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R Ansorg

Publications and source records attributed to R Ansorg.

At least 37 records · Page 2Linked to original sources
PubMed1996

Association between incidence of Aspergillus antigenemia and exposure to construction works at a hospital site.

During the course of extensive building activity in the vicinity of bone marrow transplantation wards, the patients were routinely screened for the occurrence of Aspergillus galactomannan antigen in serum. In 19 (6.7%) out of 285 patients, an antigenemia was detected. Eleven (58%) of the 19 antigenemic patients suffered from autopsy-proven or clinically suspected invasive aspergillosis. The yearly incidence of antigenemic patients differed significantly, ranging from 0% in the year without building activities to 20.9% in the year with major activities, particularly interior completion works and landscaping. It is concluded that Aspergillus antigen monitoring of bone marrow transplant recipients has a limited value for the diagnosis of manifest invasive aspergillosis. However, it it epidemiologically useful to assess the extent of intensive contact with aspergilli and to control the effectivity of preventive measures.

Antigens, Fungal↗
PubMed1996

Susceptibility of Helicobacter pylori to simethicone and other non-antibiotic drugs.

The antifoaming agent simethicone (Lefax), the protease inhibitor gabexate mesilate (FOY), the antimycotic ketoconazole, and the hydroxyl scavangers dimethylsulphoxide (DMSO) and allopurinol were investigated for growth inhibition of Helicobacter pylori and representative strains of other bacterial species. H. pylori were selectively inhibited by 64-128 mg/L of simethicone, 64-128 mg/L gabexate mesilate, and 16-64 mg/L ketoconazole. Dimethylsulphoxide and allopurinol showed no antibacterial effect at concentrations used therapeutically. It is concluded that gabexate mesilate, ketoconazole and, particularly, simethicone are candidates for treatment of H. pylori infection.

Antifoaming Agents↗
PubMed1996

Comparison of the E test and a proportion dilution method for susceptibility testing of Mycobacterium avium complex.

The newly developed E test was compared with an extended 1% proportion dilution method for determining the susceptibility of Mycobacterium avium complex (MAC) strains to amikacin, streptomycin, fusidic acid, rifampicin, clarithromycin, ciprofloxacin, ofloxacin and fleroxacin. For all antibiotics tested except clarithromycin and ciprofloxacin, no more than one strain gave a different susceptibility result with the two methods. The discrepant results occurred near the chosen breakpoint concentration of clarithromycin and outside the concentration range of the E test for ciprofloxacin. For the minimum inhibitory concentration (MIC) values obtained within the range of antibiotic concentrations tested, there was good correlation between the two methods; the MICs differed by more than one two-fold dilution in no more than two strains per antibiotic. It is concluded that the E test is suitable for susceptibility testing of MAC.

Diffusion↗
PubMed1996

Susceptibility of Helicobacter pylori and Candida spp. to the east African plant Terminalia spinosa.

Trees of the genus Terminalia have long been used in the traditional medicine of Kenya (East Africa). In an ethnopharmacological approach, extracts of the stem bark of Terminalia spinosa were investigated for antibacterial and antifungal activity. The extracts were active against Helicobacter pylori, with the following minimum inhibitory concentrations (MIC): MIC50 of 125 mg/l, MIC90 of 250 mg/l, and MIC-range of 62.5-500 mg/l. Yeasts of the genus Candida showed a similar susceptibility. The results indicate that the plant if a source of antimicrobial compounds with therapeutic potential.

Bacteria↗
PubMed1995

Comparison of the E test and a proportion dilution method for susceptibility testing of Mycobacterium tuberculosis.

Minimal inhibitory concentrations (MICs) of amikacin, streptomycin, fusidic acid, rifampicin, clarithromycin, ciprofloxacin, ofloxacin, and fleroxacin were determined by the E test for 20 strains of Mycobacterium tuberculosis. The resulting discrimination in resistant or sensitive strains was compared with the results of an extended proportion dilution method. There were no more than three strains per antibiotic with different ratings with the exception of ciprofloxacin and ofloxacin. In these discrepant cases, the breakpoint concentrations had a position at the top of the test strip, which may be unfavourable for MIC reading. The MICs of streptomycin (1-2 mg/l) and rifampicin (2-4 mg/l) for the control strain M. tuberculosis H37Rv (ATCC 27,294) were close to the reference values according to the German standard DIN 58,943. It is concluded that the E test is suitable for susceptibility testing of slowly growing M. tuberculosis isolates.

Amikacin↗
PubMed1995

Determination of itraconazole and hydroxy-itraconazole in sera using high-performance-liquid-chromatography and a bioassay.

The concentrations of itraconazole and its active metabolite, hydroxy-itraconazole, were determined in the sera of 49 patients having received itraconazole for therapeutic or prophylactic purposes. Measurements by HPLC were compared with a biological assay using a strain of Paecilomyces variotii as test organism and itraconazole as standard. The concentration of hydroxy-itraconazole in serum was on average 1.6 times higher than the concentration of itraconazole. The sum of itraconazole and hydroxy-itraconazole concentrations determined by HPLC showed a linear relationship with the concentrations obtained by the bioassay (r = 0.94). The biological method gives approximately 20% higher values than the HPLC method indicating that hydroxy-itraconazole is biologically more active than itraconazole. As the values of the Paecilomyces variotii bioassay are in the same range as the HPLC measurements, it is concluded that both methods are suitable for the monitoring of itraconazole medication.

Antifungal Agents↗
PubMed1995

Metronidazole susceptibility testing of Helicobacter pylori with the PDM epsilometer test (E test).

The bacteriostatic activity of metronidazole against Helicobacter pylori was determined with the PDM epsilometer test (E test) and with an agar dilution test. Both methods correlated in the minimum inhibitory concentration (MIC) ranges (< or = 0.5- > 32 mg/l) and in the MIC 50 (E test: 1 mg/l; agar dilution test: 2 mg/l) and MIC 90 (> 32 mg/l) values. However, comparison of test results of single strains revealed that 14 out of 105 strains (13.3%) were classified as resistant by one method but classified susceptible by the other. The correlation coefficient of 0.71 also indicated a low congruence of test results. It is concluded that both methods should be used in order to ascertain all strains resistant to metronidazole.

Drug Resistance, Microbial↗
PubMed1995

Imipenem inhibits in vitro activity of amphotericin B directed against Aspergillus fumigatus.

A decrease of the susceptibility of Aspergillus fumigatus strains to amphotericin B was found when tested in combination with high concentrations (128-2048 mg/l) of the antibacterial agent imipenem by checkerboard titration and agar diffusion assay. Only bacteriologically active imipenem showed the antagonism. The mechanism of action is unknown. However, imipenem and amphotericin B did not react directly, as shown by checkerboard titration with bacterial strains as well as by HPLC analysis. It is concluded that imipenem medication may influence the efficacy of amphotericin B treatment in aspergillosis.

Amphotericin B↗
PubMed1995

Cat owners' risk of acquiring a Helicobacter pylori infection.

In order to obtain information as to whether or not domestic cats are a significant reservoir for human Helicobacter pylori infection, H. pylori antibodies were determined in 59 members of cat protection clubs and in an age- and sex-matched control group. Using four different assay systems, the prevalence rates of H. pylori antibodies in the cat owner group compared to the control group were 29% and 34%, respectively (Pyloriset Dry), 27%/42% (Pyloriset EIA-G), 14%/29% (Pyloriset EIA-A), and 37%/42% (Cobas Core EIA). The differences between the two groups in the prevalence of H. pylori antibodies were not statistically significant. It is concluded that cat owners, even if they have a very intensive contact with their pets, do not have a higher risk of H. pylori infection than the general population.

Adult↗
PubMed1994

Aspergillus antigenuria compared to antigenemia in bone marrow transplant recipients.

The detection of galactomannan antigen in urine was investigated in 26 bone marrow transplant recipients using an Aspergillus latex agglutination test (Pastorex). After modification of the method, which was originally devised for serum testing, the detection limit in native urine was approximately 20 ng/ml. Antigen was found in 79 (36.4%) of 217 serial urine samples, compared to 40 (11.8%) of 340 serum samples. As a rule, antigenuria preceded antigenemia and was more persistent. The sensitivity, specificity, positive predictive value and negative predictive value of antigenuria for autopsy-proven aspergillosis and clinically suspected Aspergillus infection were 57%, 53%, 31% and 77%, respectively, while those of antigenemia were 43%, 53%, 25% and 71%. It is concluded that urine testing is more reliable than serum testing for the detection of Aspergillus galactomannan. The detection of antigen, however, whether in serum or in urine, allows no clear distinction between Aspergillus infection and exposure to non-infectious Aspergillus antigens.

Adolescent↗
PubMed1994

No cultural detection of Helicobacter pylori in dental plaque.

Helicobacter pylori causes human type B gastritis and is involved in the etiology of peptic ulcer disease. The routes of transmission of H. pylori are still unclear. The microorganism may be transmitted orally, since H. pylori has been detected in dental plaques. To confirm the hypothesis that dental plaques are a reservoir of H. pylori, 100 dental plaque specimens from 55 dental surgery patients were incubated on one nonselective and up to four selective agar media for the detection of H. pylori. In addition, urease activity of the plaque material was tested, and the gingival status of the patients was assessed. H. pylori was not cultivated from any of the specimens investigated. Plaque material from 12 patients with moderate and severe gingivitis showed urease activity. The results do not confirm the hypothesis that dental plaques are a relevant reservoir of viable H. pylori cells. However, non-cultivatable forms of H. pylori may survive in dental plaques. Urea cleaving activity of dental plaque may be a marker of gingival inflammation.

Adolescent↗
PubMed1993

Cell-associated haemolytic activity of Helicobacter pylori.

Helicobacter pylori cells cultured on solid medium were quantitatively tested for haemolytic activity against erythrocytes of man, sheep, the guinea pig and rabbit. Using 4-day and 8-day cultures of two standard strains (ATCC 43504, IMMi 676), human erythrocytes were not lysed by 10% bacterial suspensions. Rabbit erythrocytes were the most sensitive to 8-day cultures. Hot-cold incubation yielded the highest haemolysis titres. The extent of haemolysis strongly correlated with the number of bacterial cells. Supplementation of the test medium (PBS, pH 7.4) with L-cysteine, dithiothreitol, MgCl2, EDTA, cholesterol, lecithin or sphingomyelin did not influence the haemolysis titres. They were significantly reduced in the presence of pronase E, human serum, bovine serum albumin or CaCl2, and by heat treatment of the bacteria. Supplementation of the test medium with cardiolipin strongly increased the haemolysis titres. Comparing the cell-associated haemolytic activity of 18 strains, the titres ranged from < 2 to 64, with a median titre of 16. No correlation was found between the haemolytic activity and phospholipase C activity of the cell suspensions. It was concluded that the formation of lysophosphatides and non-enzymatic factors rather than a sulphydryl-activated cytolysin or phospholipase C are responsible for the cell-associated haemolytic activity. This property may be involved in the pathogenicity and virulence of Helicobacter pylori.

Animals↗
PubMed1993

Activity of antibiotics and azole antimycotics against Helicobacter pylori.

The bacteristatic and bactericidal activities of six antibiotics from different substance classes against Helicobacter pylori were determined. Ampicillin, imipenem, tetracycline, and amikacin inhibit the growth of all isolates at concentrations achievable in serum. Cefpirome and ofloxacin are ineffective against three and two of 41 strains, respectively. However, the minimum bactericidal concentrations (MBC) of the substances are two- to sixteen-fold higher than the minimum inhibitory concentrations (MIC). There is sufficient bactericidal activity of ampicillin and imipenem against all strains, but amikacin, ofloxacin, tetracycline, and cefpirome are unable to kill 2, 8, 12, and 18 of 25 strains, respectively, at concentrations achievable in serum. Differences between MIC and MBC of antibiotics may contribute to the explanation of therapy failures. In addition, the inhibitory activity of seven nitroimidazole antimycotics and the triazole fluconazole was evaluated. The nitroimidazole MICs range from 2 to 64 mg/l, with tioconazole, miconazole, bifonazole, and ketoconazole as the most active substances. Fluconazole, however, was ineffective at concentrations < or = 128 mg/l. The efficacy of the nitroimidazole antimycotics against H. pylori in vivo should be tested in a clinical trial.

Anti-Bacterial Agents↗
PubMed1992

Cholesterol binding of Helicobacter pylori.

H. pylori cells grown on cholesterol-free medium adsorb cholesterol from serum, egg yolk, and VDRL reagent. The binding of cholesterol does not influence the hydrophobicity of the cells. The haemagglutinating activity is slightly diminished. The cell-bound haemolytic activity is completely inhibited. The affinity of H. pylori for cholesterol probably acts as factor of chemotaxis and adherence.

Adsorption↗
PubMed1992

Rapid identification of Legionella species from a single colony by gas-liquid chromatography with trimethylsulphonium hydroxide for transesterification.

Transesterification of bacterial fatty acids to methyl esters with trimethylsulphonium hydroxide (TMSH) was compared with a conventional method for the identification of Legionella species by capillary gas chromatography. There was an extensive coincidence in the gas chromatographic profiles of bacterial fatty acid methyl esters (FAMEs) obtained by the two methods. However, the TMSH procedure needs less initial material and is much more simple and rapid. The chromatographic pattern of FAMEs obtained from a single colony is sufficient for the identification of the genus Legionella, and L. pneumophila can be clearly distinguished from other Legionella species.

Chromatography, Gas↗
PubMed1991

Flocculation of venereal disease research laboratory reagent by Helicobacter pylori.

Helicobacter pylori strains flocculated with Venereal Disease Research Laboratory (VDRL) reagent in a glass slide test. Other pathogenic bacterial and fungal strains were nonreactive. The specific VDRL reaction property of Helicobacter pylori indicates an affinity of the cells for lipoidal substances, and can be used as a diagnostic aid for species identification.

Bacteria↗
PubMed1991

Evaluation of techniques for isolation, subcultivation, and preservation of Helicobacter pylori.

With sheep blood agar (SBA), Belo Horizonte medium, and Brussels campylobacter charcoal agar, 104 strains of Helicobacter pylori were detected in 309 gastric biopsies. Each medium revealed only 69 to 71% of the strains. Ten strains grew solely on SBA, and four strains each grew on Belo Horizonte medium and Brussels campylobacter charcoal agar. Subculturing of 50 fresh H. pylori isolates on SBA revealed a progressive reduction in growth with increasing passage. Thirty strains stopped growing between passages two and seven. Four strains survived more than 20 passages. The preservation of fresh H. pylori isolates at -193 and -70 degrees C and by lyophilization was compared by use of 10% porcine mucin solution, fetal calf serum, and a commercial cryopreservative fluid. Of 30 strains, 77 to 90% could be recultivated on SBA after preservation at -70 degrees C in all three storage media. The data indicate that for the primary isolation of H. pylori, not only one selective medium but several selective media with different antibiotic supplements plus at least one nonselective medium should be used to yield the highest culture rates. Frequent subculturing of H. pylori on SBA selects strains which may not be representative of clinical isolates. Storage of fresh H. pylori isolates at -70 degrees C in 10% mucin solution is a simple and effective preservation procedure.

Culture Media↗