Search

Your search keyword '"Realini L"' showing total 17 results
Start Over Author "Realini L"
17 results on '"Realini L"'

2. Correlation of pncA sequences with pyrazinamide resistance level in BACTECtm for 21 Mycobacterium tuberculosis clinical isolates

Author

Mestdagh, M., Realini, L., Fonteyne, P. A., Rossau, R., Jannes, G., Mijs, W., De Smet, K. A. L., Portaels, F., and Van den Eeckhout, E.

Subjects
Drug resistance, Bacteriology, Mycobacterium tuberculosis, Pyrazinamide
Abstract

Mutations in the pncA gene, encoding pyrazinamidase, are considered the major mechanism of pyrazinamide (PZA) resistance in Mycobacterium tuberculosis, but resistant strains containing the wild-type gene have been described. The correlation of pncA sequence with PZA resistance level was examined for 21 M. tuberculosis clinical isolates. Susceptibility patterns were determined for 100, 300, and 900 microg/ml concentrations of the drug in BACTEC. Insertions and deletions and a substitution in the putative promoter region led to high-level resistance, whereas substitutions within the open reading frame seemed to confer variable levels of resistance. Variable resistance levels and PZase activities were also observed among isolates lacking pncA mutations. The high-level resistance (900 microg/ml) in pncA wild-type isolates highlights the clinical significance of these isolates. These data also suggest that there may still be more than one alternative mechanism leading to PZA resistance in M. tuberculosis isolates.

Published
2000

3. Species-specific Mycobacterium genavense DNA in intestinal tissues of individuals not infected with human immunodeficiency virus.

Author

Dumonceau, Jean-Marc, Fonteyne, Pierre Alain, Realini, L, Van Gossum, André, Van Vooren, Jean-Paul, Portaels, F, Dumonceau, Jean-Marc, Fonteyne, Pierre Alain, Realini, L, Van Gossum, André, Van Vooren, Jean-Paul, and Portaels, F

Abstract

Mycobacterium genavense species-specific DNA was detected in intestinal tissues from two of nine individuals not infected with human immunodeficiency virus. This newly described microorganism is well documented as a causative agent of disseminated infections in AIDS patients. Our results suggest that it may colonize the guts of individuals not infected with human immunodeficiency virus., Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: no.j, info:eu-repo/semantics/published

Published
1995

9. Cervical lymphadenitis caused by a fastidious mycobacterium closely related to Mycobacterium genavense in an apparently immunocompetent woman: diagnosis by culture-free microbiological methods

Author

Bosquée, L, primary, Böttger, E C, additional, De Beenhouwer, H, additional, Fonteyne, P A, additional, Hirschel, B, additional, Larsson, L, additional, Meyers, W M, additional, Palomino, J C, additional, Realini, L, additional, and Rigouts, L, additional

Published
1995
Full Text
View/download PDF

12. Microaerophilic Conditions Promote Growth ofMycobacterium genavense

Author

Realini, L., De Ridder, K., Palomino, J.-C., Hirschel, B., and Portaels, F.

Abstract

ABSTRACTOur studies show that microaerophilic conditions promote the growth of Mycobacterium genavensein semisolid medium. The growth of M. genavenseat 2.5 or 5% oxygen was superior to that obtained at 21% oxygen in BACTEC primary cultures (Middlebrook 7H12, pH 6.0, without additives). By using nondecontaminated specimens, it was possible to detect growth with very small inocula (25 bacilli/ml) of 12 different M. genavensestrains (from nude mice) within 6 weeks of incubation under low oxygen tension; conversely, with 21% oxygen, no growth of 8 of 12 (66.7%) M. genavensestrains was detected (growth index, <10). The same beneficial effect of 2.5 or 5% oxygen was observed in primary cultures of a decontaminated clinical specimen. Low oxygen tension (2.5 or 5%) is recommended for the primary isolation ofM. genavense. Microaerophilic cultivation of other atypical mycobacteria, especially slow-growing (e.g., Mycobacterium avium) and difficult-to-grow (e.g., Mycobacterium ulcerans) species, is discussed.

Published
1998
Full Text
View/download PDF

14. Relationship between Pyrazinamide Resistance, Loss of Pyrazinamidase Activity, and Mutations in the pncALocus in Multidrug-Resistant Clinical Isolates of Mycobacterium tuberculosis

Author

Mestdagh, M., Fonteyne, P. A., Realini, L., Rossau, R., Jannes, G., Mijs, W., De Smet, K. A. L., Portaels, F., and Van den Eeckhout, E.

Abstract

ABSTRACTSixty-two Mycobacterium tuberculosisisolates were tested for pyrazinamidase activity, and their pyrazinamide susceptibility was determined by the radiometric method. Sequencing ofpncAgenes in the 23 resistant strains revealed mutations in 16 pyrazinamidase-negative strains, 11 of which had not been previously described. Six isolates containing wild-typepncAmight possess alternative resistance mechanisms.

Published
1999
Full Text
View/download PDF

15. Effect of Oxygen on Growth of Mycobacterium ulceransin the BACTEC System

Author

Palomino, J. C., Obiang, A. M., Realini, L., Meyers, W. M., and Portaels, F.

Abstract

ABSTRACTThe effect of low oxygen concentration on the growth of 15 strains of Mycobacterium ulceranswas evaluated in the BACTEC system. Reduced oxygen tension enhanced the growth of M. ulcerans, suggesting that this organism has a preference for microaerobic environments. Application of this observation may improve rates of isolation of M. ulceransin primary culture from clinical samples and promote isolation of the bacterium from environmental sources.

Published
1998
Full Text
View/download PDF

16. Detection of phospholipase C in nontuberculous mycobacteria and its possible role in hemolytic activity.

Author

Gomez A, Mve-Obiang A, Vray B, Rudnicka W, Shamputa IC, Portaels F, Meyers WM, Fonteyne PA, and Realini L

Subjects
Culture Media, Humans, Mycobacterium Infections microbiology, Nucleic Acid Hybridization, Phospholipase D metabolism, Type C Phospholipases genetics, Hemolysis, Mycobacterium enzymology, Mycobacterium pathogenicity, Type C Phospholipases metabolism
Abstract

Phospholipase C plays a key role in the pathogenesis of several bacterial infections, for example, those caused by Clostridium perfringens and Listeria monocytogenes. Previous studies have reported multiple copies of plc genes homologous to Pseudomonas aeruginosa plcH and plcN genes encoding the hemolytic and nonhemolytic phospholipase C enzymes in the genomes of Mycobacterium tuberculosis, M. marinum, M. bovis, and M. ulcerans. In this study we analyzed the possible relationship between phospholipase C and hemolytic activity in 21 strains of nontuberculous mycobacteria representing nine different species. Detection of phospholipase C enzymatic activity was carried out using thin-layer chromatography to detect diglycerides in the hydrolysates of radiolabeled phosphatidylcholine. DNA sequences of M. kansasii and M. marinum homologous to the genes encoding phospholipase C from M. tuberculosis and M. ulcerans were identified by DNA-DNA hybridization and sequencing. Finally, we developed a direct and simple assay to detect mycobacterial hemolytic activity. This assay is based on a modified blood agar medium that allows the growth and expression of hemolysis of slow-growing mycobacteria. Hemolytic activity was detected in M. avium, M. intracellulare, M. ulcerans, M. marinum, M. tuberculosis, and M. kansasii mycobacteria with phospholipase C activity, but not in M. fortuitum. No hemolytic activity was detected in M. smegmatis, M. gordonae, and M. vaccae. Whether or not phospholipase C enzyme plays a role in the pathogenesis of nontuberculous mycobacterial diseases needs further investigation.

Published
2001
Full Text
View/download PDF

17. Correlation of pncA sequence with pyrazinamide resistance level in BACTEC for 21 mycobacterium tuberculosis clinical isolates.

Author

Mestdagh M, Realini L, Fonteyne PA, Rossau R, Jannes G, Mijs W, DE Smet KA, Portaels F, and Van den Eeckhout E

Subjects
Biomarkers, Drug Resistance, Microbial genetics, Humans, Microbial Sensitivity Tests, Mutation, Mycobacterium tuberculosis enzymology, Mycobacterium tuberculosis genetics, Prodrugs metabolism, Pyrazinamide analogs & derivatives, Pyrazinamide metabolism, Amidohydrolases genetics, Amidohydrolases metabolism, Antitubercular Agents pharmacology, Mycobacterium tuberculosis drug effects, Pyrazinamide pharmacology
Abstract

Mutations in the pncA gene, encoding pyrazinamidase, are considered the major mechanism of pyrazinamide (PZA) resistance in Mycobacterium tuberculosis, but resistant strains containing the wild-type gene have been described. The correlation of pncA sequence with PZA resistance level was examined for 21 M. tuberculosis clinical isolates. Susceptibility patterns were determined for 100, 300, and 900 microg/ml concentrations of the drug in BACTEC. Insertions and deletions and a substitution in the putative promoter region led to high-level resistance, whereas substitutions within the open reading frame seemed to confer variable levels of resistance. Variable resistance levels and PZase activities were also observed among isolates lacking pncA mutations. The high-level resistance (900 microg/ml) in pncA wild-type isolates highlights the clinical significance of these isolates. These data also suggest that there may still be more than one alternative mechanism leading to PZA resistance in M. tuberculosis isolates.

Published
2000
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results