scholarly journals Helicobacter pylori Can Be Induced To Assume the Morphology of Helicobacter heilmannii

1999 ◽  
Vol 37 (4) ◽  
pp. 1045-1048 ◽  
Author(s):  
Paul T. Fawcett ◽  
Kathleen M. Gibney ◽  
Kathleen M. B. Vinette
Keyword(s):  
Helicobacter Pylori ◽  
Culture Collection ◽  
Blood Agar ◽  
Broth Culture ◽  
Differential Interference Contrast Microscopy ◽  
Single Strain ◽  
Helicobacter Heilmannii ◽  
Interference Contrast Microscopy ◽  
Collection Strain ◽  
H Pylori

Cultures of Helicobacter pylori obtained from the American Type Culture Collection (strain 43504) were grown as isolated colonies or lawns on blood agar plates and in broth culture with constant shaking. Examination of bacterial growth with Gram-stained fixed preparation and differential interference contrast microscopy on wet preparations revealed that bacteria grown on blood agar plates had a morphology consistent with that normally reported for H. pylori whereas bacteria from broth cultures had the morphologic appearance of Helicobacter heilmannii. Bacteria harvested from blood agar plates assumed an H. heilmannii-like morphology when transferred to broth cultures, and bacteria from broth cultures grew with morphology typical of H. pylori when grown on blood agar plates. Analysis by PCR of bacteria isolated from blood agar plates and broth cultures indicated that a single strain of bacteria (H. pylori) was responsible for both morphologies.

scholarly journals Slow Genetic Divergence of Helicobacter pylori Strains during Long-Term Colonization

2005 ◽  
Vol 73 (8) ◽  
pp. 4818-4822 ◽  
Author(s):  
Annelie Lundin ◽  
Britta Björkholm ◽  
Ilya Kupershmidt ◽  
Magnus Unemo ◽  
Peter Nilsson ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Genetic Divergence ◽  
Bacterial Species ◽  
Pcr Amplification ◽  
Genetic Change ◽  
Genetic Changes ◽  
Single Strain ◽  
Divergent Gene ◽  
Asymptomatic Adult ◽  
H Pylori

ABSTRACT The genetic variability of Helicobacter pylori is known to be high compared to that of many other bacterial species. H. pylori is adapted to the human stomach, where it persists for decades, and adaptation to each host results in every individual harboring a distinctive bacterial population. Although clonal variants may exist within such a population, all isolates are generally genetically related and thus derived from a common ancestor. We sought to determine the rate of genetic change of H. pylori over 9 years in two asymptomatic adult patients. Arbitrary primed PCR confirmed the relatedness of individual subclones within a patient. Furthermore, sequencing of 10 loci (∼6,000 bp) in three subclones per time and patient revealed only two base pair changes among the subclones from patient I. All sequences were identical among the patient II subclones. However, PCR amplification of the highly divergent gene amiA revealed great variation in the size of the gene between the subclones within each patient. Thus, both patients harbored a single strain with clonal variants at both times. We also studied genetic changes in culture- and mouse-passaged strains, and under both conditions no genetic divergence was found. These results suggest that previous estimates of the rate of genetic change in H. pylori within an individual might be overestimates.

scholarly journals Effect of Helicobacter pylori on Polymorphonuclear Leukocyte Migration across Polarized T84 Epithelial Cell Monolayers: Role of Vacuolating Toxin VacA and cagPathogenicity Island

2000 ◽  
Vol 68 (9) ◽  
pp. 5225-5233 ◽  
Author(s):  
Véronique Hofman ◽  
Vittorio Ricci ◽  
Antoine Galmiche ◽  
Patrick Brest ◽  
Patrick Auberger ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Polymorphonuclear Leukocyte ◽  
Broth Culture ◽  
Intestinal Cell ◽  
T84 Cells ◽  
Vacuolating Cytotoxin ◽  
Intestinal Cell Line ◽  
H Pylori

ABSTRACT Helicobacter pylori infection can induce polymorphonuclear leukocyte (PMNL) infiltration of the gastric mucosa, which characterizes acute chronic gastritis. The mechanisms underlying this process are poorly documented. The lack of an in vitro model has considerably impaired the study of transepithelial migration of PMNL induced by H. pylori. In the present work, we used confluent polarized monolayers of the human intestinal cell line T84 grown on permeable filters to analyze the epithelial PMNL response induced by broth culture filtrates (BCFs) and bacterial suspensions from different strains of H. pylori. We have evaluated the role of the vacuolating cytotoxin VacA and of the cagpathogenicity island (PAI) of H. pylori in PMNL migration via their effects on T84 epithelial cells. We noted no difference in the rates of PMNL transepithelial migration after epithelial preincubation with bacterial suspensions or with BCFs of VacA-negative or VacA-positive H. pylori strains. In contrast, PMNL transepithelial migration was induced after incubation of the T84 cells with cag PAI-positive and cagE-positiveH. pylori strains. Finally, PMNL migration was correlated with a basolateral secretion of interleukin-8 by T84 cells, thus creating a subepithelial chemotactic gradient for PMNL. These data provide evidence that the vacuolating cytotoxin VacA is not involved in PMNL transepithelial migration and that the cag PAI, with a pivotal role for the cagE gene, provokes a transcellular signal across T84 monolayers, inducing a subepithelial PMNL response.

scholarly journals Houseflies Are an Unlikely Reservoir or Vector forHelicobacter pylori

1998 ◽  
Vol 36 (9) ◽  
pp. 2786-2788 ◽  
Author(s):  
Michael S. Osato ◽  
Kamran Ayub ◽  
Hong-Hahn Le ◽  
Rita Reddy ◽  
David Y. Graham
Keyword(s):  
Helicobacter Pylori ◽  
Musca Domestica ◽  
Blood Agar ◽  
Human Feces ◽  
Route Of Transmission ◽  
Pure Cultures ◽  
Horse Blood ◽  
H Pylori ◽  
Microaerobic Conditions

The route of transmission of Helicobacter pylori from individual to individual remains undefined. It has recently been reported that the domestic housefly, Musca domestica, when fed pure cultures of H. pylori, was able to harbor the organism in its midgut for up to 30 h (P. Grubel, S. Hoffman, F. K. Chong, N. A. Barstein, C. Mepani, and D. R. Cave, J. Clin. Microbiol. 35:1300–1303, 1997). Our investigation examined whether houseflies could acquire H. pylori from fresh human feces. Domestic houseflies (40 flies/group) were exposed for 24 h to feces from an H. pylori-positive volunteer, feces from an H. pylori-negative volunteer, or feces from an H. pylori-negative volunteer to which a known amount of viable H. pylori had been added. At various intervals, flies were sacrificed and the midguts were excised, homogenized, and plated in duplicate onto selective horse blood agar plates. All plates were incubated under microaerobic conditions at 37°C for 14 days. Emergent colonies presumptive of H. pylori were picked and tested biochemically to confirm the identity as H. pylori. H. pylori was not recovered from houseflies fed human feces either naturally infected or artificially infected with H. pylori. These results suggest that the domestic housefly is not a vector for transmission or a reservoir forH. pylori infection.

scholarly journals Extracellular Release of Antigenic Proteins byHelicobacter pylori

1998 ◽  
Vol 66 (6) ◽  
pp. 2984-2986 ◽  
Author(s):  
Ping Cao ◽  
Mark S. McClain ◽  
Mark H. Forsyth ◽  
Timothy L. Cover
Keyword(s):  
Helicobacter Pylori ◽  
Culture Supernatant ◽  
Genomic Library ◽  
Membrane Vesicle ◽  
Broth Culture ◽  
Vesicle Formation ◽  
Antigenic Proteins ◽  
Extracellular Release ◽  
Secretion Pathways ◽  
H Pylori

ABSTRACT Screening a Helicobacter pylori genomic library with antisera raised against H. pylori broth culture supernatant resulted in the identification of six antigens: urease, HspB, Lpp20, DnaK, MsrA, and a cysteine-rich 28-kDa protein (designated HcpA). H. pylori antigens may be released into the extracellular space by multiple mechanisms, including specific secretion pathways, autolysis, and membrane vesicle formation.

scholarly journals Helicobacter pylori Alters Exogenous Antigen Absorption and Processing in a Digestive Tract Epithelial Cell Line Model

1998 ◽  
Vol 66 (12) ◽  
pp. 5785-5791 ◽  
Author(s):  
Tamara Matysiak-Budnik ◽  
Kathleen Terpend ◽  
Sophie Alain ◽  
Marie-José Sanson le Pors ◽  
Jehan-Francois Desjeux ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Intercellular Junctions ◽  
Paracellular Pathway ◽  
Broth Culture ◽  
Epithelial Cell Line ◽  
Epithelial Barrier Function ◽  
Ussing Chambers ◽  
H Pylori ◽  
Culture Supernatants

ABSTRACT To study the influence of Helicobacter pylori on epithelial barrier function, bacteria, bacterial sonicates, or broth culture supernatants were incubated for 24 h with HT29-19A intestinal cells grown as monolayers. Subsequently, the monolayers were mounted in Ussing chambers, and electrical resistance (R), fluxes of 22Na (JNa) and14C-mannitol (JMan) (markers of the paracellular pathway), and fluxes of horseradish peroxidase (HRP) in total (J3H-HRP), intact (JHRPi), and degraded forms were measured. H. pylori did not induce any modification of the paracellular pathway (R = 148 ± 10 versus 174 ± 16 Ω · cm2; JNa = 4.16 ± 0.44 versus 3.51 ± 0.41 μEq/h · cm2; JMan = 0.081 ± 0.01 versus 0.058 ± 0.009 μmol/h · cm2), nor did it modify J3H-HRP (2,201 ± 255 versus 2,110 ± 210 ng/h · cm2 forH. pylori-infected and control cells, respectively). However, in the presence of H. pylori, we observed a significant increase in JHRPi (520 ± 146 versus 171 ± 88 ng/h · cm2). This effect was not dependent of thecag status of the strain and was not reproduced by the sonicates or the culture supernatants. It was related to the presence of urease, since a urease-negative mutant of H. pylori did not induce this effect. Ammonia and bafilomycin A1, two agents known to increase the endolysosomal pH, reproduced the increase in JHRPi. In conclusion, H. pylori does not affect directly the integrity of intercellular junctions of epithelial cells in vitro, but it increases the passage of intact HRP, probably by inhibition of the intralysosomal degradation due to the release of ammonia. The increased transport of intact macromolecules may contribute to the induction and maintenance of gastric inflammation by H. pylori.

scholarly journals Heterogeneity in Levels of Vacuolating Cytotoxin Gene (vacA) Transcription among Helicobacter pylori Strains

1998 ◽  
Vol 66 (7) ◽  
pp. 3088-3094 ◽  
Author(s):  
M. H. Forsyth ◽  
J. C. Atherton ◽  
M. J. Blaser ◽  
T. L. Cover
Keyword(s):  
Helicobacter Pylori ◽  
Broth Culture ◽  
Promoter Strength ◽  
Vacuolating Cytotoxin ◽  
H Pylori ◽  
Culture Supernatants ◽  
Different Levels ◽  
Transcriptional Fusions ◽  
Cytotoxin Gene

ABSTRACT Broth culture supernatants from Tox+ Helicobacter pylori strains induce vacuolation of HeLa cells in vitro and contain VacA in concentrations that are higher than those found in supernatants from Tox− H. pyloristrains. To investigate the basis for this phenomenon, we analyzed the transcription of the vacuolating cytotoxin gene (vacA) in eight Tox+ strains (each with a type s1/m1 vacA genotype) and nine Tox− strains (each with a type s2/m2 vacA genotype). Most of the Tox+ and Tox− strains tested used the samevacA transcriptional start point, but Tox+strains yielded significantly stronger primer extension signal intensities than did Tox− strains (mean densitometry values of 15.8 ± 1.9 versus 8.9 ± 1.7, P = 0.0016). Correspondingly, when we introducedvacA::xylE transcriptional fusions into the chromosomes of a Tox+ strain (60190) and a Tox− strain (86-313), the level of XylE activity in 60190vacA::xylE was about 30-fold higher than that in 86-313 vacA::xylE. Sequence analysis and promoter exchange experiments indicated that the different levels of vacA transcription in these two strains cannot be explained solely by a difference in promoter strength. These data indicate that Tox+ and Tox− H. pylori strains typically differ not only in the VacA amino acid sequence but also in the level of vacA transcription.

scholarly journals Effect of Cold Starvation, Acid Stress, and Nutrients on Metabolic Activity of Helicobacter pylori

2002 ◽  
Vol 68 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Hans-Olof Nilsson ◽  
Jens Blom ◽  
Waleed Abu Al-Soud ◽  
Åsa Ljungh ◽  
Leif P. Andersen ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Reverse Transcription ◽  
Disease Transmission ◽  
Broth Culture ◽  
Total Rna ◽  
Reverse Transcription Pcr ◽  
Metabolic Activities ◽  
H Pylori ◽  
Polyphosphate Granules

ABSTRACT Helicobacter pylori can transform, in vivo as well as in vitro, from dividing spiral-shaped forms into nonculturable coccoids, with intermediate forms called U forms. The importance of nonculturable coccoid forms of H. pylori in disease transmission and antibiotic treatment failures is unclear. Metabolic activities of actively growing as well as nonculturable H. pylori were investigated by comparing the concentrations of cellular ATP and total RNA, gene expression, presence of cytoplasmic polyphosphate granules and iron inclusions, and cellular morphology during extended broth culture and nutritional cold starvation. In addition, the effect of exposing broth-cultured or cold-starved cells to a nutrient-rich or acidic environment on the metabolic activities was investigated. ATP was detectable up to 14 days and for at least 25 days after transformation from the spiral form to the coccoid form or U form in broth-cultured and cold-starved cells, respectively. mRNAs of VacA, a 26-kDa protein, and urease A were detected by using reverse transcription-PCR in cells cultured for 2 months in broth or cold starved for at least 28 months. The ATP concentration was not affected during exposure to fresh or acidified broth, while 4- to 12-h exposures of nonculturable cells to lysed human erythrocytes increased cellular ATP 12- to 150-fold. Incubation of nonculturable cold-starved cells with an erythrocyte lysate increased total RNA expression and ureA mRNA transcription as measured by quantitative real-time reverse transcription-PCR. Furthermore, the number of structurally intact starved coccoids containing polyphosphate granules increased almost fourfold (P = 0.0022) under the same conditions. In conclusion, a specific environmental stimulus can induce ATP, polyphosphate, and RNA metabolism in nonculturable H. pylori, indicating viability of such morphological forms.

scholarly journals Helicobacter pylori and Helicobacter heilmannii in untreated Bulgarian children over a period of 10 years

2007 ◽  
Vol 56 (8) ◽  
pp. 1081-1085 ◽  
Author(s):  
Lyudmila Boyanova ◽  
Elena Lazarova ◽  
Christo Jelev ◽  
Galina Gergova ◽  
Ivan Mitov
Keyword(s):  
Helicobacter Pylori ◽  
Chronic Gastritis ◽  
Living Environment ◽  
Rural Children ◽  
Rapid Urease Test ◽  
Infection Prevalence ◽  
Helicobacter Heilmannii ◽  
Urease Test ◽  
H Pylori ◽  
The Impact

The aims of the study were to evaluate the incidence of Helicobacter pylori and Helicobacter heilmannii in untreated Bulgarian children from 1996 to 2006, to analyse the performance of diagnostic tests, and to look at H. pylori density in specimens by culture. Antral specimens from children with chronic gastritis (n=513), peptic ulcers (n=54) and other diseases (n=91) were evaluated by direct Gram staining (DGS), in-house rapid urease test (RUT) and culture. The living environment and semi-quantitative H. pylori density were assessed in 188 and 328 children, respectively. H. pylori infection was found in children with ulcers (77.8  %), chronic gastritis (64.5  %) and other diseases (36.3  %). Half (51.4  %) of patients aged 1–5 years and 77.4  % of those aged 16–17 years were H. pylori-positive. Of all children, 328 (49.8  %) showed positive DGS, 184 (28  %) had a positive RUT, and 386 (58.7  %) were culture-positive. Unlike gastric mucus specimens, frozen biopsy specimens provided reliable diagnosis. H. heilmannii was observed in two (0.3  %) children. High H. pylori density (growth into all quadrants of plates) was found in 18  % of 328 children evaluated, involving 31  % of ulcer and 16.7  % of non-ulcer patients. H. pylori infection was more common in rural children with chronic gastritis (91.3  %) than in the remainder (66.7  %). In conclusion, H. pylori infection was common in symptomatic Bulgarian children. The infection prevalence was >77  % in patients aged 16–17 years, in children with a duodenal ulcer, and in rural patients. H. heilmannii infection was uncommon. The performance of the bacterial culture was good. The impact of H. pylori density on the clinical expression and eradication of the infection requires further evaluation. The results highlight the need for routine H. pylori diagnosis in rural children with chronic gastritis.

scholarly journals Antimicrobial Susceptibility of Helicobacter pylori Determined by the E Test Using Tetrazolium Egg Yolk Agar

1998 ◽  
Vol 36 (9) ◽  
pp. 2784-2785 ◽  
Author(s):  
Yanet Valdez ◽  
Billie Velapatiño ◽  
Robert H. Gilman ◽  
Vilma Gutierrez ◽  
Carlos León
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Agar Medium ◽  
Egg Yolk ◽  
Blood Agar ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Agar Dilution ◽  
H Pylori

Metronidazole and tetracycline E tests were compared to an agar dilution method for the antimicrobial susceptibility testing ofHelicobacter pylori. Sixteen strains were tested by using tetrazolium egg yolk (TEY) agar. The characteristic E test inhibition ellipse was clearer on TEY agar than on standard blood agar and gave results comparable to those of the agar dilution test. The use of TEY medium is preferable to that of blood agar medium in E test MIC determinations for H. pylori.

scholarly journals Kinetics and Mechanisms of Extracellular Protein Release by Helicobacter pylori

1999 ◽  
Vol 67 (10) ◽  
pp. 5247-5252 ◽  
Author(s):  
Wayne Schraw ◽  
Mark S. McClain ◽  
Timothy L. Cover
Keyword(s):  
Helicobacter Pylori ◽  
Early Time ◽  
Medium Composition ◽  
Protein Release ◽  
Extracellular Protein ◽  
Broth Culture ◽  
Bacterial Cells ◽  
Gastric Mucus ◽  
Extracellular Release ◽  
H Pylori

ABSTRACT To investigate the kinetics and mechanisms of extracellular protein release by Helicobacter pylori, we analyzed the entry of metabolically radiolabeled bacterial proteins into broth culture supernatant. At early time points, vacuolating cytotoxin (VacA) constituted a major extracellular protein. Subsequently, culture supernatants accumulated many proteins that were components of intact bacterial cells. This nonselective release of proteins was associated with a decreasing turbidity of cultures and loss of bacterial viability, indicative of an autolytic process. The rates of VacA secretion and autolysis were each influenced by medium composition, and therefore these may be regulated phenomena. Extracellular release of proteins by H. pylori may be an important adaptation that facilitates the persistence of H. pylori in the human gastric mucus layer. Moreover, entry of proinflammatory proteins into the gastric mucosa may contribute to the induction of a mucosal inflammatory response.

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