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Helicobacter Pylori Strains (helicobacter + pylori_strain)
Selected AbstractsAntimicrobial Susceptibility of Helicobacter pylori Strains in a Random Adult Swedish PopulationHELICOBACTER, Issue 4 2006Tom Storskrubb Abstract Background and Aim:, Antimicrobial resistance in Helicobacter pylori is a growing problem and has become an important factor leading to eradication failure. Information on antimicrobial susceptibility is important for selection of an optimum treatment regimen. The resistance rate in a random population has not been studied previously. Methods:, A random Swedish population sample (n = 3000, age 20,81 years) was surveyed using a mailed validated questionnaire assessing gastrointestinal symptoms (response rate of 74%). One-third of the responders was invited, in random order, and accepted an esophagogastroduodenoscopy with biopsies for H. pylori culture and histology. Subjects were not treated for their H. pylori infection but a minimum inhibitory concentration of metronidazole, clarithromycin, amoxicillin, and tetracycline for the H. pylori isolates (n = 333) was determined by agar dilution. Prescribed antibiotic in the area was recorded. Results:, Irrespective of symptomatology, 16.2% of the isolated H. pylori strains were resistant to metronidazole, 1.5% to clarithromycin, 0% to amoxicillin, and 0.3% to tetracycline. The antibiotic consumption was low from an international perspective. Conclusion:, The resistance to the antibiotics was lower than expected from patient sample studies, especially for clarithromycin, most probably due to a restrictive prescription policy in the area. Introduction of a test-and-treat strategy in Sweden would only marginally affect the usage of clarithromycin. [source] Different Helicobacter pylori Strains Colonize the Antral and Duodenal Mucosa of Duodenal Ulcer PatientsHELICOBACTER, Issue 2 2000Ann-Catrin E. Thoreson Background. We have investigated the possibility that the same patients may be colonized by Helicobacter pylori strains of different genotypes or phenotypes in the antrum as compared to in the duodenum. The strains were typed for DNA fingerprints, different lipopolysaccharides (LPS), and Lewis antigen expression on the O,side chains of LPS. Materials and Methods. Polymerase chain reaction (PCR) amplifications using primer sequences (i.e., the Enterobacterial Repetitive Intergenic Consensus [ERIC]) and randomly amplified polymorphic DNA (RAPD) elements were performed to asses chromosomal DNA diversity between H. pylori strains. The expression of different LPS types and Lewis antigens in the various H. pylori isolates were determined by whole bacterial enzyme-linked immunosorbent assays using monoclonal antibodies. Results. Duodenal ulcer patients had different H. pylori genotypes in the duodenum as compared to in the antrum as shown by ERIC-PCR (44%) and by RAPD-PCR (75%). Different DNA patterns were found among the strains that were isolated from various regions of the duodenum in 4 of 16 patients (25%) as shown by ERIC-PCR and in 8 of 16 patients (50%) as shown by RAPD-PCR. Sixty-three percent of the duodenal ulcer patients had H. pylori strains with a different Lewis antigen phenotype in the duodenum as compared to in the antrum, and 3 of 16 patients (19%) had strains with different Lewis antigens expressed by strains from different duodenal biopsies from the same patient. Conclusion. The results suggest that a mixed population of different H. pylori strains with marked variation, both genotypically and phenotypically, colonize the same patient. [source] Synthesis of the Trisaccharide Repeating Unit of the Atypical O-Antigen Polysaccharide from Danish Helicobacter pylori Strains Employing the 2,-Carboxybenzyl Glycoside.CHEMINFORM, Issue 7 2005Yong Tae Kwon No abstract is available for this article. [source] Endotoxic and immunobiological activities of a chemically synthesized lipid A of Helicobacter pylori strain 206,1FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1-2 2003Tomohiko Ogawa Abstract A synthetic lipid A of Helicobacter pylori strain 206-1 (compound HP206,1), which is similar to its natural lipid A, exhibited no or very low endotoxic activities as compared to Escherichia coli -type synthetic lipid A (compound 506). Furthermore, compound HP206-1 as well as its natural lipid A demonstrated no or very low mitogenic responses in murine spleen cell. On the other hand, compound HP206-1 showed a weaker but significant production of interleukin-8 in a gastric cancer cell line, MKN-1, in comparison with compound 506. Furthermore, compound HP206-1 exhibited induction of tumor necrosis factor-, production in human peripheral blood mononuclear cells and the cytokine production was clearly inhibited by mouse anti-human Toll-like receptor (TLR) 4 monoclonal antibody HTA125. Our findings indicate that the chemically synthesized lipid A, mimicking the natural lipid A portion of lipopolysaccharide from H. pylori strain 206-1, has a low endotoxic potency and immunobiological activities, and is recognized by TLR4. [source] Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of HP1352, a putative DNA methyltransferase in Helicobacter pyloriACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2003Katja Schirwitz The putative methyltransferase gene HP1352 from Helicobacter pylori strain 26695 was heterologously expressed in Escherichia coli. The 359-amino-acid gene product was purified and crystallized. The crystals belong to space group I212121 and show diffraction to at least 2.5,Å resolution. The unit-cell parameters are a = 69.6, b = 86.6, c = 140.0,Å. A greater than 90% complete native data set has been collected and structure determination using the molecular-replacement method is ongoing. [source] Different Helicobacter pylori Strains Colonize the Antral and Duodenal Mucosa of Duodenal Ulcer PatientsHELICOBACTER, Issue 2 2000Ann-Catrin E. Thoreson Background. We have investigated the possibility that the same patients may be colonized by Helicobacter pylori strains of different genotypes or phenotypes in the antrum as compared to in the duodenum. The strains were typed for DNA fingerprints, different lipopolysaccharides (LPS), and Lewis antigen expression on the O,side chains of LPS. Materials and Methods. Polymerase chain reaction (PCR) amplifications using primer sequences (i.e., the Enterobacterial Repetitive Intergenic Consensus [ERIC]) and randomly amplified polymorphic DNA (RAPD) elements were performed to asses chromosomal DNA diversity between H. pylori strains. The expression of different LPS types and Lewis antigens in the various H. pylori isolates were determined by whole bacterial enzyme-linked immunosorbent assays using monoclonal antibodies. Results. Duodenal ulcer patients had different H. pylori genotypes in the duodenum as compared to in the antrum as shown by ERIC-PCR (44%) and by RAPD-PCR (75%). Different DNA patterns were found among the strains that were isolated from various regions of the duodenum in 4 of 16 patients (25%) as shown by ERIC-PCR and in 8 of 16 patients (50%) as shown by RAPD-PCR. Sixty-three percent of the duodenal ulcer patients had H. pylori strains with a different Lewis antigen phenotype in the duodenum as compared to in the antrum, and 3 of 16 patients (19%) had strains with different Lewis antigens expressed by strains from different duodenal biopsies from the same patient. Conclusion. The results suggest that a mixed population of different H. pylori strains with marked variation, both genotypically and phenotypically, colonize the same patient. [source] Association of peptic ulcer with increased expression of Lewis antigens, but not vacuolating cytotoxin activity or babA2 gene status, in Helicobacter pylori strains from ChinaJOURNAL OF DIGESTIVE DISEASES, Issue 1 2006Peng Yuan ZHENG OBJECTIVE: Controversies exist regarding the virulence factors, such as vacA, babA2 and Lewis blood group antigens, of Western and Asian strains of Helicobacter pylori. The aim of the present study was to determine the significance of these potential virulence factors in the Chinese population. METHODS: Seventy-two strains of H. pylori isolated from patients in Zhengzhou, China, including 43 cases of peptic ulcer (PU) and 29 cases of chronic gastritis, were determined. Vacuolating cytotoxin assay was performed by HeLa cells. The expression of Le blood group antigens (Lea, Leb, Lex and Ley) was performed by enzyme-linked immunosorbent assay (ELISA). babA2 gene was identified by polymerase chain reaction. Frequencies were compared using two-tailed Fisher's exact test. Cytotoxin activities were compared using Spearman's rank correction test. RESULTS: Vacuolating cytotoxin activity was detected in 61 of the 72 strains (84.7%), but there was no significant difference in vacuolating cytotoxin activity (83.7% vs 86.2%, P = 0.821) or titer (4.4 ± 3.8 vs 4.2 ± 4.1, P = 0.876) between the PU and gastritis strains. Significantly more PU strains expressed two or more Lewis antigens (Lex, Ley, Lea or Leb) than strains from the chronic gastritis patients (90.7% vs 65.5%, P = 0.029). Of the 43 strains from PU patients, 17 (39.5%) were positive for babA2, compared with 11 (38.5%) of the 29 strains from gastritis patients (P = 0.924). There was no significant difference in the vacuolating cytotoxin activity or titer between strains expressing two or more Lewis antigens and less than two antigens (84.5% vs 85.7%, P = 1.000; 4.4 ± 4.2 vs 4.3 ± 3.2, P = 0.965). Of the 72 H. pylori strains, 28 were babA2 positive, of which 24 were cytotoxic, compared with 37 of 44 babA2-negative strains (P = 1.000). CONCLUSION: The present study suggests that PU is associated with increased Lewis antigen expression, but not vacuolating cytotoxin production or the presence of babA2, in the H. pylori strains in the Chinese population. [source] Analysis of drug resistance and virulence-factor genotype of Irish Helicobacter pylori strains: is there any relationship between resistance to metronidazole and cagA status?ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 7 2009I. TANEIKE Summary Background,Helicobacter pylori infection is eradicated with antimicrobial agents and drug-resistant strains make successful treatment difficult. Geographical variations in virulence-factor genotype also exist. Aim, To evaluate prevalence of drug resistance and virulence-factor genotype in Irish H. pylori strains and to investigate if there is any relationship between drug resistance and genotype. Methods,Helicobacter pylori strains isolated from 103 patients were examined. Antimicrobial susceptibilities were tested by Etest. The virulence-factor genotypes were determined using PCR. Frequencies of spontaneous metronidazole-resistance were measured in vitro. Results, Metronidazole resistance was present in 37.9% of strains examined. 16.5% of strains were clarithromycin-resistant and resistance to both agents observed was found in 12.6% of strains. 68% of strains were cagA+. The dominant vacA type was s1/m2, followed by s1/m1 and s2/m2. The metronidazole resistance rate in cagA, group was significantly higher than in cagA+ (P = 0.0089). Spontaneous resistance to metronidazole in cagA, occurred in higher frequency when compared with cagA+. Conclusions,cagA+ and vacAs1/m2 type was the dominant genotype in Irish H. pylori strains. Significant rates of metronidazole resistance were observed in cagA, group. cagA, strains tend to acquire metronidazole resistance in vitro. Absence of cagA might be a risk factor in development of metronidazole resistance. [source] Anti- Helicobacter pylori activity of Lactobacillus delbrueckii subsp. bulgaricus strains: preliminary reportLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009L. Boyanova Abstract Aims:, To evaluate the activities of six Lactobacillus delbrueckii subsp. bulgaricus (LB) strains against 30 Helicobacter pylori strains by agar-well diffusion method. Methods and Results:, LB cultures [4 × 108,4 × 109 CFU ml,1) either were prepared in milk at their native pH, 3·8,5·0, or were adjusted to pH 6·4,7·7. At low and neutralized pH, LB strains inhibited the growth by 40,86·7% and 16·7,66·7% of H. pylori strains, respectively. LB activity was strain-dependent. At low and neutralized pH, one and five H. pylori strains, respectively, were not inhibited by any LB strain. LB2 and LB3, taken together, were active against most metronidazole and clarithromycin resistant strains. Conclusions:, All LB strains inhibited a number of H. pylori strains, including also antibiotic resistant strains. LB activity was strain-dependent and better at low pH. At low pH values, the most active LB strains were LB1, LB2 and LB3, inhibiting 86·7% of H. pylori strains, while at neutralized pH values, the most active LB strains were LB2 and LB3, inhibiting 53·3 and 66·7% of H. pylori strains, respectively. Significance and Impact of the Study:, LB could be utilized in the treatment or prophylaxis of H. pylori infection and warrants clinical investigations. [source] Overcoming the restriction barrier to plasmid transformation of Helicobacter pyloriMOLECULAR MICROBIOLOGY, Issue 5 2000John P. Donahue Helicobacter pylori strains demonstrate substantial variability in the efficiency of transformation by plasmids from Escherichia coli, and many strains are completely resistant to transformation. Among the barriers to transformation are numerous strain-specific restriction-modification systems in H. pylori. We have developed a method to protect plasmid DNA from restriction by in vitro site-specific methylation using cell-free extracts of H. pylori before transformation. In two cases, plasmid DNA treated with cell-free extracts in vitro acquired the restriction pattern characteristic of genomic DNA from the source strain. Among three strains examined in detail, the transformation frequency by treated plasmid shuttle and suicide vectors was significantly increased compared with mock-treated plasmid DNA. The results indicate that the restriction barrier in H. pylori can be largely overcome by specific DNA methylation in vitro. The approach described should significantly enhance the ability to manipulate gene function in H. pylori and other organisms that have substantial restriction barriers to transformation. [source] In vitro anti- Helicobacter pylori potential of methanol extract of Allium ascalonicum Linn. (Liliaceae) leaf: susceptibility and effect on urease activityPHYTOTHERAPY RESEARCH, Issue 5 2004Bolanle A. Adeniyi Abstract The crude methanol extract of the leaf of Allium ascalonicum was screened in vitro against ,ve strains of Helicobacter pylori (Hp) (ATCC 24376, UCH 97001, UCH 97009, UCH 98026 and UCH 99039) for antibacterial activity by the agar diffusion method in Mueller-Hinton agar supplemented with de,brinated horse blood. All the strains were inhibited by the extract to varying degrees. The minimum inhibitory concentrations (MICs) of the extract against all the tested strains ranged from 6.25 to 12.5 mg/mL. The effects of increasing concentrations of the extract on the urease activity of three of the Helicobacter pylori strains were investigated further. The results showed that increasing the concentration of the extract decreased the urease activity of all the strains tested. Phytochemical screening of the plant showed that it contains alkaloids, cardiac glycosides and saponins. The anti-Hp activity observed is discussed in relation to the chemical constituents reportedly isolated from these plants and their traditional uses. The result of this work suggests that Allium ascalonicum has some therapeutic potential against Helicobacter pylori infection, which could be explored for patients with gastroduodenal disorders. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparative proteomic analysis of Helicobacter pylori strains associated with iron deficiency anemiaPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2006Shin Ae Park No abstracts. [source] | ||||||||||||||||