scholarly journals Rifampin and Rifabutin Resistance Mechanism inHelicobacter pylori

1999 ◽  
Vol 43 (6) ◽  
pp. 1497-1499 ◽  
Author(s):  
Markus Heep ◽  
Daniela Beck ◽  
Ekkehard Bayerdörffer ◽  
Norbert Lehn
Keyword(s):  
Escherichia Coli ◽  
Helicobacter Pylori ◽  
Mycobacterium Tuberculosis ◽  
Amino Acid ◽  
Resistance Mechanism ◽  
Clinical Isolates ◽  
Gene Sequences ◽  
H Pylori

ABSTRACT Eighty-one clinical isolates of Helicobacter pylorishowed no resistance to rifampin (MIC range, 0.032 to 2 μg/ml; MIC at which 50% of isolates are inhibited [MIC50], 0.25 μg/ml). The MIC50 of rifabutin was 0.008 μg/ml (n = 16). All resistant laboratory mutants of H. pylori ATCC 43504 showed amino acid exchanges in codons 524 to 545 or codon 585 of the rpoB gene, corresponding to the gene sequences from Mycobacterium tuberculosis andEscherichia coli.

scholarly journals Alterations in Penicillin-Binding Protein 1A Confer Resistance to β-Lactam Antibiotics in Helicobacter pylori

2002 ◽  
Vol 46 (7) ◽  
pp. 2229-2233 ◽  
Author(s):  
M. M. Gerrits ◽  
D. Schuijffel ◽  
A. A. van Zwet ◽  
E. J. Kuipers ◽  
C. M. J. E. Vandenbroucke-Grauls ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Binding Protein ◽  
Resistance Mechanism ◽  
Fold Increase ◽  
Single Amino Acid ◽  
Penicillin Binding Protein ◽  
H Pylori ◽  
High Level

ABSTRACT Most Helicobacter pylori strains are susceptible to amoxicillin, an important component of combination therapies for H. pylori eradication. The isolation and initial characterization of the first reported stable amoxicillin-resistant clinical H. pylori isolate (the Hardenberg strain) have been published previously, but the underlying resistance mechanism was not described. Here we present evidence that the β-lactam resistance of the Hardenberg strain results from a single amino acid substitution in HP0597, a penicillin-binding protein 1A (PBP1A) homolog of Escherichia coli. Replacement of the wild-type HP0597 (pbp1A) gene of the amoxicillin-sensitive (Amxs) H. pylori strain 1061 by the Hardenberg pbp1A gene resulted in a 100-fold increase in the MIC of amoxicillin. Sequence analysis of pbp1A of the Hardenberg strain, the Amxs H. pylori strain 1061, and four amoxicillin-resistant (Amxr) 1061 transformants revealed a few amino acid substitutions, of which only a single Ser414→Arg substitution was involved in amoxicillin resistance. Although we cannot exclude that mutations in other genes are required for high-level amoxicillin resistance of the Hardenberg strain, this amino acid substitution in PBP1A resulted in an increased MIC of amoxicillin that was almost identical to that for the original Hardenberg strain.

scholarly journals Diversity of 3′ variable region of cagA gene in Helicobacter pylori strains isolated from Chinese population

Gut Pathogens ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhijing Xue ◽  
Yuanhai You ◽  
Lihua He ◽  
Yanan Gong ◽  
Lu Sun ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Amino Acid ◽  
Chinese Population ◽  
Statistical Difference ◽  
Variable Region ◽  
Repeat Region ◽  
Geographical Regions ◽  
H Pylori ◽  
Epiya Motifs

Abstract Background The cytotoxin-associated gene A (cagA) is one of the most important virulence factors of Helicobacter pylori (H. pylori). There is a highly polymorphic Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region in the C-terminal of CagA protein. This repeat region is thought to play an important role in the pathogenesis of gastrointestinal diseases. The aim of this study was to investigate the diversity of cagA 3′ variable region and the amino acid polymorphisms in the EPIYA segments of the CagA C-terminal region of H. pylori, and their association with gastroduodenal diseases. Methods A total of 515 H. pylori strains from patients in 14 different geographical regions of China were collected. The genomic DNA from each strain was extracted and the cagA 3′ variable region was amplified by polymerase chain reaction (PCR). The PCR products were sequenced and analyzed using MEGA 7.0 software. Results A total of 503 (97.7%) H. pylori strains were cagA-positive and 1,587 EPIYA motifs were identified, including 12 types of EPIYA or EPIYA-like sequences. In addition to the four reported major segments, several rare segments (e.g., B′, B″ and D′) were defined and 20 different sequence types (e.g., ABD, ABC) were found in our study. A total of 481 (95.6%) strains carried the East Asian type CagA, and the ABD subtypes were most prevalent (82.1%). Only 22 strains carried the Western type CagA, which included AC, ABC, ABCC and ABCCCC subtypes. The CagA-ABD subtype had statistical difference in different geographical regions (P = 0.006). There were seven amino acid polymorphisms in the sequences surrounding the EPIYA motifs, among which amino acids 893 and 894 had a statistical difference with gastric cancer (P = 0.004). Conclusions In this study, 503 CagA sequences were studied and analyzed in depth. In Chinese population, most H. pylori strains were of the CagA-ABD subtype and its presence was associated with gastroduodenal diseases. Amino acid polymorphisms at residues 893 and 894 flanking the EPIYA motifs had a statistically significant association with gastric cancer.

scholarly journals Furazolidone- and Nitrofurantoin-ResistantHelicobacter pylori: Prevalence and Role of Genes Involved in Metronidazole Resistance

2001 ◽  
Vol 45 (1) ◽  
pp. 306-308 ◽  
Author(s):  
Dong H. Kwon ◽  
Miae Lee ◽  
J. J. Kim ◽  
J. G. Kim ◽  
F. A. K. El-Zaatari ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Clinical Isolates ◽  
Metronidazole Resistance ◽  
H Pylori

ABSTRACT The prevalence of furazolidone, nitrofurantoin, and metronidazole resistance among Helicobacter pylori strains was assessed with 431 clinical isolates. Fifty-two percent were metronidazole resistant, compared to 2% (7 of 431) with resistance to furazolidone and nitrofurantoin. All seven furazolidone- and nitrofurantoin-resistant isolates were also metronidazole resistant.rdxA, frxA, and fdxB knockouts did not result in furazolidone or nitrofurantoin resistance. These data suggest that furazolidone and nitrofurantoin may be good alternatives to metronidazole for treating H. pylori infection.

scholarly journals Genetic Diversity of the cagA gene of Helicobacter pylori strains from Sudanese Patients with Different Gastroduodenal Diseases

2019 ◽  
Author(s):  
Hadeel Gassim Hassan ◽  
Abeer Babiker Idris ◽  
Mohamed A. Hassan ◽  
Hisham N. Altayb ◽  
Kyakonye Yasin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Novel Mutation ◽  
Amino Acid Residues ◽  
Specific Amino Acid ◽  
Gastrointestinal Malignancy ◽  
High Incidence ◽  
H Pylori ◽  
High Level ◽  
Chloride Method

AbstractBackgroundThere is an increase in the prevalence of Helicobacter pylori infection in Sudan, accompanied by a high incidence of upper gastrointestinal malignancy. The cytotoxin-associated gene cagA gene is a marker of a pathogenicity island (PAI) in H. pylori and plays a crucial role in determining the clinical outcome of Helicobacter infections.ObjectiveThis study aimed to determine the frequency and heterogeneity of the cagA gene of H. pylori and correlate the presence of cagA gene with clinical outcomes.Materials and methodsFifty endoscopy biopsies were collected from Fedail and Soba hospitals in Khartoum state. DNA was extracted using the Guanidine chloride method followed by PCR to amplify 16S rRNA and cagA gene of H. pylori using specific primers. DNA amplicons of cagA gene were purified and sequenced. Bioinformatics and statistical analysis were done to characterize and to test the association between cagA gene and gastric complications.ResultsCagA gene was detected in 20/37(54%) of the samples that were found positive for H. pylori. There was no association between endoscopy finding and the presence of the cagA gene (p = 0.225). Specific amino acid variations were found at seven loci related to strains from a patient with duodenitis, gastric ulcer, and gastric atrophy (R448H, T457K, S460L, IT463-464VA, D470E, A482Q, KNV490-491-492TKT) while mutations in cancerous strain were A439P, T457P, and H500Y.ConclusionDisease-specific variations of cagA of H. pylori strains, in the region of amino acid residues 428-510, were evident among Sudanese patients with different gastroduodenal diseases. A novel mutation (K458N) was detected in a patient with duodenitis, which affects the positive electrostatic surface of cagA. Phylogenetic analysis showed a high level of diversity of cagA from Sudanese H. pylori strains.

scholarly journals Diversity of 3’ variable region of cagA gene in Helicobacter pylori strains isolated from Chinese population

2021 ◽  
Author(s):  
Zhijing Xue ◽  
Yuanhai You ◽  
Lihua He ◽  
Yanan Gong ◽  
Lu Sun ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Amino Acid ◽  
Chinese Population ◽  
Statistical Difference ◽  
Variable Region ◽  
Repeat Region ◽  
Geographical Regions ◽  
H Pylori ◽  
Epiya Motifs

Abstract Background: The cytotoxin-associated gene A (cagA) is one of the most important virulence factors of Helicobacter pylori (H. pylori). There is a highly polymorphic Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region in the C-terminal of CagA protein. This repeat region is thought to play an important role in the pathogenesis of gastrointestinal diseases. The aim of this study was to investigate the diversity of cagA 3’ variable region and the amino acid polymorphisms in the EPIYA segments of the CagA C-terminal region of H. pylori, and their association with gastroduodenal diseases.Methods: A total of 515 H. pylori strains from patients in 14 different geographical regions of China were collected. The genomic DNA from each strain was extracted and the cagA 3’ variable region was amplified by polymerase chain reaction (PCR). The PCR products were sequenced and analyzed using MEGA 7.0 software.Results: A total of 503 (97.7%) H. pylori strains were cagA-positive and 1,587 EPIYA motifs were identified, including 12 types of EPIYA or EPIYA-like sequences. In addition to the four reported major segments, several rare segments (e.g., B’, B’’ and D’) were defined and 20 different sequence types (e.g., ABD, ABC) were found in our study. A total of 481 (95.6%) strains carried the East Asian type CagA, and the ABD subtypes were most prevalent (82.1%). Only 22 strains carried the Western type CagA, which include AC, ABC, ABCC and ABCCCC subtypes. The CagA-ABD subtype had statistical difference in different geographic regions (P = 0.006). There are seven amino acid polymorphisms in the sequences surrounding the EPIYA motifs, among which amino acid residue 893 and 894 had a statistical difference with gastric cancer (P = 0.004).Conclusions: In this study, 503 CagA sequences was studied and analyzed in depth. In Chinese population, most H. pylori strains are of the CagA-ABD subtype and its presence was associated with gastroduodenal diseases. Amino acid polymorphisms at residue 893 and 894 flanking the EPIYA motif had a statistically significant association with gastric cancer.

scholarly journals Dynamics of Lewis b Binding and Sequence Variation of the babA Adhesin Gene during Chronic Helicobacter pylori Infection in Humans

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Sandra Nell ◽  
Lynn Kennemann ◽  
Sandra Schwarz ◽  
Christine Josenhans ◽  
Sebastian Suerbaum
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Outer Membrane ◽  
Chronic Infection ◽  
Human Infection ◽  
Complete Loss ◽  
Blood Group Antigen ◽  
Content Type ◽  
Strain Pair ◽  
H Pylori

ABSTRACTHelicobacter pyloriundergoes rapid microevolution during chronic infection, but very little is known about how this affects host interaction factors. The best-studied adhesin ofH. pyloriis BabA, which mediates binding to the blood group antigen Lewis b [Le(b)]. To study the dynamics of Le(b) adherence during human infection, we analyzed pairedH. pyloriisolates obtained sequentially from chronically infected individuals. A complete loss or significant reduction of Le(b) binding was observed in strains from 5 out of 23 individuals, indicating that the Le(b) binding phenotype is quite stable during chronic human infection. Sequence comparisons ofbabAidentified differences due to mutation and/or recombination in 12 out of 16 strain pairs analyzed. Most amino acid changes were found in the putative N-terminal extracellular adhesion domain. One strain pair that had changed from a Le(b) binding to a nonbinding phenotype was used to study the role of distinct sequence changes in Le(b) binding. By transformations of the nonbinding strain with ababAgene amplified from the binding strain,H. pyloristrains with mosaicbabAgenes were generated. Recombinants were enriched for a gain of Le(b) binding by biopanning or for BabA expression on the bacterial surface by pulldown assay. With this approach, we identified several amino acid residues affecting the strength of Le(b) binding. Additionally, the data showed that the C terminus of BabA, which is predicted to encode an outer membrane β-barrel domain, plays an essential role in the biogenesis of this protein.IMPORTANCEHelicobacter pyloricauses a chronic infection of the human stomach that can lead to ulcers and cancer. The bacterium can bind to gastric epithelial cells with specialized outer membrane proteins. The best-studied protein is the BabA adhesin which binds to the Lewis b blood group antigen. SinceH. pyloriis a bacterium with very high genetic variability, we asked whetherbabAevolves during chronic infection and how mutations or recombination inbabAaffect binding. We found that BabA-mediated adherence was stable in most individuals but observed a complete loss of binding or reduced binding in 22% of individuals. One strain pair in which binding was lost was used to generatebabAsequences that were mosaics of a functional allele and a nonfunctional allele, and the mosaic sequences were used to identify amino acids critically involved in binding of BabA to Lewis b.

scholarly journals Antibacterial Activity of Geraniol in Combination with Standard Antibiotics against Staphylococcus aureus, Escherichia coli and Helicobacter pylori

2018 ◽  
Vol 13 (7) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Subrat Kumar Bhattamisra ◽  
Chew Hui Kuean ◽  
Lee Boon Chieh ◽  
Vivian Lee Yean Yan ◽  
Chin Koh Lee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Helicobacter Pylori ◽  
Antibacterial Activity ◽  
Synergistic Effect ◽  
Inhibitory Concentration ◽  
Therapeutic Potential ◽  
E Coli ◽  
Checkerboard Assay ◽  
H Pylori

The antibacterial activity of geraniol and its effect in combination with ampicillin, amoxicillin and clarithromycin against Staphylococcus aureus, Escherichia coli and Helicobacter pylori was tested. The minimum inhibitory concentrations (MICs) and combinatory effects of geraniol against the bacteria were assessed by using the modified broth microdilution and checkerboard assay, respectively. The combinatory effect is expressed as fractional inhibitory concentration index (FICI). The MIC of geraniol against S. aureus, E. coli and H. pylori was found to be 11200, 5600, and 7325 μg/mL, respectively. A significant synergistic effect was observed with geraniol and ampicillin against S. aureus with FICI in the range 0.19 to 0.32. Geraniol and ampicillin exhibited a partial synergistic effect against E. coli. A similar effect was observed with geraniol and clarithromycin against S. aureus. A partial synergistic effect was observed with clarithromycin and geraniol against H. pylori with the FICI value in the range 0.86 to 0.89. An additive effect was observed with geraniol and amoxicillin combination against H. pylori. However, the amoxicillin and clarithromycin dose was reduced by thirty-two fold when combined with geraniol against H. pylori. The anti- H. pylori effect of geraniol with clarithromycin and amoxicillin could be of potential interest in the treatment of H. pylori infection and associated ulcers in humans. Further, geraniol, in combination with other antibiotics, has substantial therapeutic potential against S. aureus and E.coli infection.

scholarly journals Purification of Helicobacter pylori NCTC 11637 Cytochrome bc1 and Respiration with d-Proline as a Substrate

2009 ◽  
Vol 192 (5) ◽  
pp. 1410-1415 ◽  
Author(s):  
Minoru Tanigawa ◽  
Tomomitsu Shinohara ◽  
Katsushi Nishimura ◽  
Kumiko Nagata ◽  
Morio Ishizuka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Gene Clusters ◽  
Acid Dehydrogenase ◽  
Amino Acid Dehydrogenase ◽  
Transport Chain ◽  
H Pylori

ABSTRACT Helicobacter pylori is a microaerophilic bacterium associated with gastric inflammation and peptic ulcers. Knowledge of how pathogenic organisms produce energy is important from a therapeutic point of view. We found d-amino acid dehydrogenase-mediated electron transport from d-proline or d-alanine to oxygen via the respiratory chain in H. pylori. Coupling of the electron transport to ATP synthesis was confirmed by using uncoupler reagents. We reconstituted the electron transport chain to demonstrate the electron flow from the d-amino acids to oxygen using the recombinant cytochrome bc 1 complex, cytochrome c-553, and the terminal oxidase cytochrome cbb 3 complex. Upon addition of the recombinant d-amino acid dehydrogenase and d-proline or d-alanine to the reconstituted electron transport system, reduction of cytochrome cbb 3 and oxygen consumption was revealed spectrophotometrically and polarographically, respectively. Among the constituents of H. pylori's electron transport chain, only the cytochrome bc 1 complex had been remained unpurified. Therefore, we cloned and sequenced the H. pylori NCTC 11637 cytochrome bc 1 gene clusters encoding Rieske Fe-S protein, cytochrome b, and cytochrome c 1, with calculated molecular masses of 18 kDa, 47 kDa, and 32 kDa, respectively, and purified the recombinant monomeric protein complex with a molecular mass of 110 kDa by gel filtration. The absorption spectrum of the recombinant cytochrome bc 1 complex showed an α peak at 561 nm with a shoulder at 552 nm.

scholarly journals Biofilm Formation and Antibiotic Resistance Phenotype of Helicobacter pylori Clinical Isolates

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 473 ◽  
Author(s):  
Kartika Afrida Fauzia ◽  
Muhammad Miftahussurur ◽  
Ari Fahrial Syam ◽  
Langgeng Agung Waskito ◽  
Dalla Doohan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Crystal Violet ◽  
Antibiotic Susceptibility ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Resistance Phenotype ◽  
Resistance To Antibiotics ◽  
Inhibition Concentration ◽  
H Pylori

We evaluated biofilm formation of clinical Helicobacter pylori isolates from Indonesia and its relation to antibiotic resistance. We determined the minimum inhibition concentration (MIC) of amoxicillin, clarithromycin, levofloxacin, metronidazole and tetracycline by the Etest to measure the planktonic susceptibility of 101 H. pylori strains. Biofilms were quantified by the crystal violet method. The minimum biofilm eradication concentration (MBEC) was obtained by measuring the survival of bacteria in a biofilm after exposure to antibiotics. The majority of the strains formed a biofilm (93.1% (94/101)), including weak (75.5%) and strong (24.5%) biofilm-formers. Planktonic resistant and sensitive strains produced relatively equal amounts of biofilms. The resistance proportion, shown by the MBEC measurement, was higher in the strong biofilm group for all antibiotics compared to the weak biofilm group, especially for clarithromycin (p = 0.002). Several cases showed sensitivity by the MIC measurement, but resistance according to the MBEC measurements (amoxicillin, 47.6%; tetracycline, 57.1%; clarithromycin, 19.0%; levofloxacin, 38.1%; and metronidazole 38.1%). Thus, biofilm formation may increase the survival of H. pylori and its resistance to antibiotics. Biofilm-related antibiotic resistance should be evaluated with antibiotic susceptibility.

scholarly journals Anti-Helicobacter pylori Activity of the Methanolic Extract of Geum iranicum and its Main Compounds

2012 ◽  
Vol 67 (3-4) ◽  
pp. 172-180 ◽  
Author(s):  
Somayeh Shahani ◽  
Hamid R. Monsef-Esfahani ◽  
Soodabeh Saeidnia ◽  
Parastoo Saniee ◽  
Farideh Siavoshi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Phenolic Glycoside ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Aqueous Fraction ◽  
Gram Negative ◽  
Effective Fraction ◽  
H Pylori

Geum iranicum Khatamsaz, belonging to the Rosaceae family, is an endemic plant of Iran. The methanol extract of the roots of this plant showed signifi cant activity against one of the clinical isolates of Helicobacter pylori which was resistant to metronidazole. The aim of this study was the isolation and evaluation of the major compounds of G. iranicum effective against H. pylori. The compounds were isolated using various chromatographic methods and identifi ed by spectroscopic data (1H and 13C NMR, HMQC, HMBC, EI-MS). An antimicrobial susceptibility test was performed employing the disk diffusion method against clinical isolates of H. pylori and a micro dilution method against several Gram-positive and Gram-negative bacteria; additionally the inhibition zone diameters (IZD) and minimum inhibitory concentrations (MIC) values were recorded. Nine compounds were isolated: two triterpenoids, uvaol and niga-ichigoside F1, three sterols, β-sitosterol, β-sitosteryl acetate, and β-sitosteryl linoleate, one phenyl propanoid, eugenol, one phenolic glycoside, gein, one fl avanol, (+)-catechin, and sucrose. The aqueous fraction, obtained by partitioning the MeOH extract with water and chloroform, was the most effective fraction of the extract against all clinical isolates of H. pylori. Further investigation of the isolated compounds showed that eugenol was effective against H. pylori but gein, diglycosidic eugenol, did not exhibit any activity against H. pylori. The subfraction D4 was the effective fraction which contained tannins. It appeared that tannins were probably the active compounds responsible for the anti-H. pylori activity of G. iranicum. The aqueous fraction showed a moderate inhibitory activity against both Gram-positive and Gram-negative bacteria. The MIC values indicated that Gram-positive bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis are more susceptible than Gram-neagative bacteria including Escherichia coli and Pseudomonas aeruginosa.

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