The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Jean S Chia - One of the best experts on this subject based on the ideXlab platform.
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streptococcus mutans autolysin atla is a fibronectin binding protein and contributes to Bacterial Survival in the bloodstream and virulence for infective endocarditis
Molecular Microbiology, 2009Co-Authors: Chiau Jing Jung, Quan H Zheng, Ya Hsiung Shieh, Chi Shuan Lin, Jean S ChiaAbstract:Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to Bacterial resistance to phagocytosis and Survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance Bacterial Survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced Survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced Survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.
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Streptococcus mutans autolysin AtlA is a fibronectin‐binding protein and contributes to Bacterial Survival in the bloodstream and virulence for infective endocarditis
Molecular microbiology, 2009Co-Authors: Chiau Jing Jung, Quan H Zheng, Ya Hsiung Shieh, Chi Shuan Lin, Jean S ChiaAbstract:Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to Bacterial resistance to phagocytosis and Survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance Bacterial Survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced Survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced Survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.
Jan Kluytmans - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of an in vitro model with a novel statistical approach to measure differences in Bacterial Survival of extended-spectrum β-lactamase-producing Escherichia coli on an inanimate surface
Antimicrobial Resistance & Infection Control, 2019Co-Authors: Veronica Weterings, Jacobien Veenemans, Amanda Kleefman, Marjolein Kluytmans-van Bergh, Paul Mulder, Carlo Verhulst, Ina Willemsen, Jan KluytmansAbstract:Background The role of environmental contamination in the transmission of Enterobacteriaceae is increasingly recognized. However, factors influencing the duration of Survival in the environment have not yet been extensively studied. In this study, we developed and evaluated an in vitro model with a novel statistical approach to accurately measure differences in Bacterial Survival, that can be used to model the effects of multiple factors/conditions in future experiments. Methods Two extended-spectrum β-lactamase (ESBL)-producing Escherichia coli ( E. coli ) isolates were used for this in vitro experiment: a CTX-M-15-producing E. coli sequence type (ST) 131 and a CTX-M-1-producing E. coli ST10 isolate. Each strain was 1:1 diluted in sterile water, sterile saline or sheep blood. Cover glasses (18 × 18 mm) were inoculated with the dilution and subsequently kept at room temperature. Bacterial Survival on the glasses was determined hourly during the first day, once daily during the following 6 days, and from day 7 on, once weekly up to 100 days. The experiment was repeated six times for each strain, per suspension fluid. Results Viable bacteria could be detected up to 70 days. A biphasic Survival curve for all suspension fluids was observed, whereby there was a rapid decrease in the number of viable bacteria in the first 7 h, followed by a much slower decrease in the subsequent days. Conclusions We found a difference in Survival probability between E. coli ST10 and ST131, with a higher proportion of viable bacteria remaining after 7 h for ST131, particularly in sheep blood.
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Evaluation of an in vitro model with a novel statistical approach to measure differences in Bacterial Survival of extended-spectrum β -lactamase-producing Escherichia coli on an inanimate surface
Antimicrobial resistance and infection control, 2019Co-Authors: Veronica Weterings, Jacobien Veenemans, Amanda Kleefman, Carlo Verhulst, Ina Willemsen, Marjolein F. Q. Kluytmans-van Den Bergh, Paul G.h. Mulder, Jan KluytmansAbstract:The role of environmental contamination in the transmission of Enterobacteriaceae is increasingly recognized. However, factors influencing the duration of Survival in the environment have not yet been extensively studied. In this study, we developed and evaluated an in vitro model with a novel statistical approach to accurately measure differences in Bacterial Survival, that can be used to model the effects of multiple factors/conditions in future experiments. Two extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) isolates were used for this in vitro experiment: a CTX-M-15-producing E. coli sequence type (ST) 131 and a CTX-M-1-producing E. coli ST10 isolate. Each strain was 1:1 diluted in sterile water, sterile saline or sheep blood. Cover glasses (18 × 18 mm) were inoculated with the dilution and subsequently kept at room temperature. Bacterial Survival on the glasses was determined hourly during the first day, once daily during the following 6 days, and from day 7 on, once weekly up to 100 days. The experiment was repeated six times for each strain, per suspension fluid. Viable bacteria could be detected up to 70 days. A biphasic Survival curve for all suspension fluids was observed, whereby there was a rapid decrease in the number of viable bacteria in the first 7 h, followed by a much slower decrease in the subsequent days. We found a difference in Survival probability between E. coli ST10 and ST131, with a higher proportion of viable bacteria remaining after 7 h for ST131, particularly in sheep blood.
Chiau Jing Jung - One of the best experts on this subject based on the ideXlab platform.
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streptococcus mutans autolysin atla is a fibronectin binding protein and contributes to Bacterial Survival in the bloodstream and virulence for infective endocarditis
Molecular Microbiology, 2009Co-Authors: Chiau Jing Jung, Quan H Zheng, Ya Hsiung Shieh, Chi Shuan Lin, Jean S ChiaAbstract:Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to Bacterial resistance to phagocytosis and Survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance Bacterial Survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced Survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced Survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.
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Streptococcus mutans autolysin AtlA is a fibronectin‐binding protein and contributes to Bacterial Survival in the bloodstream and virulence for infective endocarditis
Molecular microbiology, 2009Co-Authors: Chiau Jing Jung, Quan H Zheng, Ya Hsiung Shieh, Chi Shuan Lin, Jean S ChiaAbstract:Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to Bacterial resistance to phagocytosis and Survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance Bacterial Survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced Survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced Survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.
James E. Casanova - One of the best experts on this subject based on the ideXlab platform.
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Activation of focal adhesion kinase by Salmonella suppresses autophagy via an Akt/mTOR signaling pathway and promotes Bacterial Survival in macrophages.
PLoS pathogens, 2014Co-Authors: Katherine A. Owen, Corey B. Meyer, Amy H. Bouton, James E. CasanovaAbstract:Autophagy has emerged as an important antimicrobial host defense mechanism that not only orchestrates the systemic immune response, but also functions in a cell autonomous manner to directly eliminate invading pathogens. Pathogenic bacteria such as Salmonella have evolved adaptations to protect themselves from autophagic elimination. Here we show that signaling through the non-receptor tyrosine kinase focal adhesion kinase (FAK) is actively manipulated by the Salmonella SPI-2 system in macrophages to promote intracellular Survival. In wild-type macrophages, FAK is recruited to the surface of the Salmonella-containing vacuole (SCV), leading to amplified signaling through the Akt-mTOR axis and inhibition of the autophagic response. In FAK-deficient macrophages, Akt/mTOR signaling is attenuated and autophagic capture of intracellular bacteria is enhanced, resulting in reduced Bacterial Survival. We further demonstrate that enhanced autophagy in FAK−/− macrophages requires the activity of Atg5 and ULK1 in a process that is distinct from LC3-assisted phagocytosis (LAP). In vivo, selective knockout of FAK in macrophages resulted in more rapid clearance of bacteria from tissues after oral infection with S. typhimurium. Clearance was correlated with reduced infiltration of inflammatory cell types into infected tissues and reduced tissue damage. Together, these data demonstrate that FAK is specifically targeted by S. typhimurium as a novel means of suppressing autophagy in macrophages, thereby enhancing their intracellular Survival.
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activation of focal adhesion kinase by salmonella suppresses autophagy via an akt mtor signaling pathway and promotes Bacterial Survival in macrophages
PLOS Pathogens, 2014Co-Authors: Katherine A. Owen, Corey B. Meyer, Amy H. Bouton, James E. CasanovaAbstract:Autophagy has emerged as an important antimicrobial host defense mechanism that not only orchestrates the systemic immune response, but also functions in a cell autonomous manner to directly eliminate invading pathogens. Pathogenic bacteria such as Salmonella have evolved adaptations to protect themselves from autophagic elimination. Here we show that signaling through the non-receptor tyrosine kinase focal adhesion kinase (FAK) is actively manipulated by the Salmonella SPI-2 system in macrophages to promote intracellular Survival. In wild-type macrophages, FAK is recruited to the surface of the Salmonella-containing vacuole (SCV), leading to amplified signaling through the Akt-mTOR axis and inhibition of the autophagic response. In FAK-deficient macrophages, Akt/mTOR signaling is attenuated and autophagic capture of intracellular bacteria is enhanced, resulting in reduced Bacterial Survival. We further demonstrate that enhanced autophagy in FAK−/− macrophages requires the activity of Atg5 and ULK1 in a process that is distinct from LC3-assisted phagocytosis (LAP). In vivo, selective knockout of FAK in macrophages resulted in more rapid clearance of bacteria from tissues after oral infection with S. typhimurium. Clearance was correlated with reduced infiltration of inflammatory cell types into infected tissues and reduced tissue damage. Together, these data demonstrate that FAK is specifically targeted by S. typhimurium as a novel means of suppressing autophagy in macrophages, thereby enhancing their intracellular Survival.
Veronica Weterings - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of an in vitro model with a novel statistical approach to measure differences in Bacterial Survival of extended-spectrum β-lactamase-producing Escherichia coli on an inanimate surface
Antimicrobial Resistance & Infection Control, 2019Co-Authors: Veronica Weterings, Jacobien Veenemans, Amanda Kleefman, Marjolein Kluytmans-van Bergh, Paul Mulder, Carlo Verhulst, Ina Willemsen, Jan KluytmansAbstract:Background The role of environmental contamination in the transmission of Enterobacteriaceae is increasingly recognized. However, factors influencing the duration of Survival in the environment have not yet been extensively studied. In this study, we developed and evaluated an in vitro model with a novel statistical approach to accurately measure differences in Bacterial Survival, that can be used to model the effects of multiple factors/conditions in future experiments. Methods Two extended-spectrum β-lactamase (ESBL)-producing Escherichia coli ( E. coli ) isolates were used for this in vitro experiment: a CTX-M-15-producing E. coli sequence type (ST) 131 and a CTX-M-1-producing E. coli ST10 isolate. Each strain was 1:1 diluted in sterile water, sterile saline or sheep blood. Cover glasses (18 × 18 mm) were inoculated with the dilution and subsequently kept at room temperature. Bacterial Survival on the glasses was determined hourly during the first day, once daily during the following 6 days, and from day 7 on, once weekly up to 100 days. The experiment was repeated six times for each strain, per suspension fluid. Results Viable bacteria could be detected up to 70 days. A biphasic Survival curve for all suspension fluids was observed, whereby there was a rapid decrease in the number of viable bacteria in the first 7 h, followed by a much slower decrease in the subsequent days. Conclusions We found a difference in Survival probability between E. coli ST10 and ST131, with a higher proportion of viable bacteria remaining after 7 h for ST131, particularly in sheep blood.
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Evaluation of an in vitro model with a novel statistical approach to measure differences in Bacterial Survival of extended-spectrum β -lactamase-producing Escherichia coli on an inanimate surface
Antimicrobial resistance and infection control, 2019Co-Authors: Veronica Weterings, Jacobien Veenemans, Amanda Kleefman, Carlo Verhulst, Ina Willemsen, Marjolein F. Q. Kluytmans-van Den Bergh, Paul G.h. Mulder, Jan KluytmansAbstract:The role of environmental contamination in the transmission of Enterobacteriaceae is increasingly recognized. However, factors influencing the duration of Survival in the environment have not yet been extensively studied. In this study, we developed and evaluated an in vitro model with a novel statistical approach to accurately measure differences in Bacterial Survival, that can be used to model the effects of multiple factors/conditions in future experiments. Two extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) isolates were used for this in vitro experiment: a CTX-M-15-producing E. coli sequence type (ST) 131 and a CTX-M-1-producing E. coli ST10 isolate. Each strain was 1:1 diluted in sterile water, sterile saline or sheep blood. Cover glasses (18 × 18 mm) were inoculated with the dilution and subsequently kept at room temperature. Bacterial Survival on the glasses was determined hourly during the first day, once daily during the following 6 days, and from day 7 on, once weekly up to 100 days. The experiment was repeated six times for each strain, per suspension fluid. Viable bacteria could be detected up to 70 days. A biphasic Survival curve for all suspension fluids was observed, whereby there was a rapid decrease in the number of viable bacteria in the first 7 h, followed by a much slower decrease in the subsequent days. We found a difference in Survival probability between E. coli ST10 and ST131, with a higher proportion of viable bacteria remaining after 7 h for ST131, particularly in sheep blood.