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W Opferkuch

Publications and source records attributed to W Opferkuch.

At least 19 recordsLinked to original sources
PubMed1992

Biochemical studies of Helicobacter mustelae fatty acid composition and flagella.

The fatty acid compositions of Helicobacter mustelae whole cells, isolated phospholipids, and isolated lipopolysaccharides were analyzed by gas-liquid chromatography. Major phospholipid fatty acids were C16:0, C18:0, C18:1, and C19:0 cyc. In isolated lipopolysaccharides, 3-OH-C16:0, 3-OH-C14:0, C14:0, C16:0, and C18:0 were found. The lipid composition of H. mustelae thus showed pronounced differences from that of H. pylori. Flagella were purified by mechanical shearing and centrifugation steps. In all H. mustelae strains, the flagellin had an apparent molecular mass of 53 kDa and was thus the same size as H. pylori flagellin. The flagellin of strain NCTC 12032 was further purified and subjected to N-terminal amino acid sequence analysis. The first 10 amino acids were identical to those of H. pylori flagellin, but the next 5 were different. Significant homology was also found with flagellins of other bacteria.

Amino Acid Sequence↗
PubMed1992

[Modified combined omeprazole/amoxicillin therapy for Helicobacter pylori eradication: a pilot study].

Patients with H.pylori positive peptic ulcer disease were treated with a two weeks regimen consisting of 20 mg omeprazole twice daily and 500 mg amoxicillin six times daily. Subsequently, an H2-receptor antagonist was started (300 mg ranitidine) at night time for four weeks. Before and one month after completion of antibiotic therapy an upper GI-tract endoscopy was performed for determination of H.pylori infection [biopsy urease test (BUT), specific culture and histologic demonstration]. A total of 12 patients completed the study protocol. H.pylori eradication, defined as a negative result in BUT, culture and histology) four weeks after completion of the combined omeprazole/amoxicillin treatment regimen was achieved in 91.6% (11 of 12 patients). Complete ulcer healing was confirmed in all patients. A stomatitis was observed in one female patient as a possible side effect of antibiotic treatment, but this did not necessitate discontinuation of therapy. Only complicated drug regimen with many side effects have been available so far for successful eradication of H.pylori. Thus, the present drug combination might prove as an effective therapeutic option in the future. These data, however, await confirmation in larger study population.

Adult↗
PubMed1991

Imipenem resistance in Acinetobacter baumanii is due to altered penicillin-binding proteins.

The comparison of a clinical Acinetobacter baumanii isolate (strain No. 4852/88) and its selected imipenem-resistant (IMR) clone exhibited a complex reorganization of the penicillin-binding proteins (PBPs) with diminished labelling of all PBPs except the 24-kD PBP which showed an increased binding of 14C-penicillin. This protein could not be saturated by preincubation of membranes with imipenem at 8-fold the MIC of imipenem, thus indicating PBP alterations responsible for imipenem resistance. In A. baumanii 4852/88 seven PBPs with the apparent molecular weights of 94, 84, 65, 61, 48, 40 and 24 kD could be detected. beta-Lactamase production was barely detectable in any case and could not be enhanced in the presence of various beta-lactams as the inducer. The outer membrane proteins were found identical in both the wild-type strain and the Im clone. So far, imipenem-resistant A. baumanii isolates have been isolated twice in our diagnostic laboratory; however, no implications on the future relevance of the above findings can be made.

Acinetobacter↗
PubMed1991

[The effect of sulbactam on the in vitro activity of mezlocillin, piperacillin and cefotaxime].

The in vitro activity of mezlocillin (MZL, CAS 51481-65-3), piperacillin (PIP, CAS 61477-96-1) and cefotaxim (CTX, CAS 63527-52-6) alone and in combination with sulbactam (SBT; CAS 68373-14-8) against mezlocillin-resistant pathogens was determined in a multicenter study. A total of 870 strains were investigated (481 Enterobacteriaceae, 57 Pseudomonas aeruginos, 41 Acinetobaster spp., 194 Bacteroides fragilis, and 97 Staphylococcus spp.). Determinations of MIC were performed according to DIN-guidelines (agar-dilution method for aerobes and microbroth-dilution method for anaerobes). Sulbactam was added in fixed concentrations of 5 mg/l and 10 mg/l. In all sulbactam-combinations examined mean MIC as well as MIC50 and MIC90 were reduced compared to the respective values for the antibiotics alone. Consequently, percentages of susceptible strains increased significantly: i.e. for Enterobacteriaceae: MZL 1% vs. MZL + 10 mg/l SBT 53%; PIP 4% vs. PIP + 10 mg/l SBT 54%; CTX 52% vs. CTX + 10 mg/l SBT 68%. The effect of sulbactam was most pronounced in Bacteroides spp. with an increase in susceptible strains from 2% to 97% for MZL, from 6% to 95% for PIP and from 7% to 98% for CTX. The results indicate that by adding sulbactam the in vitro activity of mezlocillin, piperacillin and cefotaxim against resistant pathogens is augmented significantly. In addition, the spectrum of antibacterial activity is extended to anaerobic pathogens such as Bacteroides spp. The availability of sulbactam as a monosubstance for combination with various beta-lactam-antibiotics thus represents a useful improvement of therapeutic options in bacterial infections.

Acinetobacter↗
PubMed1990

Isolation and characterization of monoclonal antibodies directed against different epitopes of type-1-like fimbriae from a multifimbriated E. coli strain.

Monoclonal antibodies (MAbs) were raised against purified fimbriae isolated from the uropathogenic E. coli strain WF96 (O7:K1:H6:F11rel,F10). This strain expresses at least four different types of fimbriae. 11 MAbs were selected for further characterization. They are directed against epitopes of a fimbrial type which is composed of 19.5 kDa subunits. It resembles type 1 fimbriae with regard to its high resistance to disruption by SDS. The MAbs were tested for crossreactivity to type 1 fimbriae and other fimbriae with known F-serotypes by ELISA. Two of these MAbs, Pili III 2F7 and Pili III 68C5, were directed against an epitope which was also found on MS fimbriae (type 1). Thus type 1 like fimbriae of E. coli WF96 share at least one epitope with MS fimbriae. Nevertheless, the antigenic properties of these two fimbrial types were found not to be completely identical, since all the other 9 MAbs were not crossreactive. The MAbs were not able to inhibit haemagglutination of erythrocytes of different species and thus not directed against adhesive sites of the fimbriae. All the epitopes detected by MAbs were accessible on native fimbriae; some of them were also detectable on denatured fimbrial subunits. Electron micrographs revealed that these epitopes were evenly distributed on the fimbrial organelle.

Animals↗
PubMed1990

Intermediate filaments vimentin and desmin share epitopes with M 1 protein of group A streptococci.

The cross reactivity of the murine monoclonal antibody PM II 40 against human glomeruli with streptococcal type 1 M protein was investigated. The antibody PM II 40 recognized a protective epitope on a glomerulonephritis-associated M type 1 strain. A 23 kD streptococcal surface protein extracted by limited pepsin digestion reacted with PM II 40 in the Western immunoblot. The aminoterminal sequence of this peptide was identical to the known aminoterminal amino acid sequence of type 1 M protein. Human renal podocytes carry the cross-reactive antigen of the antibody PM II 40 as could be shown by electron microscopy. The podocytes cultured from isolated human glomeruli showed a fibrillar pattern with the antibody in the immunofluorescence test. An anti-vimentin antibody and the antibody PM II 40 recognized the same proteins with molecular weights of 54, 52 and 43 kD of SDS-extracted isolated human glomeruli suggesting that vimentin is the glomerular antigen. The antibody PM II 40 not only react with vimentin but also with desmin suggesting that the recognized epitopes are distinct from that described by Kraus et al. for vimentin and type 1 M protein.

Amino Acid Sequence↗
PubMed1990

Influence of beta-lactam antibiotics on serum resistance of K1-positive blood culture isolates of Escherichia coli.

The K1-positive strains of Escherichia coli are a group with considerable clinical importance, serum resistance being a common virulence factor of these strains. In the present paper, the influences of cephaloridine, imipenem, and ceftazidime on the serum resistance of eight serum-resistant K1-positive E. coli blood culture isolates with smooth-type lipopolysaccharide were studied. All strains were rendered more serum sensitive by treatment with subinhibitory concentrations of antibiotics. The amount of the reduction of serum resistance was dependent on the concentration of the antibiotic. Amounts of K1 produced under the influence of the antibiotics were measured and were found to be reduced for almost all strains tested. To further test the hypothesis that antibiotic-induced reduction of serum resistance is mediated by inhibition of K1 expression, isogenic mutants of one strain were produced by selection for resistance against infection with K1-specific bacteriophages. These mutants were found to be highly serum sensitive. We conclude from this study that beta-lactam antibiotics can render K1-positive serum-resistant strains of E. coli highly serum sensitive and that this effect is mediated by inhibition of K1 expression.

Ceftazidime↗
PubMed1990

The capsular polysaccharide is a major determinant of serum resistance in K-1-positive blood culture isolates of Escherichia coli.

Serum resistance is a major virulence factor of gram-negative bacteria, and K-1 polysaccharide has been shown to contribute to serum resistance in selected strains. To obtain further information about the role of K-1 in serum resistance and to find out whether loss of the ability to produce K-1 can induce loss of serum resistance, we studied the serum resistance of mutants derived from completely serum-resistant, K-1-positive blood culture isolates of Escherichia coli by selection for resistance to infection with K-1 specific bacteriophages. The amounts of K-1 polysaccharide produced by wild-type strains and mutants were measured, and outer membrane protein and lipopolysaccharide (LPS) patterns were analyzed. In each group of mutants, several highly serum-sensitive strains were found. All mutant strains expressed less K-1 than did the corresponding wild-type strains. Mutants that became highly serum sensitive always had less K-1 than did mutants with less-pronounced changes of serum resistance. A few mutants derived from different wild-type strains showed increased expression of outer membrane proteins with molecular weights of about 46,000 and 67,000. All of the wild-type strains examined had smooth-type LPS, and only two mutants had altered LPS structures; alterations of mutants in outer membrane proteins and LPS could not be correlated with alterations of serum resistance. The results indicate that for K-1-positive blood culture strains of E. coli, K-1 expression is a prerequisite for serum resistance, and loss of ability to synthesize K-1 leads to loss of serum resistance.

Antigens, Bacterial↗
PubMed1990

Unusual fatty acid substitution in lipids and lipopolysaccharides of Helicobacter pylori.

Cellular fatty acids, phospholipid fatty acids, and lipopolysaccharide fatty acids of four strains of Helicobacter pylori were analyzed by gas-liquid chromatography. The presence of myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, 19-carbon cyclopropane fatty acid, beta-hydroxypalmitic acid, and beta-hydroxystearic acid was confirmed. In phospholipids, myristic acid and 19-carbon cyclopropane fatty acid were the major fatty acids. Hydroxy fatty acids and unsaturated fatty acids were not detected or occurred only in small amounts. The major fatty acids of lipopolysaccharides were stearic acid, beta-hydroxypalmitic acid, and beta-hydroxystearic acid. Unsaturated fatty acids and 19-carbon cyclopropane fatty acid were not found. The unusual compositions of H. pylori phospholipid and lipopolysaccharide fatty acids may have important implications for the taxonomy, physicochemical membrane properties, and biological activity of lipopolysaccharides.

Campylobacter↗
PubMed1989

A third mechanism of serum resistance in Escherichia coli.

15 serum-resistant strains of E. coli group III characterized by binding of both C3 and factor H in the immunofluorescence test were studied in respect of the mechanism on which serum resistance is based in these strains. Serum resistance in 7 strains were found to be established by one of the mechanisms first described by Joiner et al. or by Kubens et al. The classification of these strains should therefore be altered. The binding and consumption of C5 as well as the binding of C9 was investigated for the remaining 8 strains. All strains were found to bind the two complement components which are part of the membrane attack complex (MAC) without causing cell death. These results suggest that resistance in strains of group III is based on a third mechanism which shows similarities to data obtained for other species but has not yet been described for E. coli.

Blood Bactericidal Activity↗
PubMed1989

Ultrastructure and chemical analysis of Campylobacter pylori flagella.

Flagella of Campylobacter pylori were analyzed by electron microscopy and purified, and the molecular weight of the flagellin was determined. Isolation of flagella was performed by mechanical shearing from the cell surface, sucrose density gradient centrifugation, and Sepharose CL-4B gel chromatography. The flagella of C. pylori differ from those of other Campylobacter species and of most other bacteria by the presence of a flagellar sheath. The sheath narrows at the end and is linked to a club-shaped terminal structure. The molecular weight of C. pylori flagellin was 51,000.

Campylobacter↗
PubMed1989

[Serodiagnosis of Campylobacter pylori].

The colonization of gastric mucosa with Campylobacter pylori can be detected by serological methods. ELISA and immunoblot methods are currently being employed for detection of antibodies against Campylobacter pylori. In general, both tests will differentiate between Campylobacter pylori positive and Campylobacter pylori negative patients. However, 5-10% of persons with negative cultures for Campylobacter pylori have positive serological tests, but only very few patients with Campylobacter pylori associated with chronic gastritis have negative serological tests. This is true for tests detecting IgG and IgA antibodies. Tests for IgM antibodies have not been found to be useful. Immunoblot analyses have shown that detection of antibodies against a 100-120 KD antigen has a high specificity for Campylobacter pylori infection. In a small study we evaluated the possible use of serological testing for follow-up studies on patients after Campylobacter pylori therapy. We found that patients who became Campylobacter pylori negative after therapy showed a significant decline of serum IgG titers against Campylobacter pylori.

Antibodies, Bacterial↗
PubMed1989

[Campylobacter pylori: clinical correlations and prospective comparative studies of various diagnostic techniques].

The diagnostic performance of two different urease tests and of histologic search after modified Giemsa staining to detect Campylobacter pylori (CP) colonization of the upper gastrointestinal tract was prospectively investigated in 215 esophagogastroduodenoscopies, by using a sensitive culture technique as reference. Single antral urease tests had a high specificity of 95-96%, but a limited sensitivity of 78-83%, which increased to 91-94%, when one antral and one additional body biopsy were submitted to the biochemical tests. Giemsa stains were very sensitive, but less specific. The rate of colonization was similar in antrum and body biopsies, and increased with age. There was a close association of Campylobacter pylori colonization with duodenal and to a lower degree with gastric ulcer disease, but especially with gastritic mucosal changes. CP was never detected in patients without gastritis. Therefore, submitting one antral and one body biopsy specimen to validated urease tests represents a sensitive (91-94%) and specific (93%) method to detect Campylobacter pylori colonization, which appears to be a diffuse phenomenon affecting antral and body mucosae with similar frequency.

Biopsy↗