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Biomedical subjects

T Bodmer

Publications and source records attributed to T Bodmer.

At least 19 recordsLinked to original sources
PubMed2005

Development of real-time PCR for the differential detection and quantification of Ureaplasma urealyticum and Ureaplasma parvum.

Ureaplasma parvum and Ureaplasma urealyticum are recently recognized species of the genus Ureaplasma. In humans, Ureaplasma spp. can be found on mucosal surfaces, primarily in the respiratory and urogenital tracts. They have been implicated in various human diseases such as nongonococcal urethritis, intrauterine infections in association with adverse pregnancy outcome and fetal morbidity, and pneumonitis in immunocompromised hosts. We have developed two quantitative real-time PCR assays to differentially detect U. parvum and U. urealyticum. Based upon the sequence information of the urease gene (ureB), we designed two TaqMan primer and probe combinations specific for U. parvum and U. urealyticum, respectively. The assays did not react with nucleic acid preparations from 16 bacterial species commonly encountered in relevant clinical specimens, including seven urease-producing species. Each assay had a detection limit of approximately five copies per reaction of the respective gene target. The results suggest that these assays are both sensitive and specific for U. parvum and U. urealyticum. Further investigation of both assays using clinical specimens is appropriate.

DNA, Bacterial↗
PubMed2004

Failure of ceftriaxone in an intravenous drug user with invasive infection due to Ralstonia pickettii.

We report a case of septic arthritis due to Ralstonia pickettii in an intravenous drug user with unfavorable clinical course under antibiotic therapy with ceftriaxone despite in vitro susceptibility to the drug. The treatment failure may have been due to a discrepancy between in vitro and in vivo susceptibility of R. pickettii, or to resistance development mediated by a recently described inducible beta-lactamase.

Adult↗
PubMed2003

[Nocardia cyriacigeorgici: First report of invasive human infection].

BACKGROUND: Diagnostic laboratories increasingly offer bacterial identification to the species level. The 17 nocardia species known to date differ in their clinical presentation, antibiotic resistance patterns and geographic distribution. The discovery of a new species with pathogenicity for humans calls for the characterization of its clinical and epidemiological properties. PATIENTS AND METHODS: Nocardia isolated from multifocal brain abscesses of an immunocompromised patient were further identified by the analysis of their cellular fatty acids and sequencing of the 16S ribosomal DNA. Quantitative antibiotic resistance testing was performed with E-tests. RESULTS: The 16S ribosomal DNA analysis showed a 99 % homology to Nocardia cyriacigeorgici. This is the first report of this species as an invasive human pathogen. N. cyriacigeorgici was found susceptible for meropenem, amikacin, ceftriaxon and cotrimoxazole. The combination of surgical drainage and antibiotic treatment for 13 months was curative. CONCLUSIONS: N. cyriacigeorgici has the potential to cause invasive infections at least in immunocompromised patients. Comparing clinical and in vitro characteristics with N. asteroides, the main causative agent of nocardial infections in Europe, we found no clinically relevant differences.

Amikacin↗
PubMed2003

Development and application of real-time PCR assay for quantification of Mycobacterium ulcerans DNA.

Buruli ulcer, an infection caused by Mycobacterium ulcerans, is, after tuberculosis and leprosy, the third most common mycobacterial disease. The mode of transmission of M. ulcerans is not exactly known, but since Buruli ulcer often occurs in focalized swampy areas, it is assumed that there is a reservoir of the pathogen in stagnant water. Buruli ulcer usually starts as a painless nodule and can lead to massive destruction of skin, subcutaneous tissue, and eventually muscle and bone. Currently the only recommended treatment is wide surgical excision. In this report we describe the development of a real-time PCR method for the quantification of M. ulcerans DNA (IS2404 TaqMan). The highly specific assay is based on the detection of the M. ulcerans specific insertion sequence IS2404. The IS2404 TaqMan assay turned out to be about 10 times more sensitive than the available conventional PCR-based diagnostic test. It is demonstrated that the IS2404 TaqMan assay is suitable for the quantitative assessment of the dissemination of the mycobacteria in Buruli ulcer lesions. Prototype results obtained with excised tissue from a patient with a late preulcerative Buruli ulcer lesion reconfirmed earlier histopathological findings indicating that tissue damage occurs far beyond the regions in which large numbers of mycobacteria are detectable. The IS2404 TaqMan assay should be a useful tool for both diagnosis and research into the pathology and mode of transmission of this still inadequately investigated mycobacterial disease.

Child↗
PubMed2001

Nocardial brain abscess: observation of treatment strategies and outcome in Switzerland from 1992 to 1999.

BACKGROUND: Brain abscesses caused by Nocardia spp. are rare, but life-threatening infections that are notoriously difficult to diagnose and treat and which occur mainly in immunocompromised patients. Standard treatment guidelines are not available. METHODS: A systematic search for nocardial brain abscesses from 1992 to 1999 was conducted in Switzerland for the comparison of clinical presentation, treatment strategies and outcome. RESULTS: Seven cases were found, for which data of six were available. In 4/6 patients antimicrobial therapy led to a decrease in the size of abscesses. Four of six patients died. The cause of death was likely due to underlying co-morbidities, rather than the nocardial infection. CONCLUSION: The finding that treatment was different in each case underscores the lack of therapeutic guidelines.

Adult↗
PubMed2000

[Clinical presentation and therapy of Mycobacterium marinum infection as seen in 12 cases].

BACKGROUND AND OBJECTIVE: Mycobacterium marinum (M.m.) is the causative pathogen of skin infections that have been called "swimming pool granulomas". An increasing number of reports that deep structures are involved in these infections was the reason for studying the clinical presentation and response of the infection to different therapeutic regimens. PATIENTS AND METHODS: All patients (eight men, four women, age range 18-73 years) were included in whom, between january 1991 and February 1995, M.m. infection had been proven by culture. The clinical data of these patients were retrospectively obtained by standardized questionnaire. RESULTS: The infection was limited to the skin in four of the twelve patients, deep structures only were involved in three, and five had both. Infections limited to the skin were successfully treated with sulphamethoxazole and trimethoprim or with tetracyclines, while rifampicin, alone or in combination with ethambutol, was efficacious when deep structures were involved. No surgical intervention was--or should be--performed. CONCLUSIONS: Infections with M.m. often involve deep structures, even in the absence of the skin being involved. The term "swimming pool granuloma" is, therefore, misleading when the infection is limited to he skin. A history of a chronic and indolent course, frequent changes of doctor and striking polypharmacy in its treatment are pointers to this infection.

Adolescent↗
PubMed2000

Mycobacterium avium resists exposure to the acidic conditions of the stomach.

Organisms of the Mycobacterium avium complex are common pathogens in immunosuppressed patients such as individuals with AIDS. There is evidence that in AIDS patients, the main route for M. avium infection is the gastrointestinal tract. The stomach is a formidable barrier to pathogens and the ability to resist exposure to pH lower than 3 has been shown to be a virulence determinant of enteric pathogens. Incubation of three clinical isolates of M. avium under acidic pH revealed resistance of M. avium grown both to the exponential and stationary phase at pH 2.2 for 2 h. Inhibition of protein synthesis had no effect on the acid tolerance. When the duration of the incubation at pH 2.2 was extended to 24 h, bacteria grown to the stationary phase had a significantly greater tolerance to acid than exponential phase bacteria. M. avium incubated with acid in the presence of water was significantly more resistant to pH 2.2 than M. avium in the presence of buffer. Pre-adaptation in water prior to exposure to acidic conditions was also associated with increased resistance to pH 2.2. Isoosmolarity of Hank's balanced salt solution appears to be responsible for the impaired resistance to acid between 2 and 24 h of incubation. These findings indicate that M. avium is naturally tolerant to pH<3 and that pre-adaptation under conditions similar to the conditions where M. avium is found in the environment results in increased acid resistance.

Adaptation, Physiological↗
PubMed2000

Mycobacterium genavense infection in a patient with long-standing chronic lymphocytic leukaemia.

We describe the first case of disseminated infection with Mycobacterium genavense in an HIV-seronegative patient with a chronic haematological disorder. Our patient, an 80-year-old woman, had been under long-term treatment with chlorambucil (partially in combination with prednisone) for B-cell chronic lymphocytic leukaemia (B-CLL). When she developed general fatigue and progressive anaemia, as well as progressive lymphadenopathy and splenomegaly, bone marrow biopsy revealed granulomas with acid-fast bacilli, and cultures of both bone marrow and blood grew M. genavense. The patient's CD4+ cell count was approximately 100 microL(-1). Treatment with clarithromycin, ethambutol and rifabutin resulted in improvement of anaemia and general health as well as in regression of lymphadenopathy and splenomegaly.

Aged↗
PubMed2000

Characterization of IS666, a newly described insertion element of Mycobacterium avium.

The insertion sequence IS666 was isolated from Mycobacterium avium strain 101. IS666 is a 1474 bp insertion sequence belonging to the IS256 family, that includes IS6120 from Mycobacterium smegmatis, IS1166 and IS1295 from Rhodococcus sp. IGTS8, IST2 from Thiobacillus ferrooxidans, IS256 from Staphylococcus aureus, and ISRm3 from Rhizobium meliloti. IS666 has 24 bp imperfect inverted repeats that fit the consensus described for the family, and generates 9 bp duplications upon insertion into the host DNA with no apparent specificity in the target sequence. In contrast with its two closest homologues, IS1166 and IS6120, IS666 contains a single ORF that would codify a transposase of 434 aa. IS666 is restricted to M. avium, where it is present in 21% of the isolates in a number ranging between 1 to 7 copies.

Amino Acid Sequence↗
PubMed1999

[The prevalence of salmonella, yersinia and mycobacteria in slaughtered pigs in Switzerland].

Clinically healthy food animals can be reservoirs for various foodborne pathogens. In general, such animals do not have lesions that are visible during meat inspection. Pigs are considered to be carriers of salmonella, yersinia and mycobacteria, but the risk of transmission to humans is difficult to assess. The aim of this study was to estimate the actual prevalence of the three above mentioned pathogens in the Swiss pig population and to comment on their significance. A total of 570 samples each of tonsils and mesenteric lymphnodes, were collected at two slaughterhouses from carcasses of apparently healthy pigs and analyzed for the presence of salmonella, yersinia and mycobacteria. The prevalence of salmonella (0.9%) was found to be lower than--while that of yersinia (8.1%) and mycobacteria (12.8%) about equal to--results reported from other European countries. Yersinia typing showed that serotype O:9 of Yersinia enterocolitica (2.5%) was 6 to 7 times more frequent than serotype O:3 (0.4%)--formerly the most frequent serotype. Mycobacterium avium was the most frequent isolate (90.7%) among the mycobacteria isolated. Although all three pathogens are present in the Swiss pig population, we consider the risk of transmission to humans via consumption of pork as low. Appropriate preventive measures and quality management should contribute to keep the risk under control.

Abattoirs↗
PubMed1998

IS1245 restriction fragment length polymorphism typing of Mycobacterium avium isolates: proposal for standardization.

Mycobacterium avium has become a major human pathogen, primarily due to the emergence of the AIDS epidemic. Restriction fragment length polymorphism (RFLP) typing, using insertion sequence IS1245 as a probe, provides a powerful tool in the molecular epidemiology of M. avium-related infections and will facilitate well-founded studies into the sources of M. avium infections in animal and environmental reservoirs. The standardization of this technique allows computerization of IS1245 RFLP patterns for comparison on a local level and the establishment of M. avium DNA fingerprint databases for interlaboratory comparison. Moreover, by combining international DNA typing results of M. avium complex isolates from a broad spectrum of sources, long-lasting questions on the epidemiology of this major agent of mycobacterial infections will be answered.

AIDS-Related Opportunistic Infections↗
PubMed1997

Evaluation of the COBAS AMPLICOR MTB system.

A panel of 1,012 respiratory sediments was retrospectively tested by PCR amplification to detect Mycobacterium tuberculosis with the COBAS AMPLICOR MTB system. The sensitivities and specificities of COBAS and fluorescence microscopy compared to culture were 92.6 versus 95.6% and 99.6 versus 95.3%, respectively. Inhibition occurred in 48 (4.7%) specimens.

Bronchoalveolar Lavage Fluid↗
PubMed1997

[Occurrence of Mycobacterium genavense in birds].

A total of 253 birds were investigated to determine the presence of mycobacteria. Scrapings from various internal organs were stained according to Ziehl-Neelsen, and acid-fast bacilli were found in 26 birds (10.2%). Cultivation of mycobacteria was attempted from 22 livers, 12 spleens, 14 kidneys, 12 lungs, and 9 intestines from these 26 birds. Each sample was first decontaminated using a modified sodium dodecyl sulfate method, and three media were inoculated (Bactec 12 B; Löwenstein-Jensen, Herrold). Using a Polymerase-Chain-Reaction-Restriction-Enzyme-Analysis (PRA), M. genavense could be identified in 19 of 26 birds (73%). M. avium could be isolated from three birds and M. fortuitum from one bird. In total, mycobacteriosis was the primary diagnosis made in 24 of 26 birds (92%). A presumptive diagnosis of mycobacteriosis was already made macroscopically in 14 of these birds. In the remaining 10 cases, bacteriological and histological investigations with specific staining methods were necessary for diagnosis. Several different histological changes were found. We observed individual macrophages as well as epitheloid cell proliferation, with variable, relatively mild inflammatory and fibrous reactions. We could not find any correlation between infection with a mycobacterium species and a specific tissue reaction pattern. This report demonstrates that M. genavense is an important cause of avian mycobacteriosis especially in pet birds.

Animals↗
PubMed1996

Isolation and characterization of a unique group of slowly growing mycobacteria: description of Mycobacterium lentiflavum sp. nov.

A distinct group of slowly growing mycobacteria was identified on the basis of growth characteristics, biochemical and lipid profiles, and nucleic acid analyses. The isolates showed growth at 22 to 37 degrees C, yellow pigmentation, and negative tests for Tween 80 hydrolysis, nicotinic acid, nitrate reductase, and urease; tests for arylsulfatase, pyrazinamidase, and heat-stable catalase were variable. Analysis of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography and high-performance liquid chromatography indicated a distinctive pattern which was unlike those of other species. Determination of the 16S rRNA gene sequence showed a unique sequence closely related to Mycobacterium simiae and M. genavense. On the basis of DNA homology studies, we suggest that these organisms are representatives of a novel species, for which the name M. lentiflavum sp. nov. is proposed.

Bacterial Typing Techniques↗
PubMed1995

[Current developments in Mycobacteria diagnosis].

The reemergence of tuberculosis in the industrialized countries has hastened the development of new laboratory techniques. Hence, well-known shortcomings of traditional techniques such as the lack of a rapid and specific detection system, the delayed availability of species identification and drug susceptibility results, and the lack of a reliable method for determining strain identity for epidemiological purposes, have become immediate targets for implementing molecular biology techniques. In particular, nucleic acid amplification techniques, restriction fragment-length polymorphism and single-strand conformation polymorphism analyses have dramatically improved diagnostic timeliness and accuracy of mycobacteriology laboratory results. Our paper reviews recent developments and comments on the diagnostic applications of the new tools as compared to traditional techniques.

Amino Acid Sequence↗