The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform

Johan W. Mouton - One of the best experts on this subject based on the ideXlab platform.

  • Time–kill kinetics of Slowly Growing Mycobacteria common in pulmonary disease
    The Journal of antimicrobial chemotherapy, 2015
    Co-Authors: Beatriz E. Ferro, Jakko Van Ingen, Melanie Wattenberg, Dick Van Soolingen, Johan W. Mouton
    Abstract:

    OBJECTIVES This study aimed to provide basic pharmacodynamic information for key antibiotics used to treat Mycobacterium avium and Mycobacterium xenopi pulmonary disease. METHODS M. avium subspecies hominissuis IWGMT49 and M. xenopi ATCC 19250 type strains were used; the MICs of clarithromycin, amikacin and moxifloxacin were determined by broth microdilution. Time-kill assays were performed, exposing bacteria to 2-fold concentrations from 0.062× to 32× the MIC at 37°C for 240 h for M. avium or 42 days for M. xenopi. The sigmoid maximum effect (Emax) model was fitted to the time-kill curve data. RESULTS Maximum killing of M. avium by amikacin was obtained between 24 and 120 h (0.0180 h(-1)) and was faster and higher than with clarithromycin (0.0109 h(-1)); however, regrowth and amikacin-resistant mutants were observed. Killing rates for M. xenopi were higher, 0.1533 h(-1) for clarithromycin and 0.1385 h(-1) for moxifloxacin, yet required 42 days. There were no significant differences between the Hill's slopes determined for all of the antibiotics tested against M. avium or M. xenopi (P = 0.9663 and P = 0.0844, respectively). CONCLUSIONS The killing effect of amikacin and clarithromycin on M. avium subspecies hominissuis was low, although amikacin activity was higher than that of clarithromycin, supporting its role in a combined therapy. Clarithromycin and moxifloxacin may have similar activity within treatment regimens for M. xenopi disease. Future studies of in vitro and in vivo pharmacokinetic/pharmacodynamic interactions are needed to improve the current regimens to treat these two important Slowly Growing Mycobacteria in pulmonary disease.

  • time kill kinetics of Slowly Growing Mycobacteria common in pulmonary disease
    Journal of Antimicrobial Chemotherapy, 2015
    Co-Authors: Beatriz E. Ferro, Jakko Van Ingen, Melanie Wattenberg, Dick Van Soolingen, Johan W. Mouton
    Abstract:

    OBJECTIVES This study aimed to provide basic pharmacodynamic information for key antibiotics used to treat Mycobacterium avium and Mycobacterium xenopi pulmonary disease. METHODS M. avium subspecies hominissuis IWGMT49 and M. xenopi ATCC 19250 type strains were used; the MICs of clarithromycin, amikacin and moxifloxacin were determined by broth microdilution. Time-kill assays were performed, exposing bacteria to 2-fold concentrations from 0.062× to 32× the MIC at 37°C for 240 h for M. avium or 42 days for M. xenopi. The sigmoid maximum effect (Emax) model was fitted to the time-kill curve data. RESULTS Maximum killing of M. avium by amikacin was obtained between 24 and 120 h (0.0180 h(-1)) and was faster and higher than with clarithromycin (0.0109 h(-1)); however, regrowth and amikacin-resistant mutants were observed. Killing rates for M. xenopi were higher, 0.1533 h(-1) for clarithromycin and 0.1385 h(-1) for moxifloxacin, yet required 42 days. There were no significant differences between the Hill's slopes determined for all of the antibiotics tested against M. avium or M. xenopi (P = 0.9663 and P = 0.0844, respectively). CONCLUSIONS The killing effect of amikacin and clarithromycin on M. avium subspecies hominissuis was low, although amikacin activity was higher than that of clarithromycin, supporting its role in a combined therapy. Clarithromycin and moxifloxacin may have similar activity within treatment regimens for M. xenopi disease. Future studies of in vitro and in vivo pharmacokinetic/pharmacodynamic interactions are needed to improve the current regimens to treat these two important Slowly Growing Mycobacteria in pulmonary disease.

Beatriz E. Ferro - One of the best experts on this subject based on the ideXlab platform.

  • Time–kill kinetics of Slowly Growing Mycobacteria common in pulmonary disease
    The Journal of antimicrobial chemotherapy, 2015
    Co-Authors: Beatriz E. Ferro, Jakko Van Ingen, Melanie Wattenberg, Dick Van Soolingen, Johan W. Mouton
    Abstract:

    OBJECTIVES This study aimed to provide basic pharmacodynamic information for key antibiotics used to treat Mycobacterium avium and Mycobacterium xenopi pulmonary disease. METHODS M. avium subspecies hominissuis IWGMT49 and M. xenopi ATCC 19250 type strains were used; the MICs of clarithromycin, amikacin and moxifloxacin were determined by broth microdilution. Time-kill assays were performed, exposing bacteria to 2-fold concentrations from 0.062× to 32× the MIC at 37°C for 240 h for M. avium or 42 days for M. xenopi. The sigmoid maximum effect (Emax) model was fitted to the time-kill curve data. RESULTS Maximum killing of M. avium by amikacin was obtained between 24 and 120 h (0.0180 h(-1)) and was faster and higher than with clarithromycin (0.0109 h(-1)); however, regrowth and amikacin-resistant mutants were observed. Killing rates for M. xenopi were higher, 0.1533 h(-1) for clarithromycin and 0.1385 h(-1) for moxifloxacin, yet required 42 days. There were no significant differences between the Hill's slopes determined for all of the antibiotics tested against M. avium or M. xenopi (P = 0.9663 and P = 0.0844, respectively). CONCLUSIONS The killing effect of amikacin and clarithromycin on M. avium subspecies hominissuis was low, although amikacin activity was higher than that of clarithromycin, supporting its role in a combined therapy. Clarithromycin and moxifloxacin may have similar activity within treatment regimens for M. xenopi disease. Future studies of in vitro and in vivo pharmacokinetic/pharmacodynamic interactions are needed to improve the current regimens to treat these two important Slowly Growing Mycobacteria in pulmonary disease.

  • time kill kinetics of Slowly Growing Mycobacteria common in pulmonary disease
    Journal of Antimicrobial Chemotherapy, 2015
    Co-Authors: Beatriz E. Ferro, Jakko Van Ingen, Melanie Wattenberg, Dick Van Soolingen, Johan W. Mouton
    Abstract:

    OBJECTIVES This study aimed to provide basic pharmacodynamic information for key antibiotics used to treat Mycobacterium avium and Mycobacterium xenopi pulmonary disease. METHODS M. avium subspecies hominissuis IWGMT49 and M. xenopi ATCC 19250 type strains were used; the MICs of clarithromycin, amikacin and moxifloxacin were determined by broth microdilution. Time-kill assays were performed, exposing bacteria to 2-fold concentrations from 0.062× to 32× the MIC at 37°C for 240 h for M. avium or 42 days for M. xenopi. The sigmoid maximum effect (Emax) model was fitted to the time-kill curve data. RESULTS Maximum killing of M. avium by amikacin was obtained between 24 and 120 h (0.0180 h(-1)) and was faster and higher than with clarithromycin (0.0109 h(-1)); however, regrowth and amikacin-resistant mutants were observed. Killing rates for M. xenopi were higher, 0.1533 h(-1) for clarithromycin and 0.1385 h(-1) for moxifloxacin, yet required 42 days. There were no significant differences between the Hill's slopes determined for all of the antibiotics tested against M. avium or M. xenopi (P = 0.9663 and P = 0.0844, respectively). CONCLUSIONS The killing effect of amikacin and clarithromycin on M. avium subspecies hominissuis was low, although amikacin activity was higher than that of clarithromycin, supporting its role in a combined therapy. Clarithromycin and moxifloxacin may have similar activity within treatment regimens for M. xenopi disease. Future studies of in vitro and in vivo pharmacokinetic/pharmacodynamic interactions are needed to improve the current regimens to treat these two important Slowly Growing Mycobacteria in pulmonary disease.

Michel Drancourt - One of the best experts on this subject based on the ideXlab platform.

  • Mycobacterium terramassiliense, Mycobacterium rhizamassiliense and Mycobacterium numidiamassiliense sp. nov., three new Mycobacterium simiae complex species cultured from plant roots
    Scientific Reports, 2018
    Co-Authors: A. Bouam, N. Armstrong, A. Levasseur, Michel Drancourt
    Abstract:

    Three Slowly Growing Mycobacteria named strain AB308, strain AB215 and strain AB57 were isolated from the tomato plant roots. The 16S rRNA and rpoB gene sequence analyses suggested that each strain was representative of one hitherto unidentified Slowly-Growing Mycobacterium species of the Mycobacterium simiae complex. Genome sequencing indicated that each strain contained one chromosome of 6.015–6.029 Mbp. A total of 1,197, 1,239 and 1,175 proteins were found to be associated with virulence and 107, 76 and 82 proteins were associated with toxin/antitoxin systems for strains AB308, AB215 and AB57, respectively. The three genomes encode for secondary metabolites, with 38, 33 and 46 genes found to be associated with polyketide synthases/non-ribosomal peptide synthases and nine, seven and ten genes encoding for bacteriocins, respectively. The genome of strain AB308 encodes for one questionable prophage and three incomplete prophages, while only incomplete prophages were predicted in AB215 and AB57 genomes. Genetic and genomic data indicate that strains AB308, AB215 and AB57 are each representative of a new Mycobacterium species that we respectively named Mycobacterium terramassiliense , Mycobacterium numidiamassiliense and Mycobacterium rhizamassiliense .

  • rpob sequence based identification of mycobacterium avium complex species
    Microbiology, 2008
    Co-Authors: Iskandar Ben Salah, Toidi Adekambi, Michel Drancourt
    Abstract:

    The Mycobacterium avium complex (MAC) comprises Slowly Growing Mycobacteria responsible for opportunistic infections and zoonoses. The ability to speciate MAC isolates in the clinical microbiology laboratory is critical for determining the organism implicated in clinical disease and for epidemiological investigation of the source of infection. Investigation of a 711 bp variable fragment of rpoB flanked by the Myco-F/Myco-R primers found a 0.7–5.1 % divergence among MAC reference strains, with Mycobacterium chimaera and Mycobacterium intracellulare being the most closely related. Using a 0.7 % divergence cut-off, 83 % of 100 clinical isolates, which had been previously identified by phenotypic characteristics and 16S–23S rDNA intergenic spacer (ITS) probing, were identified as M. avium, 8 % as M. intracellulare and 2 % as M. chimaera. The uniqueness of seven isolates, exhibiting <99.3 % rpoB sequence similarity with MAC reference strains, was confirmed by 16S rDNA, ITS and hsp65 sequencing and phylogenetic analyses. Partial rpoB gene sequencing using the Myco-F/Myco-R primers permits one-step identification of MAC isolates at the species level and the detection of potentially novel MAC species.

Laura C Rodrigues - One of the best experts on this subject based on the ideXlab platform.

  • skin test reactivity to Mycobacterial antigens parallels the phylogenetic structure of their genus
    International Journal of Tuberculosis and Lung Disease, 2001
    Co-Authors: Ana Luiza Bierrenbach, Sergio Souza Da Cunha, Mauricio Lima Barreto, Susan Martins Pereira, Laura C Rodrigues
    Abstract:

    SETTING: City of Manaus, Amazonas, Brazil. OBJECTIVE: To explore the relationship between positivity to tuberculin and other environmental Mycobacteria sensitins, according to a range of criteria and presence of BCG scar. DESIGN: Dual skin testing with tuberculin and four Mycobacterial sensitins, and BCG scar recording of 1070 schoolchildren aged 7-14. Four criteria for positivity were used: simple and dominant, with 5 and 10 mm cut-off points. RESULTS: The standardised prevalence of reactions > or = 5 mm for BCG scar negative children was 58.3% for Mycobacterium avium, 54.2% for M. scrofulaceum, 26.8% for M. fortuitum, 17.9% for M. tuberculosis and 7.6% for M. kansasii. Correlations between tuberculin and each sensitin, for BCG scar negative children, were 0.47 for M. avium, 0.53 for M. scrofulaceum, 0.60 for M. kansasii and 0.22 for M. fortuitum (all with P or = 5 mm, P < 0.001) and influenced the balance between dominant/non-dominant reactions for all sensitins. CONCLUSION: The correlation between tuberculin and each sensitin confirmed the separation of the rapidly (M. fortuitum) and Slowly Growing Mycobacteria (M. tuberculosis, M. avium, M. scrofulaceum and M. kansasii). The influence of BCG on tuberculin reactions was more marked than on other Mycobacterial sensitins.

  • Skin test reactivity to Mycobacterial antigens parallels the phylogenetic structure of their genus.
    The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 2001
    Co-Authors: Ana Luiza Bierrenbach, Sergio Souza Da Cunha, Mauricio Lima Barreto, Susan Martins Pereira, Laura C Rodrigues
    Abstract:

    City of Manaus, Amazonas, Brazil. To explore the relationship between positivity to tuberculin and other environmental Mycobacteria sensitins, according to a range of criteria and presence of BCG scar. Dual skin testing with tuberculin and four Mycobacterial sensitins, and BCG scar recording of 1070 schoolchildren aged 7-14. Four criteria for positivity were used: simple and dominant, with 5 and 10 mm cut-off points. The standardised prevalence of reactions > or = 5 mm for BCG scar negative children was 58.3% for Mycobacterium avium, 54.2% for M. scrofulaceum, 26.8% for M. fortuitum, 17.9% for M. tuberculosis and 7.6% for M. kansasii. Correlations between tuberculin and each sensitin, for BCG scar negative children, were 0.47 for M. avium, 0.53 for M. scrofulaceum, 0.60 for M. kansasii and 0.22 for M. fortuitum (all with P < 0.01). BCG effect was particularly significant for tuberculin (odds ratio = 3.44 for reactions > or = 5 mm, P < 0.001) and influenced the balance between dominant/non-dominant reactions for all sensitins. The correlation between tuberculin and each sensitin confirmed the separation of the rapidly (M. fortuitum) and Slowly Growing Mycobacteria (M. tuberculosis, M. avium, M. scrofulaceum and M. kansasii). The influence of BCG on tuberculin reactions was more marked than on other Mycobacterial sensitins.

Marja-leena Katila - One of the best experts on this subject based on the ideXlab platform.

  • gas chromatographic lipid profiles in identification of currently known Slowly Growing environmental Mycobacteria
    Journal of Medical Microbiology, 2003
    Co-Authors: Pirjo Torkko, Marja-leena Katila, Merja H Kontro
    Abstract:

    Cellular fatty acid analysis by GLC is widely used in the species identification of Mycobacteria. Combining mycolic acid cleavage products with shorter cellular fatty acids increases the informative value of the analysis. A key has been created to aid in the identification of all currently known Slowly Growing environmental species. In this scheme, the species are classified into six categories, each characterized by a combination of fatty markers shared by those species. Within each category, individual species may be distinguished by the presence or absence of specific marker substances, such as methyl-branched fatty acids or secondary alcohols. This study also describes earlier unpublished GLC profiles of 14 rare, Slowly Growing, environmental Mycobacteria, Mycobacterium asiaticum, Mycobacterium botniense, Mycobacterium branderi, Mycobacterium conspicuum, Mycobacterium cookii, Mycobacterium doricum, Mycobacterium heckeshornense, Mycobacterium heidelbergense, Mycobacterium hiberniae, Mycobacterium kubicae, Mycobacterium lentiflavum, Mycobacterium scrofulaceum, Mycobacterium triplex and Mycobacterium tusciae. Though no single identification technique alone, even sequencing of an entire single gene such as 16S rRNA, can identify all Mycobacterial species accurately, GLC has proven to be both reliable and reproducible in the identification of Slowly Growing Mycobacteria. In cases of earlier unknown species, it generates useful information that allows their further classification and may lead to the description of novel species.

  • Slowly Growing Mycobacteria and Chronic Skin Disorders
    Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 1996
    Co-Authors: Jaana Olivia Mattila, Marja-leena Katila, Martine Vornanen
    Abstract:

    We evaluated the role of Mycobacteria in chronic skin manifestations. The etiologies of chronic skin disorders in 90 patients were analyzed by culture, histopathologic examination, and skin testing for Mycobacteria. There were 20 clinical diagnoses; prurigo nodularis was the most common diagnosis (43 patients). Cultures were incubated at 32 degrees C and 36 degrees C for 6 months. Fourteen cultures (16%) yielded the following Mycobacteria: Mycobacterium tuberculosis (5), Mycobacterium avium/Mycobacterium intracellulare complex (3), Mycobacterium malmoense (2), and other Mycobacteria (4). Acid-fast bacilli were detected in 24 (28%) of the 86 histopathologic specimens examined, including nine of the 14 culture-positive specimens. Granulomatous infection was present in three specimens (3%); cultures of two of these specimens yielded M. tuberculosis, and culture of one was negative. Skin reactivity to 12 Mycobacterial antigens was tested. The patients for whom staining and/or culture was positive for Mycobacteria had significantly larger skin reactions to M. malmoense antigen (P < .001) than did the patients with bacteriologically negative skin disorders. There was no correlation between the species isolated and the skin reactivity to the species-specific antigen.

  • Characterization of a distinct group of Slowly Growing Mycobacteria by biochemical tests and lipid analyses.
    Journal of Clinical Microbiology, 1992
    Co-Authors: Erik Brander, Erik Jantzen, A Julkunen, Reetta Huttunen, Marja-leena Katila
    Abstract:

    A group of Slowly Growing Mycobacterial strains (n = 14) isolated from respiratory tract specimens was collected from 1971 to 1990 on the basis of growth characteristics and uncommon biochemical and glycolipid profiles. Growth at 25 to 45 degrees C, a negative Tween 80 hydrolysis test, a strong positive reaction in a 14-day arylsulfatase test, and susceptibility to ethambutol in combination with resistance to cycloserine were important for the initial separation. The strains had a distinctive glycolipid pattern which was unlike those of other Mycobacterial species. Analyses of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography further characterized this homogeneous group of Mycobacteria. The presence of 2-eicosanol (2-OH-20:0alc) and hexacosanoic acid (26:0) combined with the lack of 2-docosanol (2-OH-22:0alc) differentiated this group from other Slowly Growing Mycobacteria. Images

  • Characterization of a distinct group of Slowly Growing Mycobacteria by biochemical tests and lipid analyses.
    Journal of clinical microbiology, 1992
    Co-Authors: Eljas Brander, Erik Jantzen, A Julkunen, Reetta Huttunen, Marja-leena Katila
    Abstract:

    A group of Slowly Growing Mycobacterial strains (n = 14) isolated from respiratory tract specimens was collected from 1971 to 1990 on the basis of growth characteristics and uncommon biochemical and glycolipid profiles. Growth at 25 to 45 degrees C, a negative Tween 80 hydrolysis test, a strong positive reaction in a 14-day arylsulfatase test, and susceptibility to ethambutol in combination with resistance to cycloserine were important for the initial separation. The strains had a distinctive glycolipid pattern which was unlike those of other Mycobacterial species. Analyses of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography further characterized this homogeneous group of Mycobacteria. The presence of 2-eicosanol (2-OH-20:0alc) and hexacosanoic acid (26:0) combined with the lack of 2-docosanol (2-OH-22:0alc) differentiated this group from other Slowly Growing Mycobacteria.