SpoT-mediated NapA upregulation promotes oxidative stress-induced Helicobacter pylori biofilm formation and confers multidrug resistance

Pathogenicity and virulence of Helicobacter pylori: A paradigm of chronic infection

Infection with Helicobacter pylori is one of the most common infections of mankind. Infection typically occurs in childhood and persists for the lifetime of the host unless eradicated with antimicrobials. The organism colonizes the stomach and causes gastritis. Most infected individuals are asymptomatic, but infection also causes gastric and duodenal ulceration, and gastric cancer. H. pylori possesses an arsenal of virulence factors, including a potent urease enzyme for protection from acid, flagella that mediate motility, an abundance of outer membrane proteins that can mediate attachment, several immunomodulatory proteins, and an ability to adapt to specific conditions in individual human stomachs. The presence of a type 4 secretion system that injects effector molecules into gastric cells and subverts host cell signalling is associated with virulence. In this review we discuss the interplay of H. pylori colonization and virulence factors with host and environmental factors to determine disease outcome in infected individuals.

Nanomaterials: A Prospective Strategy for Biofilm-Forming Helicobacter pylori Treatment

Helicobacter pylori (H. pylori) is prevalent in over 50% of the global population and is recognized as the primary etiological agent for the development of gastric cancer. With the increasing incidence of antibiotic resistance, clinical treatment of H. pylori is a significant challenge. The formation of H. pylori biofilm is an important reason for antibiotic resistance and chronic infection, and it is also one of the key obstacles to eradicating H. pylori. H. pylori biofilm acts as a physical barrier, preventing the penetration of antibiotics and increasing the expression of efflux pump genes and drug-resistant gene mutations. Therefore, the treatment of H. pylori biofilm is extremely challenging. Nanomaterials, such as inorganic nanoparticles, lipid-based nanoparticles, and polymeric nanoparticles, which have properties including disrupting bacterial cell membranes, controlling drug release, and overcoming antibiotic resistance, have attracted significant interest. Furthermore, nanomaterials have the ability to treat H. pylori biofilm owing to their unique size, structure, and physical properties, including the inhibition of biofilm formation, enhancement of biofilm permeability, and disruption of mature biofilm. Moreover, nanomaterials have targeting functions and can carry antimicrobial drugs that play a synergistic role, thus providing a prospective strategy for treating H. pylori biofilm. In this review, we summarize the formation and antibiotic-resistance mechanisms of H. pylori biofilm and outline the latest progress in nanomaterials against H. pylori biofilm with the aim of laying the foundation for the development and clinical application of nanomaterials for anti-H. pylori biofilm.

Infection of Helicobacter pylori contributes to the progression of gastric cancer through ferroptosis

Helicobacter pylori (H. pylori) is a gram-negative pathogen that colonizes gastric epithelial cells, and its chronic infection is the primary risk factor for the development of gastric cancer (GC). Ferroptosis is an iron-dependent form of cell death characterized by intracellular lipid peroxide accumulation and reactive oxygen species (ROS) imbalance. There is evidence suggesting that pathogens can manipulate ferroptosis to facilitate their replication, transmission, and pathogenesis. However, the interaction between ferroptosis and H. pylori infection requires further elucidation. We reviewed the mechanism of ferroptosis and found that H. pylori virulence factors such as cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), neutrophil-activating protein A (NapA), superoxide dismutase B (SodB), γ-glutamyl transpeptidase (gGT), lipopolysaccharide (LPS), and outer inflammatory protein A (OipA) affected glutathione (GSH), ROS, and lipid oxidation to regulate ferroptosis. It also affected the progression of GC by regulating ferroptosis-related indicators through abnormal gene expression after H. pylori infected gastric mucosa cells. Finally, we discuss the potential application value of ferroptosis inducers, inhibitors and other drugs in treating H. pylori-infected GC patients while acknowledging that their interactions are still not fully understood.

Subinhibitory concentrations of antibiotics affect development and parameters of Helicobacter pylori biofilm

Introduction

Helicobacter pylori causes chronic gastric diseases in nearly 50% of people around the world. It is suggested that biofilm formation has a pronounced effect on the dynamic resistance spread and recurrence of these infections.

Methods

To mimic the scenario of therapeutic ineffectiveness, we investigated the impact of sub-minimal inhibitory concentrations (sub-MICs) of antibiotics on the development and parameters of biofilms produced by clinical H. pylori strains.

Results

We observed that constant exposure of planktonic forms to metronidazole or levofloxacin stimulated the speed of autoaggregation and the amount of extracellular matrix, resulting in increased dimensions of the developed biofilms. Contrary to this, continuous exposure to clarithromycin negatively affected a number of biofilm-related reactions and led to the biofilm-weakening effect. Through assessing the membrane fatty acid profiles of antibiotic-exposed cells, we confirmed that metronidazole and levofloxacin induced a biofilm-like phenotype, while clarithromycin kept bacteria in a planktonic form.

Discussion

Our results suggest that sub-MICs of antibiotics affect the biochemical and biophysical properties of the developing biofilm of H. pylori strains and may impact the effectiveness of antibiotic treatment.

High salt condition alters LPS synthesis and induces the emergence of drug resistance mutations in Helicobacter pylori

The burgeoning emergence of drug-resistant Helicobacter pylori strains poses a significant challenge to the clinical success of eradication therapies and is primarily attributed to mutations within drug-targeting genes that lead to antibiotic resistance. This study investigated the effect of high salt conditions on the occurrence of drug-resistance mutations in H. pylori. We found that high salt condition significantly amplifies the frequency of drug resistance mutations in H. pylori. This can be chiefly attributed to our discovery indicating that high salt concentration results in elevated reactive oxygen species (ROS) levels, initiating DNA damage within H. pylori. Mechanistically, high salt condition suppresses lipopolysaccharide (LPS) synthesis gene expression, inducing alterations in the LPS structure and escalating outer membrane permeability. This disruption of LPS synthesis attenuates the expression and activity of SodB, facilitates increased ROS levels, and consequently increases the drug resistance mutation frequency. Impairing LPS synthesis engenders a reduction in intracellular iron levels, leading to diminished holo-Fur activity and increased apo-Fur activity, which represses the expression of SodB directly. Our findings suggest a correlation between high salt intake and the emergence of drug resistance in the human pathogen H. pylori, implying that dietary choices affect the risk of emergence of antimicrobial resistance.IMPORTANCEDrug resistance mutations mainly contribute to the emergence of clinical antibiotic-resistant Helicobacter pylori, a bacterium linked to stomach ulcers and cancer. In this study, we explored how elevated salt conditions influence the emergence of drug resistance in H. pylori. We demonstrate that H. pylori exhibits an increased antibiotic resistance mutation frequency when exposed to a high salt environment. We observed an increase in reactive oxygen species (ROS) under high salt conditions, which can cause DNA damage and potentially lead to mutations. Moreover, our results showed that high salt condition alters the bacterium's lipopolysaccharide (LPS) synthesis, leading to a reduced expression of SodB in a Fur-dependent manner. This reduction, in turn, elevates ROS levels, culminating in a higher frequency of drug-resistance mutations. Our research underscores the critical need to consider environmental influences, such as diet and lifestyle, in managing bacterial infections and combating the growing challenge of antibiotic resistance.

Opportunities for Helicobacter pylori Eradication beyond Conventional Antibiotics

Helicobacter pylori (H. pylori) is a bacterium known to be associated with a significant risk of gastric cancer in addition to chronic gastritis, peptic ulcer, and MALT lymphoma. Although only a small percentage of patients infected with H. pylori develop gastric cancer, Gastric cancer causes more than 750,000 deaths worldwide, with 90% of cases being caused by H. pylori. The eradication of this bacterium rests on multiple drug regimens as guided by various consensus. However, the efficacy of empirical therapy is decreasing due to antimicrobial resistance. In addition, biofilm formation complicates eradication. As the search for new antibiotics lags behind the bacterium's ability to mutate, studies have been directed toward finding new anti-H. pylori agents while also optimizing current drug functions. Targeting biofilm, repurposing outer membrane vesicles that were initially a virulence factor of the bacteria, phage therapy, probiotics, and the construction of nanoparticles might be able to complement or even be alternatives for H. pylori treatment. This review aims to present reports on various compounds, either new or combined with current antibiotics, and their pathways to counteract H. pylori resistance.

Enhanced fatty acid biosynthesis by Sigma28 in stringent responses contributes to multidrug resistance and biofilm formation in Helicobacter pylori

The metabolic state of bacteria significantly contributes to their resistance to antibiotics; however, the specific metabolic mechanisms conferring antimicrobial resistance in Helicobacter pylori remain largely understudied. Employing transcriptomic and non-targeted metabolomics, we characterized the metabolic reprogramming of H. pylori when challenged with antibiotic agents. We observed a notable increase in both genetic and key proteomic components involved in fatty acid biosynthesis. Inhibition of this pathway significantly enhanced the antibiotic susceptibility of the sensitive and multidrug-resistant H. pylori strains while also disrupting their biofilm-forming capacities. Further analysis revealed that antibiotic treatment induced a stringent response, triggering the expression of the hp0560-hp0557 operon regulated by Sigma28 (σ28). This activation in turn stimulated the fatty acid biosynthetic pathway, thereby enhancing the antibiotic tolerance of H. pylori. Our findings reveal a novel adaptive strategy employed by H. pylori to withstand antibiotic stress.

Association between dietary niacin intake and Helicobacter pylori seropositivity in US adults: A cross-sectional study

OBJECTIVES

This study delves into the association between dietary niacin intake and Helicobacter pylori seropositivity, a topic gaining prominence in academic discourse. However, the precise role of Niacin in the development and progression of Helicobacter pylori seropositivity remains inadequately understood. Thus, this research aims to investigate the connections between H. pylori seropositivity and dietary niacin intake using a nationally representative sample of adults.

METHODS

A cross-sectional analysis encompassed 4,000 participants from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States between 1999 and 2000, all aged 20 years or older. The study employed the generalized additive model (GAM) and multivariate logistic regression to explore the potential relationship between niacin intake and Helicobacter pylori seropositivity. Subgroup analyses were performed based on gender, age, diabetes, hypertension, and hyperlipemia.

RESULTS

Analyzing cross-sectional data from NHANES 1999-2000 involving individuals aged 20 years and above revealed that out of 4,000 participants, 1,842 tested positive for H. pylori via serology. Multivariate analyses unveiled a significant inverse correlation between niacin intake and H. pylori seropositivity. Adjusted odds ratios (ORs) for dietary niacin intake in quartiles Q2 (13.31-19.26 mg/d), Q3 (19.27-27.42 mg/d), and Q4 (>27.42 mg/d) compared to Q1 (<13.31 mg/d) were 0.83 (95% CI: 0.69-1.01), 0.74 (95% CI: 0.61-0.90), and 0.66 (95% CI: 0.54-0.81), respectively. Moreover, a nonlinear L-shaped relationship (P = 0.022) emerged between niacin intake and H. pylori seropositivity, indicating minimal risk of H. pylori infection at approximately 44.69 mg of niacin per day in the diet.

CONCLUSION

This study suggests a potential link between increased dietary niacin intake and reduced prevalence of Helicobacter pylori seropositivity. This correlation is bolstered by plausible mechanisms involving immunomodulatory function, mitochondrial dysfunction, and cellular oxidative stress.

Effect and mechanism of Qingre Huashi decoction on drug-resistant Helicobacter pylori

BACKGROUND

Helicobacter pylori (HP), the most common pathogenic microorganism in the stomach, can induce inflammatory reactions in the gastric mucosa, causing chronic gastritis and even gastric cancer. HP infection affects over 4.4 billion people globally, with a worldwide infection rate of up to 50%. The multidrug resistance of HP poses a serious challenge to eradication. It has been de-monstrated that compared to bismuth quadruple therapy, Qingre Huashi decoction (QHD) combined with triple therapy exhibits comparable eradication rates but with a lower incidence of adverse reactions; in addition, QHD can directly inhibit and kill HP in vitro.

AIM

To explore the effect and mechanism of QHD on clinically multidrug-resistant and strong biofilm-forming HP.

METHODS

In this study, 12 HP strains were isolated in vitro after biopsy during gastroscopy of HP-infected patients. In vitro, the minimum inhibitory concentration (MIC) values for clinical HP strains and biofilm quantification were determined through the E-test method and crystal violet staining, respectively. The most robust biofilm-forming strain of HP was selected, and QHD was evaluated for its inhibitory and bactericidal effects on the strain with strong biofilm formation. This assessment was performed using agar dilution, E-test, killing dynamics, and transmission electron microscopy (TEM). The study also explored the impact of QHD on antibiotic resistance in these HP strains with strong biofilm formation. Crystalline violet method, scanning electron microscopy, laser confocal scanning microscopy, and (p)ppGpp chromatographic identification were employed to evaluate the effect of QHD on biofilm in strong biofilm-forming HP strains. The effect of QHD on biofilm and efflux pump-related gene expression was evaluated by quantitative polymerase chain reaction. Non-targeted metabolomics with UHPLC-MS/MS was used to identify potential metabolic pathways and biomarkers which were different between the NC and QHD groups.

RESULTS

HP could form biofilms of different degrees in vitro, and the intensity of formation was associated with the drug resistance of the strain. QHD had strong bacteriostatic and bactericidal effects on HP, with MICs of 32-64 mg/mL. QHD could inhibit the biofilm formation of the strong biofilm-forming HP strains, disrupt the biofilm structure, lower the accumulation of (p)ppGpp, decrease the expression of biofilm-related genes including LuxS, Spot, glup (HP1174), NapA, and CagE, and reduce the expression of efflux pump-related genes such as HP0605, HP0971, HP1327, and HP1489. Based on metabolomic analysis, QHD induced oxidative stress in HP, enhanced metabolism, and potentially inhibited relevant signaling pathways by upregulating adenosine monophosphate (AMP), thereby affecting HP growth, metabolism, and protein synthesis.

CONCLUSION

QHD exerts bacteriostatic and bactericidal effects on HP, and reduces HP drug resistance by inhibiting HP biofilm formation, destroying its biofilm structure, inhibiting the expression of biofilm-related genes and efflux pump-related genes, enhancing HP metabolism, and activating AMP in HP.

Proteomic Characterization of a Lunasin-Enriched Soybean Extract Potentially Useful in the Treatment of Helicobacter pylori Infection

Helicobacter pylori infection affects over 50% of the world's population and leads to chronic inflammation and gastric disorders, being the main pathogen correlated to gastric cancer development. Increasing antibiotic resistance levels are a major global concern and alternative treatments are needed. Soybean peptides and other compounds might be an alternative in the treatment to avoid, eradicate and/or control symptoms of H. pylori infection. This study aimed to characterize a lunasin-enriched soybean extract (LSE) using proteomics tools and to evaluate its antioxidant, anti-inflammatory and antibacterial properties against H. pylori infection. By LC-MS/MS analysis, 124 proteins were identified, with 2S albumin (lunasin and large-chain subunits) being the fourth most abundant protein (8.9%). Lunasin consists of 44 amino acid residues and an intramolecular disulfide bond. LSE at a low dose (0.0625 mg/mL) reduced ROS production in both H. pylori-infected and non-infected AGS gastric cells. This led to a significant reduction of 6.71% in the levels of pro-inflammatory interleukin (IL)-8. LSE also showed antibacterial activity against H. pylori, which can be attributed to other soybean proteins and phenolic compounds. Our findings suggest that LSE might be a promising alternative in the management of H. pylori infection and its associated symptoms.

Novel therapeutic regimens against Helicobacter pylori: an updated systematic review

Helicobacter pylori (H. pylori) is a strict microaerophilic bacterial species that exists in the stomach, and H. pylori infection is one of the most common chronic bacterial infections affecting humans. Eradicating H. pylori is the preferred method for the long-term prevention of complications such as chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. However, first-line treatment with triple therapy and quadruple therapy has been unable to cope with increasing antibacterial resistance. To provide an updated review of H. pylori infections and antibacterial resistance, as well as related treatment options, we searched PubMed for articles published until March 2024. The key search terms were "H. pylori", "H. pylori infection", "H. pylori diseases", "H. pylori eradication", and "H. pylori antibacterial resistance." Despite the use of antimicrobial agents, the annual decline in the eradication rate of H. pylori continues. Emerging eradication therapies, such as the development of the new strong acid blocker vonoprazan, probiotic adjuvant therapy, and H. pylori vaccine therapy, are exciting. However, the effectiveness of these treatments needs to be further evaluated. It is worth mentioning that the idea of altering the oxygen environment in gastric juice for H. pylori to not be able to survive is a hot topic that should be considered in new eradication plans. Various strategies for eradicating H. pylori, including antibacterials, vaccines, probiotics, and biomaterials, are continuously evolving. A novel approach involving the alteration of the oxygen concentration within the growth environment of H. pylori has emerged as a promising eradication strategy.

Analysis of programmed frameshifting during translation of prfB in Flavobacterium johnsoniae

Ribosomes of Bacteroidia fail to recognize Shine-Dalgarno (SD) sequences due to sequestration of the 3' tail of the 16S rRNA on the 30S platform. Yet in these organisms, the prfB gene typically contains the programmed +1 frameshift site with its characteristic SD sequence. Here, we investigate prfB autoregulation in Flavobacterium johnsoniae, a member of the Bacteroidia. We find that the efficiency of prfB frameshifting in F. johnsoniae is low (∼7%) relative to that in Escherichia coli (∼50%). Mutation or truncation of bS21 in F. johnsoniae increases frameshifting substantially, suggesting that anti-SD (ASD) sequestration is responsible for the reduced efficiency. The frameshift site of certain Flavobacteriales, such as Winogradskyella psychrotolerans, has no SD. In F. johnsoniae, this W. psychrotolerans sequence supports frameshifting as well as the native sequence, and mutation of bS21 causes no enhancement. These data suggest that prfB frameshifting normally occurs without SD-ASD pairing, at least under optimal laboratory growth conditions. Chromosomal mutations that remove the frameshift or ablate the SD confer subtle growth defects in the presence of paraquat or streptomycin, respectively, indicating that both the autoregulatory mechanism and the SD element contribute to F. johnsoniae cell fitness. Analysis of prfB frameshift sites across 2686 representative bacteria shows loss of the SD sequence in many clades, with no obvious relationship to genome-wide SD usage. These data reveal unexpected variation in the mechanism of frameshifting and identify another group of organisms, the Verrucomicrobiales, that globally lack SD sequences.

Reactive oxygen species and gastric carcinogenesis: The complex interaction between Helicobacter pylori and host

Helicobacter pylori (H. pylori) is a highly successful human pathogen that colonizes stomach in around 50% of the global population. The colonization of bacterium induces an inflammatory response and a substantial rise in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), mostly derived from host neutrophils and gastric epithelial cells, which play a crucial role in combating bacterial infections. However, H. pylori has developed various strategies to quench the deleterious effects of ROS, including the production of antioxidant enzymes, antioxidant proteins as well as blocking the generation of oxidants. The host's inability to eliminate H. pylori infection results in persistent ROS production. Notably, excessive ROS can disrupt the intracellular signal transduction and biological processes of the host, incurring chronic inflammation and cellular damage, such as DNA damage, lipid peroxidation, and protein oxidation. Markedly, the sustained inflammatory response and oxidative stress during H. pylori infection are major risk factor for gastric carcinogenesis. In this context, we summarize the literature on H. pylori infection-induced ROS production, the strategies used by H. pylori to counteract the host response, and subsequent host damage and gastric carcinogenesis.

Unrecognized risk of perfluorooctane sulfonate in promoting conjugative transfers of bacterial antibiotic resistance genes

Antibiotic resistance is a major global health crisis facing humanity, with horizontal gene transfer (HGT) as a principal dissemination mechanism in the natural and clinical environments. Perfluoroalkyl substances (PFASs) are emerging contaminants of global concern due to their high persistence in the environment and adverse effects on humans. However, it is unknown whether PFASs affect the HGT of bacterial antibiotic resistance. Using a genetically engineered Escherichia coli MG1655 as the donor of plasmid-encoded antibiotic resistance genes (ARGs), E. coli J53 and soil bacterial community as two different recipients, this study demonstrated that the conjugation frequency of ARGs between two E. coli strains was (1.45 ± 0.17) × 10-5 and perfluorooctane sulfonate (PFOS) at environmentally relevant concentrations (2-50 μg L-1) increased conjugation transfer between E. coli strains by up to 3.25-fold. Increases in reactive oxygen species production, cell membrane permeability, biofilm formation capacity, and cell contact in two E. coli strains were proposed as major promotion mechanisms from PFOS exposure. Weighted gene co-expression network analysis of transcriptome data identified a series of candidate genes whose expression changes could contribute to the increase in conjugation transfer induced by PFOS. Furthermore, PFOS also generally increased the ARG transfer into the studied soil bacterial community, although the uptake ability of different community members of the plasmid either increased or decreased upon PFOS exposure depending on specific bacterial taxa. Overall, this study reveals an unrecognized risk of PFOS in accelerating the dissemination of antibiotic resistance. IMPORTANCE Perfluoroalkyl substances (PFASs) are emerging contaminants of global concern due to their high persistence in the environment and adverse health effects. Although the influence of environmental pollutants on the spread of antibiotic resistance, one of the biggest threats to global health, has attracted increasing attention in recent years, it is unknown whether environmental residues of PFASs affect the dissemination of bacterial antibiotic resistance. Considering PFASs, often called "forever" compounds, have significantly higher environmental persistence than most emerging organic contaminants, exploring the effect of PFASs on the spread of antibiotic resistance is more environmentally relevant and has essential ecological and health significance. By systematically examining the influence of perfluorooctane sulfonate on the antibiotic resistance gene conjugative transfer, not only at the single-strain level but also at the community level, this study has uncovered an unrecognized risk of PFASs in promoting conjugative transfers of bacterial antibiotic resistance genes, which could be incorporated into the risk assessment framework of PFASs.

Reactive Oxygen Species and H. pylori Infection: A Comprehensive Review of Their Roles in Gastric Cancer Development

Gastric cancer (GC) is the fifth most common cancer worldwide and makes up a significant component of the global cancer burden. Helicobacter pylori (H. pylori) is the most influential risk factor for GC, with the International Agency for Research on Cancer classifying it as a Class I carcinogen for GC. H. pylori has been shown to persist in stomach acid for decades, causing damage to the stomach's mucosal lining, altering gastric hormone release patterns, and potentially altering gastric function. Epidemiological studies have shown that eliminating H. pylori reduces metachronous cancer. Evidence shows that various molecular alterations are present in gastric cancer and precancerous lesions associated with an H. pylori infection. However, although H. pylori can cause oxidative stress-induced gastric cancer, with antioxidants potentially being a treatment for GC, the exact mechanism underlying GC etiology is not fully understood. This review provides an overview of recent research exploring the pathophysiology of H. pylori-induced oxidative stress that can cause cancer and the antioxidant supplements that can reduce or even eliminate GC occurrence.

Helicobacter pylori in the post-antibiotics era: from virulence factors to new drug targets and therapeutic agents

Helicobacter pylori is considered one of the most prevalent human pathogenic microbes globally. It is the main cause of a number of gastrointestinal ailments, including peptic and duodenal ulcers, and gastric tumors with high mortality rates. Thus, eradication of H. pylori is necessary to prevent gastric cancer. Still, the rise in antibiotic resistance is the most important challenge for eradication strategies. Better consideration of H. pylori virulence factors, pathogenesis, and resistance is required for better eradication rates and, thus, prevention of gastrointestinal malignancy. This article is aimed to show the role of virulence factors of H. pylori. Some are involved in its survival in the harsh environment of the human gastric lumen, and others are related to pathogenesis and the infection process. Furthermore, this work has highlighted the recent advancement in H. pylori treatment, as well as antibiotic resistance as a main challenge in H. pylori eradication. Also, we tried to provide an updated summary of the evolving H. pylori control strategies and the potential alternative drugs to fight this lethal resistant pathogen. Recent studies have focused on evaluating the efficacy of alternative regimens (such as sequential, hybrid, concomitant treatment, vonoprazan (VPZ)-based triple therapy, high-dose PPI-amoxicillin dual therapy, probiotics augmented triple therapy, or in combination with BQT) in the effective eradication of H. pylori. Thus, innovating new anti-H. pylori drugs and establishing H. pylori databanks are upcoming necessities in the near future.

Biofilm of Helicobacter pylori: Life Cycle, Features, and Treatment Options

Helicobacter pylori is a gastric pathogen that infects nearly half of the global population and is recognized as a group 1 carcinogen by the Word Health Organization. The global rise in antibiotic resistance has increased clinical challenges in treating H. pylori infections. Biofilm growth has been proposed to contribute to H. pylori's chronic colonization of the host stomach, treatment failures, and the eventual development of gastric diseases. Several components of H. pylori have been identified to promote biofilm growth, and several of these may also facilitate antibiotic tolerance, including the extracellular matrix, outer membrane proteins, shifted morphology, modulated metabolism, efflux pumps, and virulence factors. Recent developments in therapeutic approaches targeting H. pylori biofilm have shown that synthetic compounds, such as small molecule drugs and plant-derived compounds, are effective at eradicating H. pylori biofilms. These combined topics highlight the necessity for biofilm-based research in H. pylori, to improve current H. pylori-targeted therapeutic approaches and alleviate relative public health burden. In this review we discuss recent discoveries that have decoded the life cycle of H. pylori biofilms and current biofilm-targeted treatment strategies.

Discovery of Novel Resistance Mechanisms of Vibrio parahaemolyticus Biofilm against Aminoglycoside Antibiotics

Inappropriate use of antibiotics eventually leads to the emergence of antibiotic-resistant strains and invalidates the treatment of infectious diseases. Aminoglycoside antibiotics (AGAs) are a class of broad-spectrum cationic antibiotics widely used for the treatment of Gram-negative bacterial infections. Understanding the AGA resistance mechanism of bacteria would increase the efficacy of treating these infections. This study demonstrates a significant correlation between AGA resistance and the adaptation of biofilms by Vibrio parahaemolyticus (VP). These adaptations were the result of challenges against the aminoglycosides (amikacin and gentamicin). Confocal laser scanning microscope (CLSM) analysis revealed an enclosure type mechanism where the biological volume (BV) and average thickness (AT) of V. parahaemolyticus biofilm were significantly positively correlated with amikacin resistance (BIC) (p < 0.01). A neutralization type mechanism was mediated by anionic extracellular polymeric substances (EPSs). The biofilm minimum inhibitory concentrations of amikacin and gentamicin were reduced from 32 µg/mL to 16 µg/mL and from 16 µg/mL to 4 µg/mL, respectively, after anionic EPS treatment with DNase I and proteinase K. Here, anionic EPSs bind cationic AGAs to develop antibiotic resistance. Transcriptomic sequencing revealed a regulatory type mechanism, where antibiotic resistance associated genes were significantly upregulated in biofilm producing V. parahaemolyticus when compared with planktonic cells. The three mechanistic strategies of developing resistance demonstrate that selective and judicious use of new antibiotics are needed to win the battle against infectious disease.

Helicobacter pylori Dormant States Are Affected by Vitamin C

Helicobacter pylori colonizes human gastric mucosa, overcoming stressful conditions and entering in a dormant state. This study evaluated: (i) H. pylori's physiological changes from active to viable-but-non-culturable (VBNC) and persister (AP) states, establishing times/conditions; (ii) the ability of vitamin C to interfere with dormancy generation/resuscitation. A dormant state was induced in clinical MDR H. pylori 10A/13 by: nutrient starvation (for VBNC generation), incubating in an unenriched medium (Brucella broth) or saline solution (SS), and (for AP generation) treatment with 10xMIC amoxicillin (AMX). The samples were monitored after 24, 48, and 72 h, 8-14 days by OD₆₀₀, CFUs/mL, Live/Dead staining, and an MTT viability test. Afterwards, vitamin C was added to the H. pylori suspension before/after the generation of dormant states, and monitoring took place at 24, 48, and 72 h. The VBNC state was generated after 8 days in SS, and the AP state in AMX for 48 h. Vitamin C reduced its entry into a VBNC state. In AP cells, Vitamin C delayed entry, decreasing viable coccal cells and increasing bacillary/U-shaped bacteria. Vitamin C increased resuscitation (60%) in the VBNC state and reduced the aggregates of the AP state. Vitamin C reduced the incidence of dormant states, promoting the resuscitation rate. Pretreatment with Vitamin C could favor the selection of microbial vegetative forms that are more susceptible to H. pylori therapeutical schemes.

Identification of anti-Helicobacter pylori antibody signatures in gastric intestinal metaplasia

BACKGROUND

Chronic Helicobacter pylori infection may induce gastric intestinal metaplasia (IM). We compared anti-H. pylori antibody profiles between IM cases and non-atrophic gastritis (NAG) controls.

METHODS

We evaluated humoral responses to 1528 H. pylori proteins among a discovery set of 50 IM and 50 NAG using H. pylori protein arrays. Antibodies with ≥ 20% sensitivity at 90% specificity for either group were selected and further validated in an independent set of 100 IM and 100 NAG using odds ratios (OR). A validated multi-signature was evaluated using the area under the receiver operating characteristics curve (AUC) and net reclassification improvement (NRI).

RESULTS

Sixty-two immunoglobulin (Ig) G and 11 IgA antibodies were detected in > 10%. Among them, 22 IgG and 6 IgA antibodies were different between IM and NAG in the discovery set. Validated antibodies included 11 IgG (anti-HP1177/Omp27/HopQ [OR = 8.1, p < 0.001], anti-HP0547/CagA [4.6, p < 0.001], anti-HP0596/Tipα [4.0, p = 0.002], anti-HP0103/TlpB [3.8, p = 0.001], anti-HP1125/PalA/Omp18 [3.1, p = 0.001], anti-HP0153/RecA [0.48, p = 0.03], anti-HP0385 [0.41, p = 0.006], anti-HP0243/TlpB [0.39, p = 0.016], anti-HP0371/FabE [0.37, p = 0.017], anti-HP0900/HypB/AccB [0.35, p = 0.048], and anti-HP0709 [0.30, p = 0.003]), and 2 IgA (anti-HP1125/PalA/Omp18 [2.7, p = 0.03] and anti-HP0596/Tipα [2.5, p = 0.027]). A model including all 11 IgG antibodies (AUC = 0.81) had better discriminated IM and NAG compared with an anti-CagA only (AUC = 0.77) model (NRI = 0.44; p = 0.001).

CONCLUSIONS

Our study represents the most comprehensive assessment of anti-H. pylori antibody profiles in IM. The target antigens for these novel antibodies may act together with CagA in the progression to IM. Along with other biomarkers, specific H. pylori antibodies may identify IM patients, who would benefit from surveillance.

The Role of Helicobacter pylori Neutrophil-Activating Protein in the Pathogenesis of H. pylori and Beyond: From a Virulence Factor to Therapeutic Targets and Therapeutic Agents

Helicobacter pylori neutrophil-activating protein (HP-NAP), a major virulence factor of H. pylori, plays a role in bacterial protection and host inflammation. HP-NAP activates a variety of innate immune cells, including neutrophils, monocytes, and mast cells, to induce their pro-oxidant and pro-inflammatory activities. This protein also induces T-helper type 1 (Th1) immune response and cytotoxic T lymphocyte (CTL) activity, supporting that HP-NAP is able to promote gastric inflammation by activation of adaptive immune responses. Thus, HP-NAP is a potential therapeutic target for the treatment of H. pylori-induced gastric inflammation. The inflammatory responses triggered by HP-NAP are mediated by a PTX-sensitive G protein-coupled receptor and Toll-like receptor 2. Drugs designed to block the interactions between HP-NAP and its receptors could alleviate the inflammation in gastric mucosa caused by H. pylori infection. In addition, HP-NAP acts as a promising therapeutic agent for vaccine development, allergy treatment, and cancer immunotherapy. The high antigenicity of HP-NAP makes this protein a component of vaccines against H. pylori infection. Due to its immunomodulatory activity to stimulate the Th1-inducing ability of dendritic cells, enhance Th1 immune response and CTL activity, and suppress Th2-mediated allergic responses, HP-NAP could also act as an adjuvant in vaccines, a drug candidate against allergic diseases, and an immunotherapeutic agent for cancer. This review highlights the role of HP-NAP in the pathogenesis of H. pylori and the potential for this protein to be a therapeutic target in the treatment of H. pylori infection and therapeutic agents against H. pylori-associated diseases, allergies, and cancer.

Trends in Helicobacter pylori-related gastric ulcer research from 2012 to 2022: A bibliometric and visual analysis

Background

Helicobacter pylori-related gastric ulcer (H. pylori-related GU) is one of the most common digestive system diseases that have received widespread attention from researchers. The purpose of this article was to analyze the research status and hotspots of H. pylori-related GU and to predict its future research directions.

Methods

The article and review papers associated with H. pylori-related GU published from 2012 to 2022 were retrieved from the Web of Science Core Collection (WoSCC). The analysis of knowledge maps and bibliometrics was done with CiteSpace 6.1.R2 Basic and VOSviewer 1.6.18.

Results

A total of 2,971 articles were included in the study. Between 2012 and 2022, the number of papers published showed an increasing trend. China was the most prolific country, and the United States was the most influential country. Baylor College of Medicine had the largest number of publications and citations among publishing agencies. World Journal of Gastroenterology published the most articles on the H. pylori-related GU field, and GUT was the journal with the most cited articles. Yamaoka Y from Japan was the most productive author, and Graham DY from the USA was the most influential author. A keyword and reference analysis showed that the hot topics of research were the mechanism of H. pylori and the treatment of H. pylori-related GU. The keywords that emerged in the recent 5 years were oxidative stress, probiotics, competitive acid blocker, vonoprazan, gut microbiota, and neutrophil-activating protein.

Conclusion

Over the recent 10 years, research on H. pylori-related GU has generally shown an increasing trend. The treatment and pathogenesis of H. pylori-related GU remain a hot topic of research. The treatment of H. pylori by oxidative stress and competitive acid inhibitor mechanisms, the influence of gastrointestinal flora on H. pylori, probiotic adjuvant therapy of H. pylori-related GU, and the immunoprotective effect of neutrophil activator protein could be popular research directions and trends in the future.

Revealing the novel effect of Jinghua Weikang capsule against the antibiotic resistance of Helicobacter pylori

Background

Helicobacter pylori (H. pylori) infects half of the human population globally. Eradication rates with triple or quadruple therapy have decreased owing to the increasing rate of antibiotic resistance. Jinghua Weikang capsule (JWC) is the first and most popular Chinese patent medicine approved by the state for the treatment of gastritis and peptic ulcers caused by H. pylori infection in China. Previous studies have found that JWC has a certain bactericidal effect on drug-resistant H. pylori and its major component, Chenopodium ambrosioides L. inhibits biofilm formation, but the mechanism remains unclear. This study focused on drug-resistant H. pylori and explored whether JWC could reverse drug resistance and its related mechanisms.

Method

The agar plate dilution method, E-test method, and killing kinetics assay were used to evaluate the bactericidal effect of JWC on antibiotic-resistant H. pylori and its effect on antibiotic resistance. Sanger sequencing was used to detect mutations in drug resistance genes. The crystal violet method, scanning electron microscopy, and confocal laser scanning microscopy were used to evaluate the effects of JWC on biofilms. qPCR was performed to evaluate the effect of JWC on the expression of efflux pump-related genes. qPCR and immunofluorescence were used to evaluate the effects of JWC on H. pylori adhesion.

Results

JWC showed considerable antibacterial activity against drug-resistant H. pylori strains, with minimum inhibitory concentration (MIC) values ranging from 64 to 1,024 μg/ml. The MIC of metronidazole (MTZ) against H. pylori 26,695–16R decreased from 64 to 6 μg/ml after treatment with 1/2 MIC of JWC. The resistance of H. pylori 26,695–16R to MTZ was reversed by JWC, and its effect was better than that of PaβN and CCCP. H. pylori 26,695–16R is a moderate biofilm-forming strain, and JWC (16–64 μg/ml) can inhibit the formation of biofilms in H. pylori 26,695–16R. JWC reduced the expression of HP0605-HP0607 (hefABC), HP0971-HP0969 (hefDEF), HP1327-HP1329 (hefGHI), and HP1489-HP1487. JWC reduced the adhesion of H. pylori to GES-1 cells and the expression of adhesives NapA, SabA, and BabA.

Conclusion

The reversal of MTZ resistance by JWC may be achieved through the adhesin/efflux pump-biofilm pathway.

Dynamics of Oxidative Stress in Helicobacter pylori-Positive Patients with Atrophic Body Gastritis and Various Stages of Gastric Cancer

Gastric cancer is a global health problem. The pathogenesis of this disease remains unclear. This study included 198 H. pylori (+) men aged 45 to 60 years old. Group A included 63 practically healthy men, group B included 45 men with severe atrophic body gastritis, group C included 37 men with epithelial gastric cancer stages I-II according to TNM, and group D included 54 men with epithelial gastric cancer stages III-IV according to the TNM scale. The content of malondialdehyde (MDA), diene conjugates (DCs), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPO) was detected using an enzyme immunoassay (ELISA) or spectrophotometric methods in the blood plasma. The concentrations of MDA and DC were increased in the patients of group B compared with group A, and in patients of groups C and D compared with groups A and B. The ratio of MDA/SOD and MDA/CAT was decreased in the patients in group D compared with the patients in group C, and was significantly higher compared with group A. The ratios of MDA/GPO and MDA/GST increased linearly and were at a maximum in groups C and D. Our work determined that indicators of oxidative stress may be the biochemical substrate, which brings together the various stages of the Correa cascade, and may explain disease progression. The dynamics of changes in the content of SOD and CAT in the plasma in patients with gastric cancer may be a target of future investigations.

Helicobacter pylori Biofilm-Related Drug Resistance and New Developments in Its Anti-Biofilm Agents

Helicobacter pylori is one of the most common pathogenic bacterium worldwide, infecting about 50% of the world's population. It is a major cause of several upper gastrointestinal diseases, including peptic ulcers and gastric cancer. The emergence of H. pylori resistance to antibiotics has been a major clinical challenge in the field of gastroenterology. In the course of H. pylori infection, some bacteria invade the gastric epithelium and are encapsulated into a self-produced matrix to form biofilms that protect the bacteria from external threats. Bacteria with biofilm structures can be up to 1000 times more resistant to antibiotics than planktonic bacteria. This implies that targeting biofilms might be an effective strategy to alleviate H. pylori drug resistance. Therefore, it is important to develop drugs that can eliminate or disperse biofilms. In recent years, anti-biofilm agents have been investigated as alternative or complementary therapies to antibiotics to reduce the rate of drug resistance. This article discusses the formation of H. pylori biofilms, the relationship between biofilms and drug resistance in H. pylori, and the recent developments in the research of anti-biofilm agents targeting H. pylori drug resistance.

Transcriptome Analysis of the Response of Mature Helicobacter pylori Biofilm to Different Doses of Lactobacillus salivarius LN12 with Amoxicillin and Clarithromycin

Helicobacter pylori is a gastrointestinal pathogen with a high infection rate. Probiotics are clinically used as an adjuvant to improve the cure rate and reduce the side effects of antibiotic treatment for H. pylori. This study is the first to explore the effects of a cell-free supernatant of high- or low-dose Lactobacillus salivarius LN12 combined with amoxicillin (AMX) and clarithromycin (CLR) on H. pylori 3192 biofilms in terms of the biofilm biomass, survival rates, biofilm structure, and transcriptome. The results showed that the combination of the CFS of high-dose LN12 with AMX and CLR had stronger effects on the biofilm biomass, survival rate, and structure of H. pylori 3192 biofilms. H. pylori 3192 biofilms may increase the expression of NADH-related genes and downregulate flagellar assembly and quorum sensing-related receptor genes to deal with the stronger stress effects of high-dose LN12 with AMX and CLR. In conclusion, the biofilm biomass, survival rate, structure, and transcriptome results showed that the combination of LN12 CFS with AMX and CLR had dose effects. We recommend that compared with low doses, high doses of L. salivarus LN12 combined with AMX and CLR may be more effective for H. pylori biofilm than low doses.

The Diguanylate Cyclase YfiN of Pseudomonas aeruginosa Regulates Biofilm Maintenance in Response to Peroxide

Pseudomonas aeruginosa forms surface-attached communities that persist in the face of antimicrobial agents and environmental perturbation. Published work has found extracellular polysaccharide (EPS) production, regulation of motility and induction of stress response pathways as contributing to biofilm tolerance during such insults. However, little is known regarding the mechanism(s) whereby biofilm maintenance is regulated when exposed to such environmental challenges. Here, we provide evidence that the diguanylate cyclase YfiN is important for the regulation of biofilm maintenance when exposed to peroxide. We find that, compared to the wild type (WT), static biofilms of the ΔyfiN mutant exhibit a maintenance defect, which can be further exacerbated by exposure to peroxide (H₂O₂); this defect can be rescued through genetic complementation. Additionally, we found that the ΔyfiN mutant biofilms produce less c-di-GMP than WT, and that H₂O₂ treatment enhanced motility of surface-associated bacteria and increased cell death for the ΔyfiN mutant grown as a biofilm compared to WT biofilms. These data provide evidence that YfiN is required for biofilm maintenance by P. aeruginosa, via c-di-GMP signaling, to limit motility and protect viability in response to peroxide stress. These findings add to the growing recognition that biofilm maintenance by P. aeruginosa is an actively regulated process that is controlled, at least in part, by the wide array of c-di-GMP metabolizing enzymes found in this microbe. Importance We build on previous findings that suggest that P. aeruginosa utilizes c-di-GMP metabolizing enzymes to actively maintain a mature biofilm. Here, we explore how the diguanylate cyclase YfiN contributes to the regulation of biofilm maintenance during peroxide exposure. We find that mature P. aeruginosa biofilms require YfiN to synthesize c-di-GMP, regulate motility and to insure viability during peroxide stress. These findings provide further evidence that the modulation of c-di-GMP in response to environmental signals is an important mechanism by which biofilms are maintained.