scholarly journals Myricetin as an Antivirulence Compound Interfering with a Morphological Transformation into Coccoid Forms and Potentiating Activity of Antibiotics against Helicobacter pylori

2021 ◽  
Vol 22 (5) ◽  
pp. 2695
Author(s):  
Paweł Krzyżek ◽  
Paweł Migdał ◽  
Emil Paluch ◽  
Magdalena Karwańska ◽  
Alina Wieliczko ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Inhibitory Effect ◽  
Morphological Transformation ◽  
High Tendency ◽  
Minimal Inhibitory Concentrations ◽  
Coccoid Form ◽  
Stomach Diseases ◽  
Fold Reduction ◽  
H Pylori

Helicobacter pylori, a gastric pathogen associated with a broad range of stomach diseases, has a high tendency to become resistant to antibiotics. One of the most important factors related to therapeutic failures is its ability to change from a spiral to a coccoid form. Therefore, the main aim of our original article was to determine the influence of myricetin, a natural compound with an antivirulence action, on the morphological transformation of H. pylori and check the potential of myricetin to increase the activity of antibiotics against this pathogen. We observed that sub-minimal inhibitory concentrations (sub-MICs) of this compound have the ability to slow down the process of transformation into coccoid forms and reduce biofilm formation of this bacterium. Using checkerboard assays, we noticed that the exposure of H. pylori to sub-MICs of myricetin enabled a 4–16-fold reduction in MICs of all classically used antibiotics (amoxicillin, clarithromycin, tetracycline, metronidazole, and levofloxacin). Additionally, RT-qPCR studies of genes related to the H. pylori morphogenesis showed a decrease in their expression during exposure to myricetin. This inhibitory effect was more strongly seen for genes involved in the muropeptide monomers shortening (csd3, csd6, csd4, and amiA), suggesting their significant participation in the spiral-to-coccoid transition. To our knowledge, this is the first research showing the ability of any compound to synergistically interact with all five antibiotics against H. pylori and the first one showing the capacity of a natural substance to interfere with the morphological transition of H. pylori from spiral to coccoid forms.

scholarly journals Biofilm Formation as a Complex Result of Virulence and Adaptive Responses of Helicobacter pylori

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1062
Author(s):  
Paweł Krzyżek ◽  
Rossella Grande ◽  
Paweł Migdał ◽  
Emil Paluch ◽  
Grażyna Gościniak
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Efflux Pump ◽  
Complex Structure ◽  
Potential Contribution ◽  
Adaptive Responses ◽  
Morphological Transformation ◽  
Oral Infections ◽  
H Pylori

Helicobacter pylori is a bacterium that is capable of colonizing a host for many years, often for a lifetime. The survival in the gastric environment is enabled by the production of numerous virulence factors conditioning adhesion to the mucosa surface, acquisition of nutrients, and neutralization of the immune system activity. It is increasingly recognized, however, that the adaptive mechanisms of H. pylori in the stomach may also be linked to the ability of this pathogen to form biofilms. Initially, biofilms produced by H. pylori were strongly associated by scientists with water distribution systems and considered as a survival mechanism outside the host and a source of fecal-oral infections. In the course of the last 20 years, however, this trend has changed and now the most attention is focused on the biomedical aspect of this structure and its potential contribution to the therapeutic difficulties of H. pylori. Taking into account this fact, the aim of the current review is to discuss the phenomenon of H. pylori biofilm formation and present this mechanism as a resultant of the virulence and adaptive responses of H. pylori, including morphological transformation, membrane vesicles secretion, matrix production, efflux pump activity, and intermicrobial communication. These mechanisms will be considered in the context of transcriptomic and proteomic changes in H. pylori biofilms and their modulating effect on the development of this complex structure.

scholarly journals In Vitro Activity of Sertraline, an Antidepressant, Against Antibiotic-Susceptible and Antibiotic-Resistant Helicobacter pylori Strains

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 228 ◽  
Author(s):  
Paweł Krzyżek ◽  
Roman Franiczek ◽  
Barbara Krzyżanowska ◽  
Łukasz Łaczmański ◽  
Paweł Migdał ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Morphological Transformation ◽  
Gastric Diseases ◽  
Additive Interaction ◽  
Antibiotic Resistant ◽  
Minimal Inhibitory Concentrations ◽  
Killing Assay ◽  
H Pylori ◽  
Light Fluorescence

Antibiotic resistance of Helicobacter pylori, a spiral bacterium associated with gastric diseases, is a topic that has been intensively discussed in last decades. Recent discoveries indicate promising antimicrobial and antibiotic-potentiating properties of sertraline (SER), an antidepressant substance. The aim of the study, therefore, was to determine the antibacterial activity of SER in relation to antibiotic-sensitive and antibiotic-resistant H. pylori strains. The antimicrobial tests were performed using a diffusion-disk method, microdilution method, and time-killing assay. The interaction between SER and antibiotics (amoxicillin, clarithromycin, tetracycline, and metronidazole) was determined by using a checkerboard method. In addition, the study was expanded to include observations by light, fluorescence, and scanning electron microscopy. The growth inhibition zones were in the range of 19–37 mm for discs impregnated with 2 mg of SER. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) counted for 2–8 µg/mL and 4–8 µg/mL, respectively. The time-killing assay showed the time-dependent and concentration-dependent bactericidal activity of SER. Bacteria exposed to MBCs (but not sub-MICs and MICs ≠ MBCs) underwent morphological transformation into coccoid forms. This mechanism, however, was not protective because these cells after a 24-h incubation had a several-fold reduced green/red fluorescence ratio compared to the control. Using the checkerboard assay, a synergistic/additive interaction of SER with all four antibiotics tested was demonstrated. These results indicate that SER may be a promising anti-H. pylori compound.

The rod-to-coccoid body transformation in cultures of Helicobacter pylori

1990 ◽  
Vol 48 (3) ◽  
pp. 626-627
Author(s):  
A. R. Crooker ◽  
W. G. Kraft ◽  
T. L. Beard ◽  
M. C. Myers
Keyword(s):  
Helicobacter Pylori ◽  
Growth Cycle ◽  
Negative Bacterium ◽  
Body Formation ◽  
Coccoid Form ◽  
Spiral Form ◽  
Prolonged Culture ◽  
H Pylori ◽  
Upper Gastrointestinal

Helicobacter pylori is a microaerophilic, gram-negative bacterium found in the upper gastrointestinal tract of humans. There is strong evidence that H. pylori is important in the etiology of gastritis; the bacterium may also be a major predisposing cause of peptic ulceration. On the gastric mucosa, the organism exists as a spiral form with one to seven sheathed flagella at one (usually) or both poles. Short spirals were seen in the first successful culture of the organism in 1983. In 1984, Marshall and Warren reported a coccoid form in older cultures. Since that time, other workers have observed rod and coccal forms in vitro; coccoid forms predominate in cultures 3-7 days old. We sought to examine the growth cycle of H. pylori in prolonged culture and the mode of coccoid body formation.

scholarly journals Effects of Oral Vaccination and Immunomodulation by Cholera Toxin on Experimental Helicobacter pylori Infection, Reinfection, and Gastritis

2002 ◽  
Vol 70 (8) ◽  
pp. 4621-4627 ◽  
Author(s):  
S. Raghavan ◽  
A.-M. Svennerholm ◽  
J. Holmgren
Keyword(s):  
Helicobacter Pylori ◽  
Cholera Toxin ◽  
Mononuclear Cells ◽  
Oral Treatment ◽  
Bacterial Load ◽  
Oral Immunization ◽  
Initial Infection ◽  
Fold Reduction ◽  
H Pylori

ABSTRACT Therapeutic vaccination is an attractive strategy to control infection and disease caused by Helicobacter pylori. In mice infected with H. pylori we have studied the protective effect of oral immunization with an H. pylori lysate preparation given together with the mucosal adjuvant cholera toxin (CT), both against the initial infection and against a later reinfection challenge. We have also examined the effects of treatment with the CT adjuvant alone on H. pylori infection and reinfection. Specific immunization with lysate was found to result in a sixfold reduction of the extent (bacterial load) of the primary infection and also to provide similar levels of protection against reinfection. However, these effects were associated with severe postimmunization gastritis. In contrast, oral treatment with CT alone at the time of initial infection, while unable to suppress the initial infection, gave rise to a 20-fold reduction in bacterial load upon reinfection without causing any associated gastric inflammation. Both the infected animals that were specifically immunized and those that were treated with CT only displayed increased in vitro proliferative responses of mononuclear cells to H. pylori antigens. Antibody levels in response to H. pylori were on the other hand only marginally increased after treatment with CT, whereas they were markedly elevated after immunization with lysate plus CT, with a rise in both (Th2-driven) immunoglobulin G1 (IgG1) and, especially, (Th1-driven) IgG2a antibodies. The results illustrate the complex balance between protection and harmful inflammation after postinfection vaccination against H. pylori as studied in a mouse model.

scholarly journals Efficacy of and Resistance to Rifaximin-based Quadruple Therapy in Helicobacter pylori Eradication

2020 ◽  
Vol 20 (3) ◽  
pp. 218-224
Author(s):  
Hyun Soo Kim ◽  
Hyuk Yoon ◽  
Dong Woo Shin ◽  
Dong Jun Oh ◽  
Mingu Kwon ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Rescue Therapy ◽  
Treatment Options ◽  
Treatment Protocol ◽  
Resistance Rate ◽  
Quadruple Therapy ◽  
Minimal Inhibitory Concentrations ◽  
Intention To Treat ◽  
H Pylori ◽  
Triple Regimen

Background/Aims: The treatment options for Helicobacter pylori (<i>H. pylori</i>) infection are in a state of flux: traditional triple therapies have started to fail, and new treatments are unable to achieve optimal eradication rates. Rifaximin and rifabutin are new antibiotics. The aim of this study was to evaluate the efficacy and safety of adding rifaximin to the standard triple regimen and of a rifabutin-based triple regimen as a rescue therapy for <i>H. pylori</i> eradication.Materials and Methods: We enrolled 27 <i>H. pylori</i>-positive patients who were treated with a proton pump inhibitor, amoxicillin, clarithromycin, and rifaximin for 14 days. <i>H. pylori</i> eradication was assessed by a <sup>13</sup>C-urea breath test performed 4 weeks after therapy completion. The efficacy of the therapy was based on intention-to-treat (ITT) and per-protocol (PP) analysis. We also investigated the resistance rate, compliance, and side effects associated with rifaximin therapy. Minimal inhibitory concentrations and resistance to rifabutin were evaluated using the agar dilution method.Results: Of the 27 patients, 22 completed the treatment protocol with 100% compliance; five patients withdrew. The ITT and PP eradication rates for the rifaximin-containing quadruple therapy were 70.4% (19/27) and 86.3% (19/22), respectively. Adverse events were observed in five of 22 patients (22.7%). The resistance rates to rifaximin and rifabutin were 66.7% (2/3) and 0% (0/3), respectively.Conclusions: The findings of this study show the limitations of rifaximin-based quadruple therapy and suggest the benefits of a rifabutin-based rescue regimen in South Korea.

scholarly journals Effects of vaccination by a recombinant antigen ureB138 (a segment of the β-subunit of urease) against Helicobacter pylori infection

2007 ◽  
Vol 56 (6) ◽  
pp. 847-853 ◽  
Author(s):  
Fumiko Morihara ◽  
Ryoji Fujii ◽  
Emi Hifumi ◽  
Akira Nishizono ◽  
Taizo Uda
Keyword(s):  
Helicobacter Pylori ◽  
Mononuclear Cells ◽  
Gel Filtration ◽  
Immunohistochemical Analysis ◽  
Inhibitory Effect ◽  
Enzymic Activity ◽  
Amino Acid Sequences ◽  
Glutathione S Transferase ◽  
Important Region ◽  
H Pylori

Helicobacter pylori has to counteract acidity during colonization in the stomach. The most important region for the enzymic activity of H. pylori urease, consisting of 138 aa (ureB138), was determined by a comparison of the homology of amino acid sequences, and a structural analysis, between urease of H. pylori and various other species. This region was expressed in Escherichia coli as a fusion protein with glutathione S-transferase (GST), which was cleaved by PreScission protease between the GST moiety and ureB138. The ureB138 protein was then purified by gel filtration. The polyclonal antibody (pAb) induced by immunization with the purified ureB138 could suppress urease activity by about 50 %, while the pAb against the H. pylori urease did not show any inhibitory effect at all. Immunohistochemical analysis indicated that the ureB138-specific pAb specifically recognized the H. pylori infecting human gastric tissues. The effects of vaccination of recombinant ureB138 against infection by this organism were also examined. Specific IgG and IgA antibodies against H. pylori urease were induced in the serum of mice immunized with ureB138. A reduction in the number of colonizing H. pylori was observed in mice treated with ureB138 compared to ones treated with BSA and infection control mice. In the protected mice, severe gastritis characterized by marked infiltration of mononuclear cells was noted compared with the gastritis observed in unprotected mice. Immunohistochemical staining for IgA in gastric mucosa showed that the number of mice positively stained with IgA was significantly higher in ureB138-vaccinated mice than in non-vaccinated mice. This indicates that local IgA antibody and severe post-immunization gastritis correlate well with the protection of mice against H. pylori infection.

scholarly journals The Puzzle of Coccoid Forms of Helicobacter pylori: Beyond Basic Science

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 293
Author(s):  
Enzo Ierardi ◽  
Giuseppe Losurdo ◽  
Alessia Mileti ◽  
Rosa Paolillo ◽  
Floriana Giorgio ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Dual Therapy ◽  
Current Evidence ◽  
High Dose ◽  
Coccoid Form ◽  
High Proton ◽  
Polymerase Chain ◽  
H Pylori ◽  
One Year ◽  
Inhibitor Dose

Helicobacter pylori (H. pylori) may enter a non-replicative, non-culturable, low metabolically active state, the so-called coccoid form, to survive in extreme environmental conditions. Since coccoid forms are not susceptible to antibiotics, they could represent a cause of therapy failure even in the absence of antibiotic resistance, i.e., relapse within one year. Furthermore, coccoid forms may colonize and infect the gastric mucosa in animal models and induce specific antibodies in animals and humans. Their detection is hard, since they are not culturable. Techniques, such as electron microscopy, polymerase chain reaction, loop-mediated isothermal amplification, flow cytometry and metagenomics, are promising even if current evidence is limited. Among the options for the treatment, some strategies have been suggested, such as a very high proton pump inhibitor dose, high-dose dual therapy, N-acetycysteine, linolenic acid and vonoprazan. These clinical, diagnostic and therapeutic uncertainties will represent fascinating challenges in the future.

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 Genetic Determinants of Biofilm Formation and Antibiotic Resistance of Helicobacter Pylori using Whole Genome Sequencing

2021 ◽  
Author(s):  
Kartika Afrida Fauzia ◽  
Hafeza Aftab ◽  
Muhammad Miftahussurur ◽  
Langgeng Agung Waskito ◽  
Vo Phuoc Tuan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Cross Sectional Study ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Genetic Determinants ◽  
Genome Sequences ◽  
Cross Sectional ◽  
H Pylori

Abstract The nucleotide polymorphisms (SNPs) associated with the biofilm formation phenotype of Helicobacter pylori were investigated. Fifty-six H. pylori isolates from Bangladeshi patients were included in this cross-sectional study. Crystal violet was used to classify the phenotypes into high- and low-biofilm formers. Whole genome sequences were analyzed using the “Antimicrobial Resistance Identification By Assembly” (ARIBA) pipeline. The results indicated 19.6% high- and 81.4% low-biofilm formers. These phenotypes were not related to specific clades in the phylogenetic analysis. Biofilm formation was significantly associated with SNPs of alpA, alpB, cagE, cgt, csd4, csd5, futB, gluP, homD, and murF (P < 0.05). Among the SNPs reported in alpB, strains encoding the N156K, G160S, and A223V mutations were high-biofilm formers. Mutations associated with antibiotic resistance can be detected. This study revealed the potential role of SNPs to biofilm formation, and propose a method to detect mutation in antibiotic resistance and biofilm from whole genome sequences.

scholarly journals A peptide of a type I toxin-antitoxin system induces Helicobacter pylori morphological transformation from spiral-shape to coccoids

2019 ◽  
Author(s):  
Lamya El Mortaji ◽  
Alejandro Tejada-Arranz ◽  
Aline Rifflet ◽  
Ivo G Boneca ◽  
Gérard Pehau-Arnaudet ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Helicobacter Pylori ◽  
Membrane Integrity ◽  
Type I ◽  
Morphological Transformation ◽  
Bacterial Chromosomes ◽  
Concentration Result ◽  
H Pylori ◽  
Plasmid Stabilization

SummaryToxin-antitoxin systems are found in many bacterial chromosomes and plasmids with roles ranging from plasmid stabilization to biofilm formation and persistence. In these systems, the expression/activity of the toxin is counteracted by an antitoxin, which in type I systems is an antisense-RNA. While the regulatory mechanisms of these systems are mostly well-defined, the toxins’ biological activity and expression conditions are less understood. Here, these questions were investigated for a type I toxin-antitoxin system (AapA1-IsoA1) expressed from the chromosome of the human pathogen Helicobacter pylori. We show that expression of the AapA1 toxin in H. pylori causes growth arrest associated with rapid morphological transformation from spiral-shaped bacteria to round coccoid cells. Coccoids are observed in patients and during in vitro growth as a response to different stress conditions. The AapA1 toxin, first molecular effector of coccoids to be identified, targets H. pylori inner membrane without disrupting it, as visualized by Cryo-EM. The peptidoglycan composition of coccoids is modified with respect to spiral bacteria. No major changes in membrane potential or ATP concentration result from AapA1 expression, suggesting coccoid viability. Single-cell live microscopy tracking the shape conversion suggests a possible association of this process with cell elongation/division interference. Oxidative stress induces coccoid formation and is associated with repression of the antitoxin promoter and enhanced processing of its transcript, leading to an imbalance in favor of AapA1 toxin expression.Our data support the hypothesis of viable coccoids with characteristics of dormant bacteria that might be important in H. pylori infections refractory to treatment.Significance StatementHelicobacter pylori, a gastric pathogen causing 800,000 deaths in the world annually, is encountered both in vitro and in patients as spiral-shaped bacteria and as round cells named coccoids. We discovered that the toxin from a chromosomal type I toxin-antitoxin system is targeting H. pylori membrane and acting as an effector of H. pylori morphological conversion to coccoids. We showed that these round cells maintain their membrane integrity and metabolism, strongly suggesting that they are viable dormant bacteria. Oxidative stress was identified as a signal inducing toxin expression and coccoid formation. Our findings reveal new insights into a form of dormancy of this bacterium that might be associated with H. pylori infections refractory to treatment.

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