Mycobacterium xenopi
Mycobacterium Infections, Nontuberculous
Mycobacterium
Nontuberculous Mycobacteria
Fatty Alcohols
The cyclization and polymerization of bacterially expressed proteins using modified self-splicing inteins. (1/32)
Mini-inteins derived from Synechocystis sp. (Ssp DnaB intein) and Mycobacterium xenopi (Mxe GyrA intein) that have been modified to cleave peptide bonds at their C and N termini, respectively, were cloned in-frame to the N and C termini of a target protein. Peptide bond cleavage of the modified inteins generated an N-terminal cysteine and a C-terminal thioester on the same protein. These complementary reactive groups underwent intra- or intermolecular condensation to generate circular or polymeric protein species with a new peptide bond at the site of ligation. Three cyclic peptides, BBP, an organ specific localization peptide; RGD, an inhibitor of platelet aggregation; and CDR-H3/C2, which inhibits HIV-1 replication, were isolated using the two-intein system. BBP, RGD, and CDR-H3/C2 had masses of 977.1, 1119.9, and 2098.6 g/mol, respectively, as determined by matrix-assisted laser desorption-time of flight mass spectrometry, which agreed well with the values of 977.2, 1120.3, and 2098.3 g/mol, respectively, predicted for the cyclic species. This system was used to cyclize proteins as large as 395 amino acids. Furthermore, multimers of thioredoxin were formed upon concentration of the reactive species, indicating the potential to form novel biomaterials based on fibrous proteins. (+info)Successful treatment of pulmonary Mycobacterium xenopi infection in a natural killer cell-deficient patient with clarithromycin, rifabutin, and sparfloxacin. (2/32)
Isolation of Mycobacterium xenopi from the respiratory tract may indicate pneumonia, often clinically indistinguishable from tuberculosis. Resistance to the classic antituberculous drugs renders the treatment of these infections problematic. We report on a case of cavernous pneumonia caused by M. xenopi in a 36-year-old male with natural killer cell deficiency but without severe immunodeficiency. He was successfully treated with a novel triple-drug combination comprising clarithromycin, sparfloxacin, and rifabutin. An impressive subsequent regression of pathological pulmonary changes was observed, and mycobacteria could no longer be detected. The therapeutic potential of clarithromycin and sparfloxacin in the treatment of M. xenopi infections is discussed. (+info)Overexpression of Fas/CD95 and Fas-induced apoptosis in a patient with idiopathic CD4+ T lymphocytopenia. (3/32)
The mechanisms of apoptosis have become better understood, in part with the discovery of Fas/CD95. We report the case of a patient characterized by a decreased CD4+ T cell count and an overexpression of Fas/CD95 resulting in apoptosis. A 54-year-old man presented with disseminated Mycobacterium xenopi infection. Analysis showed CD4+ T lymphopenia. Tests for human immunodeficiency virus (HIV) types 1 and 2 were negative. We compared the patient with eight healthy controls and five HIV-infected patients in terms of the expression of Fas/CD95 and Fas-mediated apoptosis of peripheral T lymphocytes. The percent of CD95+ cells in lymphocytes was 98% for the patient, and the mean percent of CD95+ cells in lymphocytes +/- SD for HIV-infected patients and healthy controls was 75% +/- 16% and 36% +/- 26%, respectively. The patient had a high level of spontaneous apoptosis, and apoptotic cells were all identified as being CD4+ T cells. Monoclonal antibodies to CD95 dramatically increased apoptosis of CD4+ T cells exclusively. CD4+ T lymphopenia observed in our patient correlated with an overexpression of Fas together with spontaneous and Fas-induced apoptosis. (+info)Use of BACTEC MGIT 960 for recovery of mycobacteria from clinical specimens: multicenter study. (4/32)
The BACTEC MGIT 960 instrument is a fully automated system that exploits the fluorescence of an oxygen sensor to detect growth of mycobacteria in culture. Its performance was compared to those of the radiometric BACTEC 460 instrument and egg-based Lowenstein-Jensen medium. An identical volume of sample was inoculated in different media, and incubation was carried out for 6 weeks with the automatic systems and for 8 weeks on solid media. A total of 2,567 specimens obtained from 1,631 patients were cultured in parallel. Mycobacteria belonging to nine different taxa were isolated by at least one of the culture systems, with 75% of them being represented by Mycobacterium tuberculosis complex. The best yield was obtained with the BACTEC 460 system, with 201 isolates, in comparison with 190 isolates with the BACTEC MGIT 960 system and 168 isolates with Lowenstein-Jensen medium. A similar but not significant difference was obtained when the most-represented organisms, the M. tuberculosis complex, Mycobacterium xenopi, and the Mycobacterium avium complex, were analyzed separately and when combinations of a solid medium with the BACTEC MGIT 960 system and with the BACTEC 460 system were considered. The shortest times to detection were obtained with the BACTEC MGIT 960 system (13.3 days); 1.5 days earlier than that with the BACTEC 460 system (14.8 days) and 12 days earlier than that with Lowenstein-Jensen medium (25.6 days). The BACTEC MGIT 960 system had a contamination rate of 10.0%, intermediate between those of the radiometric system (3.7%) and the egg-based medium (17.0%). We conclude, therefore, that the BACTEC MGIT 960 system is a fully automated, nonradiometric instrument that is suitable for the detection of growth of tuberculous and other mycobacterial species and that is characterized by detection times that are even shorter than that of the "gold standard," the BACTEC 460 system. The contamination rate was higher than that for the radiometric BACTEC 460 system and needs to be improved. (+info)Mycobacterium xenopi and related organisms isolated from stream waters in Finland and description of Mycobacterium botniense sp. nov. (5/32)
Three scotochromogenic Mycobacterium xenopi-like organisms were isolated from stream waters in Finland. These strains grew at 36-50 degrees C but not at 30 degrees C. One of the three strains was fully compatible with the M. xenopi type strain according to GLC-MS, biochemical tests, and 16S rDNA and 16S-23S rDNA internal transcribed spacer (ITS) sequencing. Two of the strains closely resembled M. xenopi in lipid analyses and biochemical tests, but analysis by GLC-MS verified the presence of two new marker fatty acids (2,4,6,x-tetramethyl-eicosanoic acid and 2,4,6,x,x-pentamethyl-docosanoic acid). The 16S rDNA and ITS region sequences of these two strains differed from those of M. xenopi and other previously described mycobacterial sequences. Therefore, the strains are regarded as new species of slow-growing mycobacteria, for which the name Mycobacterium botniense sp. nov. is proposed. The chemical, physical and microbiological quality of the water reservoirs of M. xenopi and M. botniense are described. As far as is known, this is the first time that M. xenopi has been isolated from natural waters. The strains of M. botniense sp. nov. (E347T and E43) have been deposited in the ATCC as strains 700701T and 700702, respectively. (+info)First randomised trial of treatments for pulmonary disease caused by M avium intracellulare, M malmoense, and M xenopi in HIV negative patients: rifampicin, ethambutol and isoniazid versus rifampicin and ethambutol. (6/32)
BACKGROUND: The treatment of pulmonary disease caused by opportunist mycobacteria is controversial. It is uncertain whether in vitro sensitivity testing predicts clinical response in the way it does for Mycobacterium tuberculosis. The literature suggests that the combination of rifampicin (R) and ethambutol (E) is important whereas isoniazid (H) may not be, but to date there have been no published reports of randomised controlled trials in the treatment of these conditions. The British Thoracic Society has conducted the first such trial, a randomised study of two regimens in HIV negative patients with pulmonary disease caused by M avium intracellulare (MAC), M malmoense, and M xenopi. METHODS: When two positive cultures were confirmed by the Mycobacterium Reference Laboratories for England, Wales and Scotland, the coordinating physician invited the patient's physician to enrol the patient. Patients were also recruited from Scandinavia. Randomisation to 2 years of treatment with RE or REH was performed from lists held in the coordinator's office. Clinical, bacteriological, and radiological progress was monitored at set intervals up to 5 years. RESULTS: From October 1987 to December 1992, 141 physicians entered 223 patients (106 with M malmoense, 75 with MAC, 42 with M xenopi). At entry the RE and REH groups were comparable over a range of demographic and clinical features. For each species there was no significant difference between RE and REH in the number of deaths, but when the three species were combined there were fewer deaths from the mycobacterial disease with RE (1% v 8%, p=0.018, odds ratio 0.10, exact 95% CI 0.00 to 0.76). For M malmoense the failure of treatment/relapse rates did not differ appreciably between the regimens, but for MAC there were fewer failures of treatment/relapses with REH (16% v 41%, p=0.033) With M xenopi there was a non-significant trend in the same direction (5% v 18%, p=0.41) and when all three species were combined there was a significant difference in favour of REH (11% v 22%, p=0.033). There was no correlation between failure of treatment/relapse and in vitro resistance. M xenopi was associated with the greatest mortality (57% at 5 years), MAC was the most difficult to eradicate, and M malmoense had the most favourable outlook (42% known to be alive and cured at 5 years). CONCLUSIONS: The results of susceptibility tests performed by the modal resistance method do not correlate with the patient's response to chemotherapy. RE and REH are tolerated better than previous regimens containing second or third line anti-mycobacterial drugs. Treatment of M malmoense with RE for 2 years is preferable to REH. The addition of H reduces the failure of treatment/relapse rates for MAC and has a tendency to do so also for M xenopi, but there is a suggestion that REH is associated with higher death rates overall. Better regimens are required. (+info)Efficacies of clarithromycin regimens against Mycobacterium xenopi in mice. (7/32)
Mice were infected intravenously with 3.5 x 10(7) CFU of Mycobacterium xenopi and treated with various clarithromycin-containing regimens or left untreated for 4 weeks. All nine of the clarithromycin-containing regimens reduced the CFU counts to the levels below the pretreatment values, indicating that these regimens had a bactericidal effect on M. xenopi in mice. The rifampin-isoniazid-ethambutol regimen was significantly less bactericidal than clarithromycin alone or clarithromycin-containing combined regimens. (+info)Mycobacterium xenopi pulmonary infection in an HIV infected patient under highly active antiretroviral treatment. (8/32)
Highly active antiretroviral therapy (HAART) is responsible for a striking reduction in AIDS related morbidity and mortality by partly restoring immune function. However, HAART can also precipitate the development of clinically apparent opportunistic infections in patients with latent infections. We report a case of an HIV infected patient who developed granulomatous nodular and cavitatory lesions of the lungs due to Mycobacterium xenopi as a manifestation of the immune restoration syndrome. (+info)"Mycobacterium xenopi" is a slow-growing, non-tuberculous mycobacterium (NTM) species that is commonly found in the environment, particularly in water sources such as tap water and natural waterways. It is named after the South African frog (Xenopus laevis) from which it was first isolated.
"Mycobacterium xenopi" can cause pulmonary infections, especially in individuals with pre-existing lung conditions such as chronic obstructive pulmonary disease (COPD), bronchiectasis, or prior tuberculosis infection. The symptoms of "M. xenopi" infection are similar to those of tuberculosis and can include cough, fever, night sweats, fatigue, and weight loss.
Diagnosis of "M. xenopi" infection typically requires the isolation and identification of the organism from clinical specimens such as sputum or bronchoalveolar lavage fluid. Treatment usually involves a combination of antibiotics such as macrolides, rifamycins, and aminoglycosides, and may require prolonged therapy for several months to a year or more.
Nontuberculous Mycobacterium (NTM) infections refer to illnesses caused by a group of bacteria called mycobacteria that do not cause tuberculosis or leprosy. These bacteria are commonly found in the environment, such as in water, soil, and dust. They can be spread through inhalation, ingestion, or contact with contaminated materials.
NTM infections can affect various parts of the body, including the lungs, skin, and soft tissues. Lung infections are the most common form of NTM infection and often occur in people with underlying lung conditions such as chronic obstructive pulmonary disease (COPD) or bronchiectasis. Symptoms of NTM lung infection may include cough, fatigue, weight loss, fever, and night sweats.
Skin and soft tissue infections caused by NTM can occur through direct contact with contaminated water or soil, or through medical procedures such as contaminated injections or catheters. Symptoms of NTM skin and soft tissue infections may include redness, swelling, pain, and drainage.
Diagnosis of NTM infections typically involves a combination of clinical symptoms, imaging studies, and laboratory tests to identify the specific type of mycobacteria causing the infection. Treatment may involve multiple antibiotics for an extended period of time, depending on the severity and location of the infection.
"Mycobacterium" is a genus of gram-positive, aerobic, rod-shaped bacteria that are characterized by their complex cell walls containing large amounts of lipids. This genus includes several species that are significant in human and animal health, most notably Mycobacterium tuberculosis, which causes tuberculosis, and Mycobacterium leprae, which causes leprosy. Other species of Mycobacterium can cause various diseases in humans, including skin and soft tissue infections, lung infections, and disseminated disease in immunocompromised individuals. These bacteria are often resistant to common disinfectants and antibiotics, making them difficult to treat.
Nontuberculous mycobacteria (NTM) are a group of environmental mycobacteria that do not cause tuberculosis or leprosy. They can be found in water, soil, and other natural environments. Some people may become infected with NTM, leading to various diseases depending on the site of infection, such as lung disease (most common), skin and soft tissue infections, lymphadenitis, and disseminated disease.
The clinical significance of NTM isolation is not always clear, as colonization without active infection can occur. Diagnosis typically requires a combination of clinical, radiological, microbiological, and sometimes molecular evidence to confirm the presence of active infection. Treatment usually involves multiple antibiotics for an extended period, depending on the species involved and the severity of disease.
Mycobacterium infections are a group of infectious diseases caused by various species of the Mycobacterium genus, including but not limited to M. tuberculosis (which causes tuberculosis), M. avium complex (which causes pulmonary and disseminated disease, particularly in immunocompromised individuals), M. leprae (which causes leprosy), and M. ulcerans (which causes Buruli ulcer). These bacteria are known for their ability to resist destruction by normal immune responses and many disinfectants due to the presence of a waxy mycolic acid layer in their cell walls.
Infection typically occurs through inhalation, ingestion, or direct contact with contaminated materials. The severity and manifestations of the disease can vary widely depending on the specific Mycobacterium species involved, the route of infection, and the host's immune status. Symptoms may include cough, fever, night sweats, weight loss, fatigue, skin lesions, or lymphadenitis. Diagnosis often requires specialized laboratory tests, such as culture or PCR-based methods, to identify the specific Mycobacterium species involved. Treatment typically involves a combination of antibiotics and may require long-term therapy.
Fatty alcohols, also known as long-chain alcohols or long-chain fatty alcohols, are a type of fatty compound that contains a hydroxyl group (-OH) and a long alkyl chain. They are typically derived from natural sources such as plant and animal fats and oils, and can also be synthetically produced.
Fatty alcohols can vary in chain length, typically containing between 8 and 30 carbon atoms. They are commonly used in a variety of industrial and consumer products, including detergents, emulsifiers, lubricants, and personal care products. In the medical field, fatty alcohols may be used as ingredients in certain medications or topical treatments.
'Mycobacterium tuberculosis' is a species of slow-growing, aerobic, gram-positive bacteria that demonstrates acid-fastness. It is the primary causative agent of tuberculosis (TB) in humans. This bacterium has a complex cell wall rich in lipids, including mycolic acids, which provides a hydrophobic barrier and makes it resistant to many conventional antibiotics. The ability of M. tuberculosis to survive within host macrophages and resist the immune response contributes to its pathogenicity and the difficulty in treating TB infections.
M. tuberculosis is typically transmitted through inhalation of infectious droplets containing the bacteria, which primarily targets the lungs but can spread to other parts of the body (extrapulmonary TB). The infection may result in a spectrum of clinical manifestations, ranging from latent TB infection (LTBI) to active disease. LTBI represents a dormant state where individuals are infected with M. tuberculosis but do not show symptoms and cannot transmit the bacteria. However, they remain at risk of developing active TB throughout their lifetime, especially if their immune system becomes compromised.
Effective prevention and control strategies for TB rely on early detection, treatment, and public health interventions to limit transmission. The current first-line treatments for drug-susceptible TB include a combination of isoniazid, rifampin, ethambutol, and pyrazinamide for at least six months. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of M. tuberculosis present significant challenges in TB control and require more complex treatment regimens.
Mycobacterium xenopi - Wikipedia
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