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L Naumann

Publications and source records attributed to L Naumann.

At least 19 recordsLinked to original sources
PubMed2006

Comparative macrorestriction and RFLP analysis of Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis isolates from man, pig, and cattle.

In Germany, tuberculous lesions in slaughtered pigs due to infection with members of the Mycobacterium avium complex are increasingly reported. Contaminated food originating from pig or other livestock is discussed as potential source of human infection. M. avium isolates from man (n=45), pig (n=29), and cattle (n=13) were characterised by restriction fragment length polymorphism (RFLP) with respect to insertion sequences IS1245 and IS901 as well as by XbaI-based pulsed-field gel electrophoresis (PFGE) and the results were compared by computer cluster correlation analysis, to determine potential sources of infection in man. By PCR, 55% of animal isolates was identified as M. avium subsp. avium, and 45% as M. a. hominissuis. All human isolates belonged to M. a. hominissuis. IS1245-RFLP and PFGE resulted in two distinct main groupings reflecting the two subspecies, and dividing the isolates into several subgroups. Animal isolates of M. a. hominissuis were widely distributed within the subgroups of human isolates. M. a. avium isolates, further discriminated by IS901-RFLP, formed host-associated subgroups for animals. Comparison of RFLP patterns with those of PFGE resulted in different subgroups as well as different pairs of isolates with high similarities. Only two isolates exhibited identical patterns by both methods. In general, results of both methods support the possibility that M. a. hominissuis isolates from livestock represent a source of infection for man, probably by common environmental reservoirs. There was no evidence of human infections caused by M. a. avium in Germany.

Animals↗
PubMed2006

In-medium effects on phase space distributions of antikaons measured in proton-nucleus collisions.

Differential production cross sections of K+/- mesons have been measured in p + C and p + Au collisions at 1.6, 2.5, and 3.5 GeV proton beam energy. At beam energies close to the production threshold, the K- multiplicity is strongly enhanced with respect to proton-proton collisions. According to microscopic transport calculations, this enhancement is caused by two effects: the strangeness exchange reaction NY --> K- NN and an attractive in-medium K- N potential at saturation density.

Journal Article↗
PubMed2005

Observation of different azimuthal emission patterns of K+ and of K- mesons in heavy-ion collisions at 1-2 A GeV.

Azimuthal distributions of pi+, K+, and K- mesons have been measured in Au+Au reactions at 1.5A GeV and Ni+Ni reactions at 1.93 A GeV. In semicentral collisions at midrapidity, pi+ and K+ mesons are emitted preferentially perpendicular to the reaction plane in both collision systems. In contrast for K- mesons in Ni+Ni reactions, an in-plane elliptic flow was observed for the first time at these incident energies.

Journal Article↗
PubMed2003

First evidence for different freeze-out conditions for kaons and antikaons observed in heavy-ion collisions.

Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.

Journal Article↗
PubMed2003

Pericarditis as primary manifestation of Mycobacterium bovis SSP. caprae infection.

A 76-year-old white male presented with progressive malaise, weight loss and dyspnea at rest. Echocardiography revealed a circular pericardial effusion and global hypokinesia. Pericardiocentesis showed a purulent exudate and microbiologic examination revealed Mycobacterium bovis fully sensitive to isoniazid, streptomycin, ethambutol, rifampin, and pyrazinamide. By spoligotyping the isolate could be further differentiated to M. bovis ssp. caprae. Antimycobacterial therapy was initiated but 3 weeks later the patient's circulation and renal function deteriorated and he died with clinical signs of sepsis despite intensive care treatment. Pericarditis is a rare manifestation of tuberculosis and can be fatal even when diagnosed and treated appropriately. In low incidence countries diagnosis is often delayed and even overlooked.

Animals↗
PubMed2001

Evidence for a Soft Nuclear Equation-of-State from Kaon Production in Heavy-Ion Collisions.

The production of pions and kaons has been measured in 197Au+197Au collisions at beam energies from 0.6 to 1.5A GeV with the kaon spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions, whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.

Journal Article↗
PubMed2000

Mycobacterium heckeshornense sp. nov., A new pathogenic slowly growing Mycobacterium sp. Causing cavitary lung disease in an immunocompetent patient.

A pathogenic scotochromogenic Mycobacterium xenopi-like organism was isolated from the lung of an immunocompetent young woman. This pathogen caused severe bilateral cavitary lung disease, making two surgical interventions necessary after years of chronic disease. This case prompted us to characterize this mycobacterium by a polyphasic taxonomic approach. The isolate contained chemotaxonomic markers which were typical for the genus Mycobacterium, i.e., the meso isomer of 2,6-diaminopimelic acid, arabinose, and galactose as diagnostic whole-cell sugars, MK-9(H(2)) as the principal isoprenoid quinone, a mycolic acid pattern of alpha-mycolates, ketomycolates, and wax ester mycolates, unbranched saturated and unsaturated fatty acids plus a significant amount of tuberculostearic acid, and small amounts of a C(20:0) secondary alcohol. On the basis of its unique 16S rRNA and 16S-23S spacer gene sequences, we propose that the isolate should be assigned to a new species, Mycobacterium heckeshornense. This novel species is phylogenetically closely related to M. xenopi. The type strain of M. heckeshornense is strain S369 (DSM 44428(T)). The GenBank accession number of the 16S rRNA gene of M. heckeshornense is AF174290.

Adult↗
PubMed2000

Novel diagnostic algorithm for identification of mycobacteria using genus-specific amplification of the 16S-23S rRNA gene spacer and restriction endonucleases.

A novel genus-specific PCR for mycobacteria with simple identification to the species level by restriction fragment length polymorphism (RFLP) was established using the 16S-23S ribosomal RNA gene (rDNA) spacer as a target. Panspecificity of primers was demonstrated on the genus level by testing 811 bacterial strains (122 species in 37 genera from 286 reference strains and 525 clinical isolates). All mycobacterial isolates (678 strains among 48 defined species and 5 indeterminate taxons) were amplified by the new primers. Among nonmycobacterial isolates, only Gordonia terrae was amplified. The RFLP scheme devised involves estimation of variable PCR product sizes together with HaeIII and CfoI restriction analysis. It yielded 58 HaeIII patterns, of which 49 (84%) were unique on the species level. Hence, HaeIII digestion together with CfoI results was sufficient for correct identification of 39 of 54 mycobacterial taxons and one of three or four of seven RFLP genotypes found in Mycobacterium intracellulare and Mycobacterium kansasii, respectively. Following a clearly laid out diagnostic algorithm, the remaining unidentified organisms fell into five clusters of closely related species (i.e., the Mycobacterium avium complex or Mycobacterium chelonae-Mycobacterium abscessus) that were successfully separated using additional enzymes (TaqI, MspI, DdeI, or AvaII). Thus, next to slowly growing mycobacteria, all rapidly growing species studied, including M. abscessus, M. chelonae, Mycobacterium farcinogenes, Mycobacterium fortuitum, Mycobacterium peregrinum, and Mycobacterium senegalense (with a very high 16S rDNA sequence similarity) were correctly identified. A high intraspecies sequence stability and the good discriminative power of patterns indicate that this method is very suitable for rapid and cost-effective identification of a wide variety of mycobacterial species without the need for sequencing. Phylogenetically, spacer sequence data stand in good agreement with 16S rDNA sequencing results, as was shown by including strains with unsettled taxonomy. Since this approach recognized significant subspecific genotypes while identification of a broad spectrum of mycobacteria rested on identification of one specific RFLP pattern within a species, this method can be used by both reference (or research) and routine laboratories.

Algorithms↗
PubMed1999

Optimal detection and identification of Mycobacterium haemophilum in specimens from pediatric patients with cervical lymphadenopathy.

Acid-fast bacilli from pediatric patients with lymphadenopathy were detected in the BACTEC radiometric system and in MB Redox broth, but not on Löwenstein Jensen medium. PCR amplification identified the isolates as Mycobacterium haemophilum, which has special nutrition requirements (iron supplements) for growth. Suitable culture medium ensures optimal recovery of this microorganism, avoiding underdiagnosis.

Base Sequence↗
PubMed1998

Mycobacterium bohemicum sp. nov., a new slow-growing scotochromogenic mycobacterium.

A new, slow-growing, scotochromogenic mycobacterium was isolated from sputum of a 53-year-old patient with Down's syndrome suffering from tuberculosis. Growth occurred at temperatures between 25 and 40 degrees C with an optimum at 37 degrees C. This strain had surprisingly few enzymic activities (only positive for 68 degrees C heat-stable catalase and weakly positive for urease) and was sensitive to prothionamide, cycloserine, clarithromycin, gentamicin and amikacin but showed resistance to isoniazid, streptomycin, ethambutol, rifampin and ciprofloxacin. These characteristics assign this organism to a novel mycobacterial species characterized by a unique 16S rDNA nucleotide sequence. The name Mycobacterium bohemicum sp. nov. is proposed for this new, slow-growing, scotochromogenic mycobacterium. The type strain is DSM 44277T.

Base Composition↗
PubMed1998

Clinical evaluation of the automated COBAS AMPLICOR MTB assay for testing respiratory and nonrespiratory specimens.

We evaluated the COBAS AMPLICOR PCR system (Roche Diagnostics) for the routine detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. Diagnostic culture, considered as the reference method, was performed with BACTEC, Löwenstein-Jensen, Stonebrink, and Kirchner media. Occasionally MB-Redox, ESP, or MGIT medium was also used. A total of 643 respiratory and 506 nonrespiratory specimens collected from 807 patients were investigated. Of the 95 culture-positive specimens, 80 were COBAS AMPLICOR MTB positive, and of the 1,054 culture-negative specimens, 1,044 were COBAS AMPLICOR MTB negative. After resolving discrepancies by review of the medical history, the overall sensitivity, specificity, and positive and negative predictive values for the COBAS AMPLICOR MTB assay, respectively, were 83.5, 98.8, 86.7, and 98.6% compared to those of diagnostic culture. In smear-positive specimens, the sensitivity of the COBAS AMPLICOR MTB assay was 96%, versus 48% for smear-negative specimens. No significant differences in the test performance between respiratory and nonrespiratory specimens were observed. The overall inhibition rate was less than 2%, excluding stool specimens. The clear advantages of the COBAS AMPLICOR PCR system are standardized procedures and reagents for specimen processing as well as an internal control for reliable monitoring of PCR inhibitors. By simplifying the work flow through a completely automated amplification and amplicon detection procedure, the COBAS AMPLICOR PCR system proved itself as a very useful component for routine diagnostic procedures.

Automation↗
PubMed1998

16S rRNA sequence diversity in Mycobacterium celatum strains caused by presence of two different copies of 16S rRNA gene.

Direct sequencing of the 16S rRNA gene (16S rDNA) of Mycobacterium celatum isolates showed ambiguities, suggesting heterogeneity. Cloned 16S rDNA yielded two copies of the gene, which differed by insertion of a thymine at position 214 and by additional mismatches. Restriction fragment length polymorphism analysis confirmed the presence of two copies of 16S rDNA within the bacterial chromosome.

Base Sequence↗
PubMed1997

Mycobacterium hassiacum sp. nov., a new rapidly growing thermophilic mycobacterium.

A new rapidly growing, scotochromogenic mycobacterium was isolated from urine. This strain is thermophilic (it grows at 65 degrees C), tolerates 5% NaCl, and was unable to utilize any of the sugars tested or citrate or to take up iron. The isolate splits benzamide, urea, nicotinamide, and pyrazinamide and is sensitive to streptomycin, ethambutol, cycloserine, ciprofloxacin, and chlarithromycin but resistant to isoniazid, rifampin, and prothionamide. These characteristics clearly place this organism in a new mycobacterial species, which was confirmed by the unique 16S rRNA nucleotide sequence. The high level of similarity between this rapid grower and Mycobacterium xenopi is surprising. For this new rapidly growing scotochromogenic and thermophilic mycobacterium we propose the name Mycobacterium hassiacum sp. nov.

Bacteriological Techniques↗
PubMed1996

[Molecular biology methods in detection of mycobacteria. Improved and newly developed test systems for the diagnosis of mycobacteria].

In the coming years, the accurate and rapid microbiological detection of mycobacteria will gain in importance, since infections with Mycobacterium tuberculosis and ubiquitous mycobacteria are expected to increase, in particular in immunocompromised persons. In addition to the classical biochemical methods of detection involving the use of the microscope and cultures, molecular biological techniques are already being used today. The present overview therefore discusses the principles of the major methods. These include the use of the major DNA probes, DNA amplification techniques (PCR) with subsequent DNA sequencing for species determination, and RFLP analysis, which is employed to deal with epidemiological problems. Also described is the Bactec method for culturing in a liquid medium which forms the basis of various modern examination techniques.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Avian mycobacteria].

The avian mycobacteria have been identified first in relation to their virulence for hens. But this property was not definitely to correlate with serovars. Furthermore, this heterogenicity was to confirm on molecular level. Therefore it was necessary to introduce a M.avium complex beside true M.avium. M.avium has special relevance to AIDS patients. This fact shows that the reasons for infections by these facultatively pathogenic mycobacteria are more complicated as accepted.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Pilot study for radiometric detection of mycobacteria in lymph nodes altered by tuberculosis in slaughtered animals].

30 lymph nodes with tuberculous changes from slaughter animals were investigated, comparing radiometric and usual cultural methods for presence of mycobacteria. Mycobacteria were isolated with help of radiometric method (BACTEC 460-TB) from 24 lymph nodes ("sensitivity" 96%, "specificity" 83.3%), and with help of usual cultural method from 22 lymph nodes ("sensitivity" 88%, "specificity" 62.5%). The radiometric method is suitable for isolating of mycobacteria in veterinary medicine diagnostic also.

Animals↗