The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Philippe J Sansonetti - One of the best experts on this subject based on the ideXlab platform.
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Rhinoscleroma pathogenesis the type k3 capsule of klebsiella Rhinoscleromatis is a virulence factor not involved in mikulicz cells formation
PLOS Neglected Tropical Diseases, 2018Co-Authors: Barbara Corelli, Ana S Almeida, Fabiane Sonego, Virginia Castiglia, Cindy Fevre, Sylvain Brisse, Philippe J SansonettiAbstract:Rhinoscleroma is a human specific chronic granulomatous infection of the nose and upper airways caused by the Gram-negative bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. Although considered a rare disease, it is endemic in low-income countries where hygienic conditions are poor. A hallmark of this pathology is the appearance of atypical foamy monocytes called Mikulicz cells. However, the pathogenesis of Rhinoscleroma remains poorly investigated. Capsule polysaccharide (CPS) is a prominent virulence factor in bacteria. All K. Rhinoscleromatis strains are of K3 serotype, suggesting that CPS can be an important driver of Rhinoscleroma disease. In this study, we describe the creation of the first mutant of K. Rhinoscleromatis, inactivated in its capsule export machinery. Using a murine model recapitulating the formation of Mikulicz cells in lungs, we observed that a K. Rhinoscleromatis CPS mutant (KR cps-) is strongly attenuated and that mice infected with a high dose of KR cps- are still able to induce Mikulicz cells formation, unlike a K. pneumoniae capsule mutant, and to partially recapitulate the characteristic strong production of IL-10. Altogether, the results of this study show that CPS is a virulence factor of K. Rhinoscleromatis not involved in the specific appearance of Mikulicz cells.
Sylvain Brisse - One of the best experts on this subject based on the ideXlab platform.
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Rhinoscleroma pathogenesis the type k3 capsule of klebsiella Rhinoscleromatis is a virulence factor not involved in mikulicz cells formation
PLOS Neglected Tropical Diseases, 2018Co-Authors: Barbara Corelli, Ana S Almeida, Fabiane Sonego, Virginia Castiglia, Cindy Fevre, Sylvain Brisse, Philippe J SansonettiAbstract:Rhinoscleroma is a human specific chronic granulomatous infection of the nose and upper airways caused by the Gram-negative bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. Although considered a rare disease, it is endemic in low-income countries where hygienic conditions are poor. A hallmark of this pathology is the appearance of atypical foamy monocytes called Mikulicz cells. However, the pathogenesis of Rhinoscleroma remains poorly investigated. Capsule polysaccharide (CPS) is a prominent virulence factor in bacteria. All K. Rhinoscleromatis strains are of K3 serotype, suggesting that CPS can be an important driver of Rhinoscleroma disease. In this study, we describe the creation of the first mutant of K. Rhinoscleromatis, inactivated in its capsule export machinery. Using a murine model recapitulating the formation of Mikulicz cells in lungs, we observed that a K. Rhinoscleromatis CPS mutant (KR cps-) is strongly attenuated and that mice infected with a high dose of KR cps- are still able to induce Mikulicz cells formation, unlike a K. pneumoniae capsule mutant, and to partially recapitulate the characteristic strong production of IL-10. Altogether, the results of this study show that CPS is a virulence factor of K. Rhinoscleromatis not involved in the specific appearance of Mikulicz cells.
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A novel murine model of Rhinoscleroma identifies Mikulicz cells, the disease signature, as IL-10 dependent derivatives of inflammatory monocytes.
EMBO Molecular Medicine, 2013Co-Authors: Cindy Fevre, Ana S Almeida, Sylvain Brisse, Solenne Taront, Thierry Pedron, Michel Huerre, Marie-christine Prevost, Aurélie Kieusseian, Ana Cumano, Philippe SansonettiAbstract:Rhinoscleroma is a human specific chronic disease characterized by the formation of granuloma in the airways, caused by the bacterium Klebsiella pneumoniae subspecies Rhinoscleromatis, a species very closely related to K. pneumoniae subspecies pneumoniae. It is characterized by the appearance of specific foamy macrophages called Mikulicz cells. However, very little is known about the pathophysiological processes underlying Rhinoscleroma. Herein, we characterized a murine model recapitulating the formation of Mikulicz cells in lungs and identified them as atypical inflammatory monocytes specifically recruited from the bone marrow upon K. Rhinoscleromatis infection in a CCR2-independent manner. While K. pneumoniae and K. Rhinoscleromatis infections induced a classical inflammatory reaction, K. Rhinoscleromatis infection was characterized by a strong production of IL-10 concomitant to the appearance of Mikulicz cells. Strikingly, in the absence of IL-10, very few Mikulicz cells were observed, confirming a crucial role of IL-10 in the establishment of a proper environment leading to the maturation of these atypical monocytes. This is the first characterization of the environment leading to Mikulicz cells maturation and their identification as inflammatory monocytes.
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PCR-based identification of Klebsiella pneumoniae subsp. Rhinoscleromatis, the agent of Rhinoscleroma.
PLoS Neglected Tropical Diseases, 2011Co-Authors: Cindy Fevre, Virginie Passet, Alexis Deletoile, Valérie Barbe, Lionel Frangeul, Ana Almeida, Philippe Sansonetti, Régis Tournebize, Sylvain BrisseAbstract:Rhinoscleroma is a chronic granulomatous infection of the upper airways caused by the bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. The disease is endemic in tropical and subtropical areas, but its diagnosis remains difficult. As a consequence, and despite available antibiotherapy, some patients evolve advanced stages that can lead to disfiguration, severe respiratory impairment and death by anoxia. Because identification of the etiologic agent is crucial for the definitive diagnosis of the disease, the aim of this study was to develop two simple PCR assays. We took advantage of the fact that all Klebsiella pneumoniae subsp. Rhinoscleromatis isolates are (i) of capsular serotype K3; and (ii) belong to a single clone with diagnostic single nucleotide polymorphisms (SNP). The complete sequence of the genomic region comprising the capsular polysaccharide synthesis (cps) gene cluster was determined. Putative functions of the 21 genes identified were consistent with the structure of the K3 antigen. The K3-specific sequence of gene Kr11509 (wzy) was exploited to set up a PCR test, which was positive for 40 K3 strains but negative when assayed on the 76 other Klebsiella capsular types. Further, to discriminate Klebsiella pneumoniae subsp. Rhinoscleromatis from other K3 Klebsiella strains, a specific PCR assay was developed based on diagnostic SNPs in the phosphate porin gene phoE. This work provides rapid and simple molecular tools to confirm the diagnostic of Rhinoscleroma, which should improve patient care as well as knowledge on the prevalence and epidemiology of Rhinoscleroma.
Cindy Fevre - One of the best experts on this subject based on the ideXlab platform.
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Rhinoscleroma pathogenesis the type k3 capsule of klebsiella Rhinoscleromatis is a virulence factor not involved in mikulicz cells formation
PLOS Neglected Tropical Diseases, 2018Co-Authors: Barbara Corelli, Ana S Almeida, Fabiane Sonego, Virginia Castiglia, Cindy Fevre, Sylvain Brisse, Philippe J SansonettiAbstract:Rhinoscleroma is a human specific chronic granulomatous infection of the nose and upper airways caused by the Gram-negative bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. Although considered a rare disease, it is endemic in low-income countries where hygienic conditions are poor. A hallmark of this pathology is the appearance of atypical foamy monocytes called Mikulicz cells. However, the pathogenesis of Rhinoscleroma remains poorly investigated. Capsule polysaccharide (CPS) is a prominent virulence factor in bacteria. All K. Rhinoscleromatis strains are of K3 serotype, suggesting that CPS can be an important driver of Rhinoscleroma disease. In this study, we describe the creation of the first mutant of K. Rhinoscleromatis, inactivated in its capsule export machinery. Using a murine model recapitulating the formation of Mikulicz cells in lungs, we observed that a K. Rhinoscleromatis CPS mutant (KR cps-) is strongly attenuated and that mice infected with a high dose of KR cps- are still able to induce Mikulicz cells formation, unlike a K. pneumoniae capsule mutant, and to partially recapitulate the characteristic strong production of IL-10. Altogether, the results of this study show that CPS is a virulence factor of K. Rhinoscleromatis not involved in the specific appearance of Mikulicz cells.
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A novel murine model of Rhinoscleroma identifies Mikulicz cells, the disease signature, as IL-10 dependent derivatives of inflammatory monocytes.
EMBO Molecular Medicine, 2013Co-Authors: Cindy Fevre, Ana S Almeida, Sylvain Brisse, Solenne Taront, Thierry Pedron, Michel Huerre, Marie-christine Prevost, Aurélie Kieusseian, Ana Cumano, Philippe SansonettiAbstract:Rhinoscleroma is a human specific chronic disease characterized by the formation of granuloma in the airways, caused by the bacterium Klebsiella pneumoniae subspecies Rhinoscleromatis, a species very closely related to K. pneumoniae subspecies pneumoniae. It is characterized by the appearance of specific foamy macrophages called Mikulicz cells. However, very little is known about the pathophysiological processes underlying Rhinoscleroma. Herein, we characterized a murine model recapitulating the formation of Mikulicz cells in lungs and identified them as atypical inflammatory monocytes specifically recruited from the bone marrow upon K. Rhinoscleromatis infection in a CCR2-independent manner. While K. pneumoniae and K. Rhinoscleromatis infections induced a classical inflammatory reaction, K. Rhinoscleromatis infection was characterized by a strong production of IL-10 concomitant to the appearance of Mikulicz cells. Strikingly, in the absence of IL-10, very few Mikulicz cells were observed, confirming a crucial role of IL-10 in the establishment of a proper environment leading to the maturation of these atypical monocytes. This is the first characterization of the environment leading to Mikulicz cells maturation and their identification as inflammatory monocytes.
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PCR-based identification of Klebsiella pneumoniae subsp. Rhinoscleromatis, the agent of Rhinoscleroma.
PLoS Neglected Tropical Diseases, 2011Co-Authors: Cindy Fevre, Virginie Passet, Alexis Deletoile, Valérie Barbe, Lionel Frangeul, Ana Almeida, Philippe Sansonetti, Régis Tournebize, Sylvain BrisseAbstract:Rhinoscleroma is a chronic granulomatous infection of the upper airways caused by the bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. The disease is endemic in tropical and subtropical areas, but its diagnosis remains difficult. As a consequence, and despite available antibiotherapy, some patients evolve advanced stages that can lead to disfiguration, severe respiratory impairment and death by anoxia. Because identification of the etiologic agent is crucial for the definitive diagnosis of the disease, the aim of this study was to develop two simple PCR assays. We took advantage of the fact that all Klebsiella pneumoniae subsp. Rhinoscleromatis isolates are (i) of capsular serotype K3; and (ii) belong to a single clone with diagnostic single nucleotide polymorphisms (SNP). The complete sequence of the genomic region comprising the capsular polysaccharide synthesis (cps) gene cluster was determined. Putative functions of the 21 genes identified were consistent with the structure of the K3 antigen. The K3-specific sequence of gene Kr11509 (wzy) was exploited to set up a PCR test, which was positive for 40 K3 strains but negative when assayed on the 76 other Klebsiella capsular types. Further, to discriminate Klebsiella pneumoniae subsp. Rhinoscleromatis from other K3 Klebsiella strains, a specific PCR assay was developed based on diagnostic SNPs in the phosphate porin gene phoE. This work provides rapid and simple molecular tools to confirm the diagnostic of Rhinoscleroma, which should improve patient care as well as knowledge on the prevalence and epidemiology of Rhinoscleroma.
Ann Sullivan Baker - One of the best experts on this subject based on the ideXlab platform.
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Rhinoscleroma treated with ciprofloxacin a case report
Laryngoscope, 1995Co-Authors: Robin K Avery, Salah D Salman, Ann Sullivan BakerAbstract:Rhinoscleroma, a chronic progressive infection of the nose and associated structures caused by Klebsiella Rhinoscleromatis, has posed a therapeutic dilemma since its identification in the late 1800s. Although a number of antibiotics have been found to be effective in this relapsing disorder, the lengthy duration of treatment can lead to problems with adverse effects and compliance, especially with the traditional therapies of streptomycin and tetracycline. We report on a patient with extensive nasal Rhinoscleroma who achieved pathologic and bacteriologic resolution during treatment with oral ciprofloxacin after previous courses of tetracycline and trimethoprim-sulfamethoxazole. Ciprofloxacin may prove to be useful in the therapy of Rhinoscleroma because it is convenient for oral administration, achieves good tissue levels, is concentrated in macrophages, and is generally well tolerated as long-term therapy. As mentioned in a recent review of patients with Rhinoscleroma at the Mayo Clinic, the fluoroquinolones deserve further study as potentially highly effective agents for this uncommon but significant infectious condition.
Ana S Almeida - One of the best experts on this subject based on the ideXlab platform.
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Rhinoscleroma pathogenesis the type k3 capsule of klebsiella Rhinoscleromatis is a virulence factor not involved in mikulicz cells formation
PLOS Neglected Tropical Diseases, 2018Co-Authors: Barbara Corelli, Ana S Almeida, Fabiane Sonego, Virginia Castiglia, Cindy Fevre, Sylvain Brisse, Philippe J SansonettiAbstract:Rhinoscleroma is a human specific chronic granulomatous infection of the nose and upper airways caused by the Gram-negative bacterium Klebsiella pneumoniae subsp. Rhinoscleromatis. Although considered a rare disease, it is endemic in low-income countries where hygienic conditions are poor. A hallmark of this pathology is the appearance of atypical foamy monocytes called Mikulicz cells. However, the pathogenesis of Rhinoscleroma remains poorly investigated. Capsule polysaccharide (CPS) is a prominent virulence factor in bacteria. All K. Rhinoscleromatis strains are of K3 serotype, suggesting that CPS can be an important driver of Rhinoscleroma disease. In this study, we describe the creation of the first mutant of K. Rhinoscleromatis, inactivated in its capsule export machinery. Using a murine model recapitulating the formation of Mikulicz cells in lungs, we observed that a K. Rhinoscleromatis CPS mutant (KR cps-) is strongly attenuated and that mice infected with a high dose of KR cps- are still able to induce Mikulicz cells formation, unlike a K. pneumoniae capsule mutant, and to partially recapitulate the characteristic strong production of IL-10. Altogether, the results of this study show that CPS is a virulence factor of K. Rhinoscleromatis not involved in the specific appearance of Mikulicz cells.
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A novel murine model of Rhinoscleroma identifies Mikulicz cells, the disease signature, as IL-10 dependent derivatives of inflammatory monocytes.
EMBO Molecular Medicine, 2013Co-Authors: Cindy Fevre, Ana S Almeida, Sylvain Brisse, Solenne Taront, Thierry Pedron, Michel Huerre, Marie-christine Prevost, Aurélie Kieusseian, Ana Cumano, Philippe SansonettiAbstract:Rhinoscleroma is a human specific chronic disease characterized by the formation of granuloma in the airways, caused by the bacterium Klebsiella pneumoniae subspecies Rhinoscleromatis, a species very closely related to K. pneumoniae subspecies pneumoniae. It is characterized by the appearance of specific foamy macrophages called Mikulicz cells. However, very little is known about the pathophysiological processes underlying Rhinoscleroma. Herein, we characterized a murine model recapitulating the formation of Mikulicz cells in lungs and identified them as atypical inflammatory monocytes specifically recruited from the bone marrow upon K. Rhinoscleromatis infection in a CCR2-independent manner. While K. pneumoniae and K. Rhinoscleromatis infections induced a classical inflammatory reaction, K. Rhinoscleromatis infection was characterized by a strong production of IL-10 concomitant to the appearance of Mikulicz cells. Strikingly, in the absence of IL-10, very few Mikulicz cells were observed, confirming a crucial role of IL-10 in the establishment of a proper environment leading to the maturation of these atypical monocytes. This is the first characterization of the environment leading to Mikulicz cells maturation and their identification as inflammatory monocytes.