AIM:To study the bacteriocidal or bacteriostatic role of mast cells during infection with Mycobacterium.METHODS:Mycobacterium marinum(M.marinum)(BAA-535/M strain)was investigated for its ability to grow at a temperatu...AIM:To study the bacteriocidal or bacteriostatic role of mast cells during infection with Mycobacterium.METHODS:Mycobacterium marinum(M.marinum)(BAA-535/M strain)was investigated for its ability to grow at a temperature relevant to the mammalian host.Primary mast cells were differentiated from bone marrows of mice,a human mast cell line(HMC-1)and a human monocytic cell line(Mono Mac6)were maintained in culture.Mice were stimulated by intraperitoneal injection of heat-killed M.marinum to study cytochemically the degranulation of peritoneal mast cells.HMC-1 cells were stimulated with M.marinum to analyse m RNA expression for inflammatory reactant genes,while HMC-1 and primary mouse mast cells were infected with M.marinum to establish in parallel cell viability(lactate dehydrogenase release and cell counts)and viable mycobacterial counts.Flow cytometry was used to assess intracellular presence of fluorescein isothiocyanate labelled M.marinum after trypan blue quenching and to measure the extent of infection-induced apoptosis or necrosis in HMC-1.A GFP expressing recombinant M.marinum strain was used to assess intracellular location by fluorescence microscopy.Light microscopy of osmium tetroxide and Gram Twortstained sections of 0.5 μm and transmission electron microscopy were undertaken as sensitive methods.RESULTS:Since its isolation,M.marinum has adapted to grow at 37 ℃.This study found that M.marinum infects HMC-1 cells and primary murine mast cells,where they survive,replicate,and cause dose dependent cell damage over the analysis period of up to 120 h.Amikacin was an effective aminoglycoside antibiotic to eliminate extracellular or membrane attached M.marinum in order to adequately quantify the intracellular bacterial loads.In vivo,intraperitoneal injection of heat-killed M.marinum led to the release of mast cell granules in mice.HMC-1 cells stimulated with M.marinum showed a biphasic pattern of increased mR NA expression for LL-37 and COX-2/TNF-a during 24 h of stimulation.In HMC-1,M.marinum localised to the cytoplasm whereas in primary mast cells,M.marinum were found in vacuoles.CONCLUSION:The effector role of mast cells in infection with M.marinum can be studied in vitro and in vivo.展开更多
Objective To identify Mycobacterium marinum (M. marinum) inducing misdiagnosis and treatment failure. Methods The lesional specimen of patient with cutaneous M. marinum were cultivated on Lwenstein-Jensen medium. Th...Objective To identify Mycobacterium marinum (M. marinum) inducing misdiagnosis and treatment failure. Methods The lesional specimen of patient with cutaneous M. marinum were cultivated on Lwenstein-Jensen medium. The isolate was identified by biochemical tests and polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the hsp65 gene. Results Smooth and non-pigmented colonies were noted after incubation at 32 ℃ for 2 weeks. The isolate was acid-fast bacilli and confirmed as M. marinum by biochemical tests and PCR-RFLP. Conclusion For a correct diagnosis of cutaneous M. marinum infection, it is crucial for clinicians to have a high index of suspicion, obtain the history of exposure and trauma and understand growth characteristics of the organism. Compared with conventional biochemical techniques, PCR-RFLP analysis is a more rapid, accurate and reliable method for mycobacterial identification to species level.展开更多
Treatment of latent tuberculosis infection remains an important goal of global TB eradication.To this end,targets that are essential for intracellular survival of Mycobacterium tuberculosis are particularly attractive...Treatment of latent tuberculosis infection remains an important goal of global TB eradication.To this end,targets that are essential for intracellular survival of Mycobacterium tuberculosis are particularly attractive.Arylamine N-acetyltransferase(NAT)represents such a target as it is,along with the enzymes encoded by the associated gene cluster,essential for mycobacterial survival inside macrophages and involved in cholesterol degradation.Cholesterol is likely to be the fuel for M.tuberculosis inside macrophages.Deleting the nat gene and inhibiting the NAT enzyme prevents survival of the microorganism in macrophages and induces cell wall alterations,rendering the mycobacterium sensitive to antibiotics to which it is normally resistant.To date,NAT from M.marinum(MMNAT)is considered the best available model for NAT from M.tuberculosis(TBNAT).The enzyme catalyses the acetylation and propionylation of arylamines and hydrazines.Hydralazine is a good acetyl and propionyl acceptor for both MMNAT and TBNAT.The MMNAT structure has been solved to 2.1Åresolution following crystallisation in the presence of hydralazine and is compared to available NAT structures.From the mode of ligand binding,features of the binding pocket can be identified,which point to a novel mechanism for the acetylation reaction that results in a 3-methyltriazolo[3,4-a]phthalazine ring compound as product.展开更多
There have been several reports of tuberculosis (TB) and, less frequently, of nontuberculous mycobacterial (NTM) infections in association with tumor necrosis factor α inhibitor (anti-TNFα) therapy. Mycobacterium ma...There have been several reports of tuberculosis (TB) and, less frequently, of nontuberculous mycobacterial (NTM) infections in association with tumor necrosis factor α inhibitor (anti-TNFα) therapy. Mycobacterium marinum is a NTM with a distinct epidemiology and is infrequently responsible for disease in humans. Most commonly, it causes localized skin infections, but in 20% to 40% of cases, it involves deeper structures. Disseminated disease is exceptional and has been reported to occur only in immunocompromised patients. The authors report a clinical case of tenosynovitis and sporotrichoid disease due to M. marinum in a 45-year-old male patient under anti-TNFα therapies for spondyloarthropathy. Along antimicrobial therapy, the patient underwent surgical debridement and after two years he is still on treatment but substantially improved. A few cases of M. marinum infection occurring in patients treated with anti-TNFα drugs have been reported. The diagnosis of infection due to M. marinum requires a high index of suspicion from a properly obtained exposure history and is important so that efficient diagnostic approach and treatment are ensured.展开更多
报告1例游泳池肉芽肿,患者有螃蟹钳伤史。右手背部、前臂出现暗红色丘疹、结节和斑块成线状排列。结核菌纯蛋白衍生物(PPD)(++),皮损组织病理学检查抗酸染色(+),PCR检测分枝杆菌65 kU hsp基因阳性,按照游泳池肉芽肿治疗有效。该病近年...报告1例游泳池肉芽肿,患者有螃蟹钳伤史。右手背部、前臂出现暗红色丘疹、结节和斑块成线状排列。结核菌纯蛋白衍生物(PPD)(++),皮损组织病理学检查抗酸染色(+),PCR检测分枝杆菌65 kU hsp基因阳性,按照游泳池肉芽肿治疗有效。该病近年来呈现增多趋势,患者多为免疫力低下者,多有鱼类接触史。临床上推荐运用临床表现、细菌学检查、组织病理学检查、PCR检测分枝杆菌基因等方法相结合考虑诊断游泳池肉芽肿。国内外曾有将该病误诊为孢子丝菌病、利什曼原虫病的相关报道。该病呈慢性经过,磺胺类药物以及利福平、乙胺丁醇都有明显的临床疗效,克拉霉素和乙胺丁醇对危重患者疗效明显。展开更多
基金Supported by Faculty for the Future Fellowship grant by the Schlumberger Foundation(recipient Siad S)
文摘AIM:To study the bacteriocidal or bacteriostatic role of mast cells during infection with Mycobacterium.METHODS:Mycobacterium marinum(M.marinum)(BAA-535/M strain)was investigated for its ability to grow at a temperature relevant to the mammalian host.Primary mast cells were differentiated from bone marrows of mice,a human mast cell line(HMC-1)and a human monocytic cell line(Mono Mac6)were maintained in culture.Mice were stimulated by intraperitoneal injection of heat-killed M.marinum to study cytochemically the degranulation of peritoneal mast cells.HMC-1 cells were stimulated with M.marinum to analyse m RNA expression for inflammatory reactant genes,while HMC-1 and primary mouse mast cells were infected with M.marinum to establish in parallel cell viability(lactate dehydrogenase release and cell counts)and viable mycobacterial counts.Flow cytometry was used to assess intracellular presence of fluorescein isothiocyanate labelled M.marinum after trypan blue quenching and to measure the extent of infection-induced apoptosis or necrosis in HMC-1.A GFP expressing recombinant M.marinum strain was used to assess intracellular location by fluorescence microscopy.Light microscopy of osmium tetroxide and Gram Twortstained sections of 0.5 μm and transmission electron microscopy were undertaken as sensitive methods.RESULTS:Since its isolation,M.marinum has adapted to grow at 37 ℃.This study found that M.marinum infects HMC-1 cells and primary murine mast cells,where they survive,replicate,and cause dose dependent cell damage over the analysis period of up to 120 h.Amikacin was an effective aminoglycoside antibiotic to eliminate extracellular or membrane attached M.marinum in order to adequately quantify the intracellular bacterial loads.In vivo,intraperitoneal injection of heat-killed M.marinum led to the release of mast cell granules in mice.HMC-1 cells stimulated with M.marinum showed a biphasic pattern of increased mR NA expression for LL-37 and COX-2/TNF-a during 24 h of stimulation.In HMC-1,M.marinum localised to the cytoplasm whereas in primary mast cells,M.marinum were found in vacuoles.CONCLUSION:The effector role of mast cells in infection with M.marinum can be studied in vitro and in vivo.
文摘Objective To identify Mycobacterium marinum (M. marinum) inducing misdiagnosis and treatment failure. Methods The lesional specimen of patient with cutaneous M. marinum were cultivated on Lwenstein-Jensen medium. The isolate was identified by biochemical tests and polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the hsp65 gene. Results Smooth and non-pigmented colonies were noted after incubation at 32 ℃ for 2 weeks. The isolate was acid-fast bacilli and confirmed as M. marinum by biochemical tests and PCR-RFLP. Conclusion For a correct diagnosis of cutaneous M. marinum infection, it is crucial for clinicians to have a high index of suspicion, obtain the history of exposure and trauma and understand growth characteristics of the organism. Compared with conventional biochemical techniques, PCR-RFLP analysis is a more rapid, accurate and reliable method for mycobacterial identification to species level.
文摘Treatment of latent tuberculosis infection remains an important goal of global TB eradication.To this end,targets that are essential for intracellular survival of Mycobacterium tuberculosis are particularly attractive.Arylamine N-acetyltransferase(NAT)represents such a target as it is,along with the enzymes encoded by the associated gene cluster,essential for mycobacterial survival inside macrophages and involved in cholesterol degradation.Cholesterol is likely to be the fuel for M.tuberculosis inside macrophages.Deleting the nat gene and inhibiting the NAT enzyme prevents survival of the microorganism in macrophages and induces cell wall alterations,rendering the mycobacterium sensitive to antibiotics to which it is normally resistant.To date,NAT from M.marinum(MMNAT)is considered the best available model for NAT from M.tuberculosis(TBNAT).The enzyme catalyses the acetylation and propionylation of arylamines and hydrazines.Hydralazine is a good acetyl and propionyl acceptor for both MMNAT and TBNAT.The MMNAT structure has been solved to 2.1Åresolution following crystallisation in the presence of hydralazine and is compared to available NAT structures.From the mode of ligand binding,features of the binding pocket can be identified,which point to a novel mechanism for the acetylation reaction that results in a 3-methyltriazolo[3,4-a]phthalazine ring compound as product.
文摘There have been several reports of tuberculosis (TB) and, less frequently, of nontuberculous mycobacterial (NTM) infections in association with tumor necrosis factor α inhibitor (anti-TNFα) therapy. Mycobacterium marinum is a NTM with a distinct epidemiology and is infrequently responsible for disease in humans. Most commonly, it causes localized skin infections, but in 20% to 40% of cases, it involves deeper structures. Disseminated disease is exceptional and has been reported to occur only in immunocompromised patients. The authors report a clinical case of tenosynovitis and sporotrichoid disease due to M. marinum in a 45-year-old male patient under anti-TNFα therapies for spondyloarthropathy. Along antimicrobial therapy, the patient underwent surgical debridement and after two years he is still on treatment but substantially improved. A few cases of M. marinum infection occurring in patients treated with anti-TNFα drugs have been reported. The diagnosis of infection due to M. marinum requires a high index of suspicion from a properly obtained exposure history and is important so that efficient diagnostic approach and treatment are ensured.
文摘报告1例游泳池肉芽肿,患者有螃蟹钳伤史。右手背部、前臂出现暗红色丘疹、结节和斑块成线状排列。结核菌纯蛋白衍生物(PPD)(++),皮损组织病理学检查抗酸染色(+),PCR检测分枝杆菌65 kU hsp基因阳性,按照游泳池肉芽肿治疗有效。该病近年来呈现增多趋势,患者多为免疫力低下者,多有鱼类接触史。临床上推荐运用临床表现、细菌学检查、组织病理学检查、PCR检测分枝杆菌基因等方法相结合考虑诊断游泳池肉芽肿。国内外曾有将该病误诊为孢子丝菌病、利什曼原虫病的相关报道。该病呈慢性经过,磺胺类药物以及利福平、乙胺丁醇都有明显的临床疗效,克拉霉素和乙胺丁醇对危重患者疗效明显。
