medical Device. All isolates were susceptible to vancomycin, 98% to levofloxacin and 89% to oxacillin. All patients responded to the therapy.ConclusionsCancer patients including those with neutropenia do not appear to have an increased frequency of infections caused by S. lugdunensis. SSSIs are predominant and are often associated with surgical procedures and/or Implanted Medical Devices. Blood stream infections caused by S. lugdunensis are uncommon but may have an increased rate of serious complications such as endocarditis. Nevertheless, these organisms are generally susceptible to multiple classes of antimicrobial agents, and the overall response to therapy is high.
