The relation of Helicobacter pylori to gastric adenocarcinoma and lymphoma: pathophysiology, epidemiology, screening, clinical presentation, treatment, and prevention

The Role of the Gut Microbiome in Cancer: A Review, With Special Focus on Colorectal Neoplasia and Clostridioides difficile

The gut microbiome has coevolved with humans to aid in physiologic functions and prevent disease. An increasing prevalence of gut dysbiosis in modern society exists and has strong linkages to multiple disease processes common in the developed world. Mechanisms for microbiome-human interactions that impact host homeostasis include bacterial metabolite/toxin production, biofilm formation with mucous layer infiltration, and host immune system modulation. Most of this crosstalk occurs at the epithelial layer of the gut, and as such the role of these interactions in the induction of colorectal cancer-a highly prevalent disease globally and one undergoing significant epidemiologic shifts-is under increasing scrutiny. Although multiple individual gut bacteria have been hypothesized as possible driver organisms in the oncogenic process, no bacterium has been definitively identified as a causal agent of colorectal cancer, suggesting that host lifestyle factors, microbiome community interactions, and the mucosal and/or systemic immune response may play a critical role in the process. Recent evidence has emerged implicating the ubiquitous human pathogen Clostridioides difficile as a possible promoter of colorectal cancer through chronic toxin-mediated cellular changes. Although much remains to be defined regarding the natural history of infections caused by this pathogen and its potential for oncogenesis, it provides a strong model for the role of both individual bacteria and of the gut microbial community as a whole in the development of colorectal cancer.

Real-time in vivo ROS monitoring with luminescent nanoparticles reveals skin inflammation dynamics

Reactive oxygen species (ROS) are key regulators in numerous pathological contexts, including cancer or inflammation. Their role is complex, which justifies the need for methods enabling their quantitative and time-resolved monitoring in vivo, in the perspective to profile tissues of individual patients. However, current ROS detection methods do not provide these features. Here, we propose a new method based on the imaging of lanthanide-ion nanoparticles (GdVO4:Eu), whose photoluminescence is modulated by the surrounding ROS concentration. We monitored their luminescence after intradermic injection in a mouse ear submitted to an inflammation-inducing topical stimulus. Based on this approach, we quantified the ROS concentration after inflammation induction and identified a two-step kinetics of ROS production, which may be attributed to the response of resident immune cells and their further recruitment at the inflammation locus.

The Association of Helicobacter pylori Biofilm with Enterovirus 71 Prolongs Viral Viability and Survival

The transition time during which a virus leaves its host and infects the next susceptible host is critical for virus survival. Enterovirus 71 (EV71) is stable in aqueous environments, but its molecular interactions with bacteria and their biofilms are not well-established. Helicobacter pylori is a highly successful gut bacterial pathogen, with its capacity to form biofilms being linked to its transmission. Given that both are gut-associated microbes, we hypothesized that biofilms formed by H. pylori may play a significant role in the survival of EV71 in the external environment. In this study, we examine the interactions of EV71 with the preformed biofilm of H. pylori to mimic its natural state in the environment. Immunofluorescence confocal microscopy and scanning electron microscopy revealed that EV71 particles persisted for up to 10 days when incubated with the H. pylori biofilm. Furthermore, the presence of the H. pylori biofilm significantly augmented viral viability, as verified through virus plaque assays. Interestingly, the viability of EV71 was dependent on the quantity of H. pylori biofilm formation. Thus, two H. pylori strains able to generate large amounts of biofilm could facilitate EV71 viability for up to 17 days, whereas two other H. pylori strains that produced moderate or low quantities of biofilm could not prolong virus viability. It is interesting that biofilm contains N-acetyl-glucosamine and glycosaminoglycan, and that EV71 has binding affinity to cell-surface heparan sulfate glycosaminoglycan, which acts as an EV71 attachment receptor. The synergistic ability of H. pylori biofilm to promote EV71 viability for extended periods implies that H. pylori biofilm may serve as an additional pathway of EV71 transmission.

Lactiplantibacillus plantarum ZJ316 Reduces Helicobacter pylori Adhesion and Inflammation by Inhibiting the Expression of Adhesin and Urease Genes

SCOPE

The present study aims to investigate the anti-Helicobacter pylori (H. pylori) effects of Lactiplantibacillus plantarum ZJ316 (L. plantarum ZJ316) both in vitro and in vivo.

METHODS AND RESULTS

This study finds that L. plantarum ZJ316 effectively suppresses H. pylori adhesion in inhibition (Pre-ZJ316), competition (Co-ZJ316), and displacement (Post-ZJ316) assays, and Pre-ZJ316 displaying the most potent inhibitory effect with an impressive inhibition ratio of 70.14%. Upon anti-adhesion, L. plantarum ZJ316 significantly downregulates the expression of H. pylori virulence genes, including ureA, ureB, flaA, and sabA, with inhibition ratios of 46.83%, 24.02%, 21.42%, and 62.38% at 2 h, respectively. In addition, L. plantarum ZJ316 is observed to reduce the level of interleukin 8 (IL-8) and improve cell viability in infected AGS cells. Furthermore, in vivo studies show that supplementation with L. plantarum ZJ316 effectively hinders H. pylori colonization and significantly suppresses the infiltration of immune cells and IL-8 production with H. pylori infection, protecting host from inflammatory damage.

CONCLUSION

L. plantarum ZJ316 exhibits excellent adhesion inhibition on H. pylori, and may be used as a probiotic candidate in the prevention or adjuvant therapy of gastric disease caused by H. pylori.

Ellagitannins from Castanea sativa Mill. Leaf Extracts Impair H. pylori Viability and Infection-Induced Inflammation in Human Gastric Epithelial Cells

Helicobacter pylori (H. pylori) is an etiologic factor of peptic ulcer disease and gastric cancer. Virulent strains of H. pylori are correlated with the severity of gastritis, due to NF-κB activation and IL-8 expression at the epithelial level. Ellagitannins have been documented for antibacterial and anti-inflammatory activities, thus suggesting their potential use in gastritis. Recently, several authors, including our group, demonstrated that tannin-rich extracts from chestnut byproducts, at present considered agricultural waste, display promising biological activities. In this work, we detected high levels of polyphenols in hydroalcoholic extracts from chestnut leaves (Castanea sativa L.). Among polyphenols, the ellagitannin isomers castalagin and vescalagin (about 1% w/w of dry extract) were identified as potential bioactive compounds. In GES-1 cells infected by H. pylori, leaf extract and pure ellagitannins inhibited IL-8 release (IC₅₀ ≈ 28 µg/mL and 11 µM, respectively). Mechanistically, the anti-inflammatory activity was partly due to attenuation of NF-κB signaling. Moreover, the extract and pure ellagitannins reduced bacterial growth and cell adhesion. A simulation of the gastric digestion suggested that the bioactivity might be maintained after oral administration. At the transcriptional level, castalagin downregulated genes involved in inflammatory pathways (NF-κB and AP-1) and cell migration (Rho GTPase). To the best of our knowledge, this is the first investigation in which ellagitannins from plant extracts have demonstrated a potential role in the interaction among H. pylori and human gastric epithelium.

Effects of CYP2C19 genetic polymorphisms on the cure rates of H. pylori in patients treated with the proton pump inhibitors: An updated meta-analysis

Background: The cure rates of Helicobacter pylori (H. pylori) treatment using a proton pump inhibitor (PPI) are gradually decreasing due to antibiotic resistance, poor compliance, high gastric acidity, and cytochrome P450 2C19 (CYP2C19) polymorphism, and the effects of PPI depend on metabolic enzymes, cytochrome P450 enzymes. The aim of this meta-analysis was to determine whether CYP2C19 polymorphisms affect H. pylori cure rates in patients treated with different proton pump inhibitors (PPIs) according to stratified analysis.

Materials and methods: The literature was searched with the key words “H. pylori” and “CYP2C19” in PubMed, CNKI, and Wanfang up to 31 May 2022, and the studies were limited to clinical observational or randomized controlled trials (RCTs). Finally, seven RCTs and 29 clinical observational studies met the inclusion criteria and were used for the meta-analysis via STATA version 16.

Results: The cure rates were significantly different between genotypes of homozygous extensive metabolizers (EM) and poor metabolizers (PM) (OR = 0.58, 95% CI: 0.47–0.71) and between EM and heterozygous extensive metabolizers (IM) (OR = 0.71, 95% CI: 0.59–0.86), but not between IM and PM. Moreover, there was a significantly lower H. pylori cure rate in EM subjects than that in IM subjects when treated with omeprazole (66.4% vs. 84.1%), lansoprazole (76.1% vs. 85.6%), but not rabeprazole, esomeprazole, or pantoprazole. In addition, there was a significantly lower H. pylori cure rate in EM subjects than that in IM subjects when treated with a PPIs for 7 days (77.4% vs. 82.1%), but not 14 days (85.4% vs. 90.0%).

Conclusion: Carriers of CYP2C19 loss-of-function variant alleles (IM and PM) exhibit a significantly greater cure rate of H. pylori than noncarriers (EM) regardless of other factors (84.7% vs. 79.2%). In addition, pantoprazole- and rabeprazole-based quadruple therapy for H. pylori treatment is less dependent on the CYP2C19 genotype and should be prioritized in Asian populations with H. pylori.

Salivary Microbiome in Adenoid Cystic Carcinoma Detected by 16S rRNA Sequencing and Shotgun Metagenomics

Microorganisms are confirmed to be closely related to the occurrence and development of cancers in human beings. However, there has been no published report detailing relationships between the oral microbiota and salivary adenoid cystic carcinoma (SACC). In this study, unstimulated saliva was collected from 13 SACC patients and 10 healthy controls. The microbial diversities, compositions and functions were comprehensively analyzed after 16S rRNA sequencing and whole-genome shotgun metagenomic sequencing. The alpha diversity showed no significant difference between SACC patients and healthy controls, while beta diversity showed a separation trend. The SACC patients showed higher abundances of Streptococcus and Rothia, while Prevotella and Alloprevotella were more abundant in healthy controls. The prevalent KEGG pathways, carbohydrate-active enzymes, antibiotic resistances and virulence factors as well as the biomarkers in SACC were determined by functional gene analysis. Our study preliminarily investigated the salivary microbiome of SACC patients compared with healthy controls and might be the basis for further studies on novel diagnostic and treatment strategies.

Fusobacterium nucleatum predicts a high risk of metastasis for esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer in China. The role of the bacteria present in ESCC tissue in neoplastic progression has not been fully elucidated. This study aimed to uncover different bacterial communities in ESCC tissues and examine the correlation between the abundance of the esophageal flora and clinicopathologic characteristics of ESCC.

Results

Microorganisms in tumors and normal tissues showed obvious clustering characteristics. The abundance of Fusobacterium (P = 0.0052) was increased in tumor tissues. The high level of Fusobacterium nucleatum was significantly associated with pT stage (P = 0.039) and clinical stage (P = 0.0039). The WES data showed that COL22A1, TRBV10–1, CSMD3, SCN7A and PSG11 were present in only the F. nucleatum-positive ESCC samples. GO and protein domain enrichment results suggested that epidermal growth factor might be involved in the regulation of cell apoptosis in F. nucleatum-positive ESCC. Both a higher mutational burden and F. nucleatum-positive was observed in tumors with metastasis than in tumors without metastasis.

Conclusion

F. nucleatum is closely related to the pT stage and clinical stage of ESCC. The abundance of F. nucleatum and tumor mutation burden may be used in combination as a potential method to predict metastasis in ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02352-6.

Designing and development of epitope-based vaccines against Helicobacter pylori

Helicobacter pylori infection is the principal cause of serious diseases (e.g. gastric cancer and peptic ulcers). Antibiotic therapy is an inadequate strategy in H. pylori eradication because of which vaccination is an inevitable approach. Despite the presence of countless vaccine candidates, current vaccines in clinical trials have performed with poor efficacy which makes vaccination extremely challenging. Remarkable advancements in immunology and pathogenic biology have provided an appropriate opportunity to develop various epitope-based vaccines. The fusion of proper antigens involved in different aspects of H. pylori colonization and pathogenesis as well as peptide linkers and built-in adjuvants results in producing epitope-based vaccines with excellent therapeutic efficacy and negligible adverse effects. Difficulties of the in vitro culture of H. pylori, high genetic variation, and unfavourable immune responses against feeble epitopes in the complete antigen are major drawbacks of current vaccine strategies that epitope-based vaccines may overcome. Besides decreasing the biohazard risk, designing precise formulations, saving time and cost, and induction of maximum immunity with minimum adverse effects are the advantages of epitope-based vaccines. The present article is a comprehensive review of strategies for designing and developing epitope-based vaccines to provide insights into the innovative vaccination against H. pylori.

Recent chemical syntheses of bacteria related oligosaccharides using modern expeditious approaches

Apart from some essential and crucial roles in life processes carbohydrates also are involved in a few detrimental courses of action related to human health, like infections by pathogenic microbes, cancer metastasis, transplanted tissue rejection, etc. Regarding management of pathogenesis by microbes, keeping in mind of multi drug-resistant bacteria and epidemic or endemic incidents, preventive measure by vaccination is the best pathway as also recommended by the WHO; by vaccination, eradication of bacterial diseases is also possible. Although some valid vaccines based on attenuated bacterial cells or isolated pure polysaccharide-antigens or the corresponding conjugates thereof are available in the market for prevention of several bacterial diseases, but these are not devoid of some disadvantages also. In order to develop improved conjugate T-cell dependent vaccines oligosaccharides related to bacterial antigens are synthesized and converted to the corresponding carrier protein conjugates. Marketed Cuban Quimi-Hib is such a vaccine being used since 2004 to resist Haemophilus influenza b infections. During nearly the past two decades research is going on worldwide for improved synthesis of bacteria related oligosaccharides or polysaccharides towards development of such semisynthetic or synthetic glycoconjugate vaccines. The present dissertation is an endeavour to encompass the recent syntheses of several pathogenic bacterial oligosaccharides or polysaccharides, made during the past ten-eleven years with special reference to modern expeditious syntheses.

The Relationship between Mycoplasmas and Cancer: Is It Fact or Fiction ? Narrative Review and Update on the Situation

More than one million new cancer cases occur worldwide every year. Although many clinical trials are applied and recent diagnostic tools are employed, curing cancer disease is still a great challenge for mankind. Heredity and epigenetics are the main risk factors often related to cancer. Although, the infectious etiological role in carcinogenesis was also theorized. By establishing chronic infection and inflammation in their hosts, several microorganisms were suggested to cause cell transformation. Of these suspicious microorganisms, mycoplasmas were well regarded because of their intimate parasitism with host cells, as well as their silent and insidious role during infections. This assumption has opened many questions about the real role played by mycoplasmas in oncogenesis. Herein, we presented a sum up of many studies among the hundreds which had addressed the Mycoplasma-cancer topic over the past 50 years. Research studies in this field have first started by approving the mycoplasmas malignancy potential. Indeed, using animal models and in vitro experiments in various cell lines from human and other mammalians, many mycoplasmas were proven to cause varied modifications leading to cell transformation. Moreover, many studies have looked upon the Mycoplasma-cancer subject from an epidemiological point of view. Diverse techniques were used to assess the mycoplasmas prevalence in patients with cancer from different countries. Not less than 10 Mycoplasma species were detected in the context of at least 15 cancer types affecting the brain, the breast, the lymphatic system, and different organs in the genitourinary, respiratory, gastrointestinal, and urinary tracts. Based on these revelations, one should concede that detection of mycoplasmas often linked to ‘‘wolf in sheep's clothing” is not a coincidence and might have a role in cancer. Thorough investigations are needed to better elucidate this role. This would have a substantial impact on the improvement of cancer diagnosis and its prevention.

A re-testing range is recommended for 13C- and 14C-urea breath tests for Helicobacter pylori infection in China

Background

The urea breath test (UBT) is widely used for diagnosing Helicobacter pylori infection. In the Shenzhen Kuichong People’s Hospital, some UBT findings were contradictory to the histology outcomes, therefore this study aimed to assess and compare the diagnostic performance of both ¹³C- and ¹⁴C-UBT assays.

Methods

We recruited 484 H. pylori-treatment naïve patients, among which 217 and 267 were tested by the ¹³C-UBT or ¹⁴C-UBT, respectively. The cutoff value for H. pylori positivity based on manufacturer’s instruction was 4% delta over baseline (DOB) for the ¹³C-UBT, and 100 disintegrations per minute (DPM) for the ¹⁴C-UBT. Gastric biopsies of the antrum and corpus were obtained during endoscopy for histopathology.

Results

In patients who were tested using the ¹³C-UBT kit, histopathology was positive in 136 out of 164 UBT-positive patients (82.9% concordance), and negative in 46 out of 53 UBT-negative cases (86.8% concordance). For the ¹⁴C-UBT-tested patients, histopathology was positive for H. pylori in 186 out of 220 UBT-positive patients (84.5% concordance), and negative in 41 out of 47 UBT-negative cases (87.2% concordance). While the ¹³C-UBT and ¹⁴C-UBT each had a high sensitivity level of 95.1% and 96.9%, respectively, their specificity was low, at 62.2% and 54.7%, respectively. By using new optimal cutoff values and including an indeterminate range (3–10.3% DOB for ¹³C-UBT and 87–237 DPM for ¹⁴C-UBT), the specificity values can be improved to 76.7% and 76.9% for the ¹³C- and ¹⁴C-UBT, respectively.

Conclusions

The establishment of an indeterminate range is recommended to allow for repeated testing to confirm H. pylori infection, and thereby avoiding unnecessary antibiotic treatment.

Trial registration: Chinese Clinical Trial Registry, ChiCTR2000041570. Registered 29 December 2020- Retrospectively registered, http://www.chictr.org.cn/edit.aspx?pid=66416&htm=4

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00435-3.

Molecular detection of urogenital mollicutes in patients with invasive malignant prostate tumor

BACKGROUND

The etiology of prostate cancer (PCa) is multiple and complex. Among the causes recently cited are chronic infections engendered by microorganisms that often go unnoticed. A typical illustration of such a case is infection due to mollicutes bacteria. Generally known by their lurking nature, urogenital mollicutes are the most incriminated in PCa. This study was thus carried out in an attempt to establish the presence of these mollicutes by PCR in biopsies of confirmed PCa patients and to evaluate their prevalence.

METHODS

A total of 105 Formalin-Fixed Paraffin-Embedded prostate tissues collected from 50 patients suffering from PCa and 55 with benign prostate hyperplasia were subjected to PCR amplification targeting species-specific genes of 5 urogenital mollicutes species, Mycoplasma genitalium, M. hominis, M. fermentans, Ureaplasma parvum, and U. urealyticum. PCR products were then sequenced to confirm species identification. Results significance was statistically assessed using Chi-square and Odds ratio tests.

RESULTS

PCR amplification showed no positive results for M. genitalium, M. hominis, and M. fermentans in all tested patients. Strikingly, Ureaplasma spp. were detected among 30% (15/50) of PCa patients. Nucleotide sequencing further confirmed the identified ureaplasma species, which were distributed as follows: 7 individuals with only U. parvum, 5 with only U. urealyticum, and 3 co-infection cases. Association of the two ureaplasma species with PCa cases proved statistically significant (P < 0.05), and found to represent a risk factor. Of note, Ureaplasma spp. were mostly identified in patients aged 60 and above with prostatic specific antigen (PSA) level > 4 ng/ml and an invasive malignant prostate tumor (Gleason score 8-10).

CONCLUSIONS

This study uncovered a significant association of Ureaplasma spp. with PCa arguing in favour of their potential involvement in this condition. Yet, this finding, though statistically supported, warrants a thorough investigation at a much larger scale.

Microbiome dysbiosis in lung cancer: from composition to therapy

The correlations between microbiota dysbiosis and cancer have gained extensive attention and been widely explored. As a leading cancer diagnosis worldwide, lung cancer poses a great threat to human health. The healthy human lungs are consistently exposed to external environment and harbor a specific pattern of microbiota, sharing many key pathological and physiological characteristics with the intestinal tract. Although previous findings uncovered the critical roles of microbiota in tumorigenesis and response to anticancer therapy, most of them were focused on the intestinal microbiota rather than lung microbiota. Notably, the considerable functions of microbiota in maintaining lung homeostasis should not be neglected as the microbiome dysbiosis may promote tumor development and progression through production of cytokines and toxins and multiple other pathways. Despite the fact that increasing studies have revealed the effect of microbiome on the induction of lung cancer and different disease status, the underlying mechanisms and potential therapeutic strategies remained unclear. Herein, we summarized the recent progresses about microbiome in lung cancer and further discussed the role of microbial communities in promoting lung cancer progression and the current status of therapeutic approaches targeting microbiome to alleviate and even cure lung cancer.

Prevalence and risk factors of Helicobacter pylori infection among children in Kuichong Subdistrict of Shenzhen City, China

Background

Helicobacter pylori infection is a significant burden to the public health in China as it can lead to various gastric diseases including peptic ulcers and gastric cancer. Since most infections occurred during childhood, it is therefore necessary to understand the prevalence and risk determinants of this bacterial infection in children. Herewith, we conducted a cross-sectional study in the Kuichong Subdistrict of Shenzhen City to assess the prevalence and risk factors of H. pylori infection among children.

Methods

From September 2018 to October 2018, 1,355 children aged 6–12 years from four primary schools in the Kuichong Subdistrict of Shenzhen City were recruited. These children were screened for H. pylori infection using the ¹³C-urea breath test. In addition, parents were requested to fill out a standardized questionnaire. The chi-square test and multivariable logistic regression analysis were used to identify risk factors for H. pylori.

Results

Among 1,355 children recruited in this study, 226 (16.7%; 95% CI [14.7–18.7]) were positive of H. pylori infection. Multivariable logistic regression analysis identified six factors significantly associated with H. pylori infection children including parent(s) with tertiary education level (OR: 0.64; 95% CI [0.46–0.89]), testing bottle feed temperature using the mouth (OR: 1.79; 95% CI [1.19–2.68]), sharing of cutlery between the feeding person and young children during meals (OR: 1.84; 95% CI [1.22–2.78]), eating fruit after peeling (OR: 2.56; 95% CI [1.4–4.71]), frequent dining out (OR: 3.13; 95% CI [1.46–6.68]) and snacking (OR: 1.43; 95% CI [1.01–2.01]).

Conclusions

Overall, better educated parent(s) played a protective role against the acquisition of H. pylori infection in children. Testing bottle feed temperature using the mouth, cutlery sharing between the feeding person and young children, and snacking posed a lower but significant risk for H. pylori infection. Only eating peeled fruits and frequent dining out were associated with greater infection risks.

Influence of N-acylhomoserine lactonase silver nanoparticles on the quorum sensing system of Helicobacter pylori: A potential strategy to combat biofilm formation

The treatment of Helicobacter pylori usually fails due to their ability to form biofilms and resistance to antibiotics. This might potentially lead to gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. In the present study, we elucidate the potential role of N-acylhomoserine lactonase stabilized silver nanoparticles (AiiA-AgNPs) in treating biofilms produced by H. pylori. AiiA-AgNPs inhibited quorum sensing (QS) by degradation of QS molecules, thereby reducing biofilm formation, urease production, and altering cell surface hydrophobicity of H. pylori. AiiA-AgNPs showed no cytotoxic effects on RAW 264.7 macrophages at the effective concentration (1-5 µM) of antibiofilm activity. In addition, AiiA-AgNP in high concentration (80-100 µM) exhibited cytotoxicity against HCT-15 carcinoma cells, depicting its therapeutic role in treating cancer.

Total synthesis of theHelicobacter pyloriserotype O2 O-antigen α-(1 → 2)- and α-(1 → 3)-linked oligoglucosides

Unique α-(1 → 2)- and α-(1 → 3)-linked oligoglucosides from theH. pyloriserotype O2 O-antigen were synthesized with exclusive α-selectivity using remote participation effects.

Effect of Drug Combination on Omeprazole Metabolism by Cytochrome P450 2C19 in Helicobacter pylori Eradication Therapy

Helicobacter pylori (H. pylori) infection is common and can result in gastric and duodenal ulcers, and in some cases, gastric lymphoma and cancer. Omeprazole (OMP)-in combination with clarithromycin (CLR), amoxicillin (AMX), tinidazole (TND), or metronidazole (MET)-is used in double or triple combination therapy for eradication of H. pylori. However, the roles of the drugs other than OMP are not clearly understood. Therefore, in the present study, we aimed to investigate any effects of these drugs on OMP metabolism by wild-type CYP2C19 using spectroscopy and enzyme kinetics. The dissociation constants (K_d) for CYP2C19 with OMP, CLR, AMX, TND, and MET were 8.6, 126, 156, 174, and 249 µM, respectively. The intrinsic clearance of OMP was determined to be 355 mL/min/µmol of CYP2C19. Metabolism of OMP was significantly inhibited by 69, 66, 28, and 40% in the presence of CLR, TND, AMX, and MET, respectively. Moreover, the combination of CLR and TND resulted in 76% inhibition of OMP metabolism, while the combination of AMX and MET resulted in 48% inhibition of OMP metabolism. Both combinations of drugs not only have antibacterial effects, but also enhance the effect of OMP by inhibiting its metabolism by CYP2C19. These results indicate that drug-drug interactions of co-administered drugs can cause complex effects, providing a basis for OMP dose adjustment when used in combination therapy for H. pylori eradication.

An NFκB Activity Calculator to Delineate Signaling Crosstalk: Type I and II Interferons Enhance NFκB via Distinct Mechanisms

Nuclear factor kappa B (NFκB) is a transcription factor that controls inflammation and cell survival. In clinical histology, elevated NFκB activity is a hallmark of poor prognosis in inflammatory disease and cancer, and may be the result of a combination of diverse micro-environmental constituents. While previous quantitative studies of NFκB focused on its signaling dynamics in single cells, we address here how multiple stimuli may combine to control tissue level NFκB activity. We present a novel, simplified model of NFκB (SiMoN) that functions as an NFκB activity calculator. We demonstrate its utility by exploring how type I and type II interferons modulate NFκB activity in macrophages. Whereas, type I IFNs potentiate NFκB activity by inhibiting translation of IκBα and by elevating viral RNA sensor (RIG-I) expression, type II IFN amplifies NFκB activity by increasing the degradation of free IκB through transcriptional induction of proteasomal cap components (PA28). Both cross-regulatory mechanisms amplify NFκB activation in response to weaker (viral) inducers, while responses to stronger (bacterial or cytokine) inducers remain largely unaffected. Our work demonstrates how the NFκB calculator can reveal distinct mechanisms of crosstalk on NFκB activity in interferon-containing microenvironments.

[Oral microbiological diversity in patients with salivary adenoid cystic carcinoma]

OBJECTIVE

The aim of this study was to identify the differences in microbial diversity and community in patients with salivary adenoid cystic carcinoma (SACC).

METHODS

Saliva was collected from 13 patients with SACC confirmed by histopathological diagnosis and 10 healthy control subjects. Total metagenomic DNA was extracted. The DNA amplicons of the V3-V4 hypervariable regions of the 16S rRNA gene were generated and subjected to high-throughput sequencing. Microbial diversity and community structure were analyzed with Mothur software.

RESULTS

A total of 16 genera of dominant bacteria in the SACC group were found, including Streptococcus (36.68%), Neisseria (8.55%), Prevotella_7 (7.53%), and Veillonella (6.37%), whereas 15 dominant bacteria in the control group were found, including Streptococcus (18.41%), Neisseria (18.20%), Prevotella_7 (8.89%), Porphyromonas (6.20%), Fusobacterium (5.86%) and Veillonella (5.82%). The statistically different phyla between the two groups were Firmicutes, Proteobacteria and Fusobacterium (P<0.05). The statistically different genera between the two groups were Streptococcus, Neisseria and Porphyromonas (P<0.05), and Capnocytophaga was only detected in patients with SACC.

CONCLUSIONS

Significant differences were observed in the oral microorganisms between the two groups.

Gastric Helicobacter pylori infection perturbs human oral microbiota

Background

We investigated the effects of gastric Helicobacter pylori infection on the daytime and overnight human oral microbiota.

Methods

Twenty four volunteers were recruited. Ten tested positive for H. pylori infection by the Carbon-14 Urea Breath Test, and the rest were negative. Two oral swabs were collected: one immediately after waking up in the morning and before brushing teeth, and another in the evening before teeth-brushing. DNA extract acquired from each swab was subjected to Illumina sequencing of 16S rRNA gene amplicons. The microbial abundance and composition were analysed in relation to H. pylori infection status.

Results

Helicobacter pylori-positive individuals had significant changes in the alpha and beta diversities in the daytime samples in comparison to those who were H. pylori negative. To identify which taxa could be significantly affected within the cohorts in the daytime, we employed the LEfSe method. When compared against UBT-negative samples, significantly higher abundances were detected in both Pseudomonas and Roseomonas, while Fusobacterium, Solobacterium, Haemophilus and Streptococcus were significantly decreased in the UBT-positive samples.

Discussion

Our data demonstrated that H. pylori infection affects the human daytime oral microbiota. The hitherto undocumented changes of several bacterial genera due to H. pylori infection require more studies to examine their potential health effects on affected individuals.

Analysis of core protein clusters identifies candidate variable sites conferring metronidazole resistance in Helicobacter pylori

Background

Metronidazole is one of the first-line drugs of choice in the standard triple therapy used to eradicate Helicobacter pylori infection. Hence, the global emergence of metronidazole resistance in Hp poses a major challenge to health professionals. Inactivation of RdxA is known to be a major mechanism of conferring metronidazole resistance in H. pylori. However, metronidazole resistance can also arise in H. pylori strains expressing functional RdxA protein, suggesting that there are other mechanisms that may confer resistance to this drug.

Methods

We performed whole-genome sequencing on 121 H. pylori clinical strains, among which 73 were metronidazole-resistant. Sequence-alignment analysis of core protein clusters derived from clinical strains containing full-length RdxA was performed. Variable sites in each alignment were statistically compared between the resistant and susceptible groups to determine candidate genes along with their respective amino-acid changes that may account for the development of metronidazole resistance in H. pylori.

Results

Resistance due to RdxA truncation was identified in 34% of metronidazole-resistant strains. Analysis of core protein clusters derived from the remaining 48 metronidazole-resistant strains and 48 metronidazole-susceptible identified four variable sites significantly associated with metronidazole resistance. These sites included R16H/C in RdxA, D85N in the inner-membrane protein RclC (HP0565), V265I in a biotin carboxylase protein (HP0370) and A51V/T in a putative threonylcarbamoyl–AMP synthase (HP0918).

Conclusions

Our approach identified new potential mechanisms for metronidazole resistance in H. pylori that merit further investigation.

The microbiome and lung cancer

It has become increasingly clear that we live in a symbiotic relationship with microbes within us. We are just beginning to unravel the nature and strength of this relationship and its impact on both physiology and by extension, pathology. While microorganisms have long been known to have carcinogenic potential, their role may have been underestimated. The knowledge of the role of the microbiome in carcinogenesis is rapidly evolving. This evolution has reached a tipping point with current omics technologies used for cataloguing the microbiome. The lung is an organ constantly exposed to the environment. It is now clear that the lung has a distinct microbiome and that this may influence the development of lung cancer. In addition, evidence suggests that this microbiome originates from the oral microbiome. This review summarizes current knowledge about the role of microbiome, especially the oral and lung microbiome in human lung cancer. The goal of the manuscript is to provide a summary of this rapidly evolving field while providing a context of the general role of the microbiome in carcinogenesis. In addition, a primer of the current technology used in evaluating the microbiome is provided to familiarize the practicing clinician with the experimental methods used to generate the information that will likely impact the field of lung cancer.

CoreProbe: A Novel Algorithm for Estimating Relative Abundance Based on Metagenomic Reads

With the rapid development of high-throughput sequencing technology, the analysis of metagenomic sequencing data and the accurate and efficient estimation of relative microbial abundance have become important ways to explore the microbial composition and function of microbes. In addition, the accuracy and efficiency of the relative microbial abundance estimation are closely related to the algorithm and the selection of the reference sequence for sequence alignment. We introduced the microbial core genome as the reference sequence for potential microbes in a metagenomic sample, and we constructed a finite mixture and latent Dirichlet models and used the Gibbs sampling algorithm to estimate the relative abundance of microorganisms. The simulation results showed that our approach can improve the efficiency while maintaining high accuracy and is more suitable for high-throughput metagenomic data. The new approach was implemented in our CoreProbe package which provides a pipeline for an accurate and efficient estimation of the relative abundance of microbes in a community. This tool is available free of charge from the CoreProbe's website: Access the Docker image with the following instruction: sudo docker pull panhongfei/coreprobe:1.0.

Treatment of Helicobacter pylori infected mice with Bryophyllum pinnatum, a medicinal plant with antioxidant and antimicrobial properties, reduces bacterial load

CONTEXT

Bryophyllum pinnatum (Lam.) Kurz (Crassulaceae) is a plant known for its antiulcer properties.

OBJECTIVE

This study evaluates the anti-Helicobacter pylori activity of Bryophyllum pinnutum methanol extract with a mouse model and its antioxidant properties.

MATERIALS AND METHODS

Dried leaves of Bryophyllum pinnutum were extracted with methanol and ethyl acetate. Broth microdilution method was used to evaluate the anti-Helicobacter activity of extract samples in vitro. Swiss mice were inoculated with a suspension of Helicobacter pylori and divided into control group and four others that received 125, 250, 500 mg/kg of methanol extract or ciprofloxacin (500 mg/kg), respectively, for 7 days. Helicobacter pylori colonization and bacterial load of mouse stomach was assessed on day 1 and 7 post-treatment. The antioxidant activity of Bryophyllum pinnutum was evaluated through DPPH radical, hydroxyl radical and reducing power assay.

RESULTS

Methanol extract showed a significant anti-Helicobacter activity with MIC and MBC values of 32 and 256 μg/mL, respectively. Bryophyllum pinnatum and ciprofloxacin reduced H. pylori colonization of gastric tissue from 100% to 17%. Bryophyllum pinnatum extract (85.91 ± 52.91 CFU) and standard (25.74 ± 16.15 CFU) also reduced significantly (p < 0.05) bacterial load of gastric mucosa as compared to untreated infected mice (11883 ± 1831 CFU). DPPH radical, hydroxyl radical and reducing power assays showed IC₅₀ values of 25.31 ± 0.34, 55.94 ± 0.68 and 11.18 ± 0.74 μg/mL, respectively.

DISCUSSION AND CONCLUSION

The data suggest that the methanol extract of Bryophyllum pinnatum could inhibit Helicobacter pylori growth, and may also acts as an antioxidant to protect gastric mucosa against reactive oxygen species.

Quantum changes in Helicobacter pylori gene expression accompany host-adaptation

Helicobacter pylori is a highly successful gastric pathogen. High genomic plasticity allows its adaptation to changing host environments. Complete genomes of H. pylori clinical isolate UM032 and its mice-adapted serial derivatives 298 and 299, generated using both PacBio RS and Illumina MiSeq sequencing technologies, were compared to identify novel elements responsible for host-adaptation. The acquisition of a jhp0562-like allele, which encodes for a galactosyltransferase, was identified in the mice-adapted strains. Our analysis implies a new β-1,4-galactosyltransferase role for this enzyme, essential for Le^y antigen expression. Intragenomic recombination between babA and babB genes was also observed. Further, we expanded on the list of candidate genes whose expression patterns have been mediated by upstream homopolymer-length alterations to facilitate host adaption. Importantly, greater than four-fold reduction of mRNA levels was demonstrated in five genes. Among the down-regulated genes, three encode for outer membrane proteins, including BabA, BabB and HopD. As expected, a substantial reduction in BabA protein abundance was detected in mice-adapted strains 298 and 299 via Western analysis. Our results suggest that the expression of Le^y antigen and reduced outer membrane protein expressions may facilitate H. pylori colonisation of mouse gastric epithelium.

Selye's general adaptation syndrome: stress-induced gastro-duodenal ulceration and inflammatory bowel disease

Hans Selye in a note to Nature in 1936 initiated the field of stress research by showing that rats exposed to nocuous stimuli responded by way of a 'general adaptation syndrome' (GAS). One of the main features of the GAS was the 'formation of acute erosions in the digestive tract, particularly in the stomach, small intestine and appendix'. This provided experimental evidence for the view based on clinical data that gastro-duodenal (peptic) ulcers could be caused by stress. This hypothesis was challenged by Marshall and Warren's Nobel Prize (2005)-winning discovery of a causal association between Helicobacter pylori and peptic ulcers. However, clinical and experimental studies suggest that stress can cause peptic ulceration in the absence of H. pylori Predictably, the etiological pendulum of gastric and duodenal ulceration has swung from 'all stress' to 'all bacteria' followed by a sober realization that both factors play a role, separately as well as together. This raises the question as to whether stress and H. pylori interact, and if so, how? Stress has also been implicated in inflammatory bowel disease (IBD) and related disorders; however, there is no proof yet that stress is the primary etiological trigger for IBD. Central dopamine mechanisms seem to be involved in the stress induction of peptic ulceration, whereas activation of the sympathetic nervous system and central and peripheral corticotrophin-releasing factor appears to mediate stress-induced IBD.

Historical Perspective on Familial Gastric Cancer

Gastric cancer is a common disease worldwide, typically associated with acquired chronic inflammation in the stomach, related in most instances to infection by Helicobacter pylori. A small percentage of cases occurs in familial clusters, and some of these can be linked to specific germline mutations. This article reviews the historical background to the current understanding of familial gastric cancer, focuses on the entity of hereditary diffuse gastric cancer, and also reviews the risks for gastric cancer related to a number of other familial genetic diseases.

Julian Davies and the discovery of kanamycin resistance transposon Tn5

This paper recounts some of my fond memories of a collaboration between Julian Davies and myself that started in 1974 in Geneva and that led to our serendipitous discovery of the bacterial kanamycin resistance transposon Tn5, and aspects of the lasting positive impact of our interaction and discovery on me and the community. Tn5 was one of the first antibiotic resistance transposons to be found. Its analysis over the ensuing decades provided valuable insights into mechanisms and control of transposition, and led to its use as a much-valued tool in diverse areas of molecular genetics, as also will be discussed here.

Radiation therapy for gastric mucosa-associated lymphoid tissue lymphoma: dose-volumetric analysis and its clinical implications

Purpose

To assess the clinical outcomes of radiotherapy (RT) using two-dimensional (2D) and three-dimensional conformal RT (3D-CRT) for patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma to evaluate the effectiveness of involved field RT with moderate-dose and to evaluate the benefit of 3D-CRT comparing with 2D-RT.

Materials and Methods

Between July 2003 and March 2015, 33 patients with stage IE and IIE gastric MALT lymphoma received RT were analyzed. Of 33 patients, 17 patients (51.5%) were Helicobacter pylori (HP) negative and 16 patients (48.5%) were HP positive but refractory to HP eradication (HPE). The 2D-RT (n = 14) and 3D-CRT (n = 19) were performed and total dose was 30.6 Gy/17 fractions. Of 11 patients who RT planning data were available, dose-volumetric parameters between 2D-RT and 3D-CRT plans was compared.

Results

All patients reached complete remission (CR) eventually and median time to CR was 3 months (range, 1 to 15 months). No local relapse occurred and one patient died with second primary malignancy. Tumor response, survival, and toxicity were not significantly different between 2D-RT and 3D-CRT (p > 0.05, each). In analysis for dose-volumetric parameters, D_max and CI for PTV were significantly lower in 3D-CRT plans than 2D-RT plans (p < 0.05, each) and D_mean and V₁₅ for right kidney and D_mean for left kidney were significantly lower in 3D-CRT than 2D-RT (p < 0.05, each).

Conclusion

Our data suggested that involved field RT with moderate-dose for gastric MALT lymphoma could be promising and 3D-CRT could be considered to improve the target coverage and reduce radiation dose to the both kidneys.

Aggravation of Helicobacter pylori stomach infections in stressed military recruits

Objective

To investigate the effect of military stress on immune response and Helicobacter pylori stomach infections.

Methods

In this prospective, observational study, the Symptom Checklist-90 questionnaire was completed by military recruits before and following a 3-month basic training programme. H. pylori immunoglobulin (Ig)G levels, C¹⁴-urea breath-test values and levels of cortisol, catecholamine, and certain humoral and cellular immune responses were measured before and after the basic training.

Results

For 60 military recruits, somatization, depression and paranoid ideation scores were significantly increased after, compared with before, basic training. Post-training H. pylori IgG detection revealed three additional cases of H. pylori infection. Post-training C¹⁴-urea breath-test values were significantly higher compared with before training – thus suggesting higher levels of H. pylori colonization in the stomach. Post-training cortisol and catecholamine levels were increased, while serum IgG levels were decreased; complement component (C)3 and C4 levels remained unchanged. Post-training CD4⁺ and CD8⁺ T-cell percentages and the CD4⁺/CD8⁺ ratio were significantly reduced compared with before training. Serum interleukin (IL)-2 levels were lower and IL-10 levels were higher following training and there was a significant decrease in the IL-2/IL-10 ratio.

Conclusion

Military stress may reduce humoral and cellular immune responses and may aggravate the severity of H. pylori infection.

Fucoidans Disrupt Adherence of Helicobacter pylori to AGS Cells In Vitro

Fucoidans are complex sulphated polysaccharides derived from abundant and edible marine algae. Helicobacter pylori is a stomach pathogen that persists in the hostile milieu of the human stomach unless treated with antibiotics. This study aims to provide preliminary data to determine, in vitro, if fucoidans can inhibit the growth of H. pylori and its ability to adhere to gastric epithelial cells (AGS). We analysed the activity of three different fucoidan preparations (Fucus A, Fucus B, and Undaria extracts). Bacterial growth was not arrested or inhibited by the fucoidan preparations supplemented into culture media. All fucoidans, when supplemented into tissue culture media at 1000 µg mL(-1), were toxic to AGS cells and reduced the viable cell count significantly. Fucoidan preparations at 100 µg mL(-1) were shown to significantly reduce the number of adherent H. pylori. These in vitro findings provide the basis for further studies on the clinical use of sulphated polysaccharides as complementary therapeutic agents.

Detection of gastric precancerous conditions in daily clinical practice: a nationwide survey

BACKGROUND

The burden of gastric precancerous conditions and factors associated with their detection have not been fully investigated in community-based settings. Little is known about adherence to Sydney system for histopathology of gastric biopsies.

OBJECTIVE

We aimed to investigate what really happens in clinical practice with regard to the detection of gastric atrophy and intestinal metaplasia in dyspeptic patients.

METHODS

We performed a nationwide survey of 979 consecutive patients (50-65 years old) with dyspeptic symptoms, examined at 24 gastrointestinal endoscopy units throughout Italy. Clinical information was collected from questionnaires; a standard bioptic mapping was performed in each unit, biopsies from each patient were analyzed by histopathology performed according to daily clinical practice in each local histopathology center.

RESULTS

Separate descriptions of antral and corporal biopsies were included in 679 pathology reports (69%), whereas Sydney system was applied in 324 reports (33%). Gastric atrophy without intestinal metaplasia (GA) and gastric atrophy with intestinal metaplasia (GIM) were detected in 322 (33%) patients. The full adherence to Sydney system significantly increased the probability of detecting GIM (OR 9.6, 95% CI 5.5-16.7), GA (OR 1.92, 95% CI 1.07-3.44), and either of the conditions (OR 6.67, 95% CI 4.36-10.19).

CONCLUSIONS

This nationwide survey showed that in one-third of dyspeptic patients, gastric precancerous conditions are detected. In daily routine practice, only 1/3 of histology reports were worked out adhering to Sydney system showing that international guidelines are poorly observed in clinical practice. This may represent a critical element for surveillance strategies for gastric cancer.

No human protein is exempt from bacterial motifs, not even one

The hypothesis that mimicry between a self and a microbial peptide antigen is strictly related to autoimmune pathology remains a debated concept in autoimmunity research. Clear evidence for a causal link between molecular mimicry and autoimmunity is still lacking. In recent studies we have demonstrated that viruses and bacteria share amino acid sequences with the human proteome at such a high extent that the molecular mimicry hypothesis becomes questionable as a causal factor in autoimmunity. Expanding upon our analysis, here we detail the bacterial peptide overlapping to the human proteome at the penta-, hexa-, hepta- and octapeptide levels by exact peptide matching analysis and demonstrate that there does not exist a single human protein that does not harbor a bacterial pentapeptide or hexapeptide motif. This finding suggests that molecular mimicry between a self and a microbial peptide antigen cannot be assumed as a basis for autoimmune pathologies. Moreover, the data are discussed in relation to the microbial immune escape phenomenon and the possible vaccine-related autoimmune effects.

Association between Helicobacter pylori genotypes and severity of chronic gastritis, peptic ulcer disease and gastric mucosal interleukin-8 levels: Evidence from a study in the Middle East

Background

The varied clinical presentations of Helicobacter pylori (H. pylori) infection are most likely due to differences in the virulence of individual strains, which determines its ability to induce production of interleukin-8 (IL-8) in the gastric mucosa. The aim of this study was to examine association between cagA, vacA-s1 and vacA-s2 genotypes of H. pylori and severity of chronic gastritis and presence of peptic ulcer disease (PUD), and to correlate these with IL-8 levels in the gastric mucosa.

Methods

Gastric mucosal biopsies were obtained from patients during esophagogastroduodenoscopy. The severity of chronic gastritis was documented using the updated Sydney system. H. pylori cagA and vacA genotypes were detected by PCR. The IL-8 levels in the gastric mucosa were measured by ELISA.

Results

H. pylori cagA and/or vacA genotypes were detected in 99 patients (mean age 38.4±12.9; 72 males), of whom 52.5% were positive for cagA, 44.4% for vacA-s1 and 39.4% for vacA-s2; and 70.7% patients had PUD. The severity of inflammation in gastric mucosa was increased with vacA-s1 (p=0.017) and decreased with vacA-s2 (p=0.025), while cagA had no association. The degree of neutrophil activity was not associated with either cagA or vacA-s1, while vacA-s2 was significantly associated with decreased neutrophil activity (p=0.027). PUD was significantly increased in patients with cagA (p=0.002) and vacA-s1 (p=0.031), and decreased in those with vacA-s2 (p=0.011). The level of IL-8 was significantly increased in patients with cagA (p=0.011) and vacA-s1 (p=0.024), and lower with vacA-s2 (p=0.004). Higher levels of IL-8 were also found in patients with a more severe chronic inflammation (p=0.001), neutrophil activity (p=0.007) and those with PUD (p=0.001).

Conclusions

Presence of vacA-s1 genotype of H. pylori is associated with more severe chronic inflammation and higher levels of IL-8 in the gastric mucosa, as well as higher frequency of PUD. Patients with vacA-s2 have less severe gastritis, lower levels of IL-8, and lower rates of PUD. The presence of cagA genotype is not associated with the severity of gastritis or IL-8 induction in the gastric mucosa. The association of cagA with PUD may be a reflection of its presence with vacA-s1 genotype.

Helicobacter pylori in vegetables and salads: genotyping and antimicrobial resistance properties

From a clinical and epidemiological perspective, it is important to know which genotypes and antibiotic resistance patterns are present in H. pylori strains isolated from salads and vegetables. Therefore, the present investigation was carried out to find this purpose. Three hundred eighty washed and unwashed vegetable samples and fifty commercial and traditional salad samples were collected from Isfahan, Iran. Samples were cultured and those found positive for H. pylori were analyzed using PCR. Antimicrobial susceptibility testing was performed using disk diffusion method. Seven out of 50 (14%) salad and 52 out of 380 (13.68%) vegetable samples harbored H. pylori. In addition, leek, lettuce, and cabbage were the most commonly contaminated samples (30%). The most prevalent virulence genes were oipA (86.44%) and cagA (57.625). VacA s1a (37.28%) and iceA1 (47.45%) were the most prevalent genotypes. Forty different genotypic combinations were recognized. S1a/cagA+/iceA1/oipA+ (33.89%), s1a/cagA+/iceA2/oipA (30.50%), and m1a/cagA+/iceA1/oipA+ (28.81%) were the most prevalent combined genotypes. Bacterial strains had the highest levels of resistance against metronidazole (77.96%), amoxicillin (67.79%), and ampicillin (61.01%). High similarity in the genotyping pattern of H. pylori among vegetable and salad samples and human specimens suggests that vegetable and salads may be the sources of the bacteria.

Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori

Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide), (-)-epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L) was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L). The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain), clarithromycin (49.8 mg/L for PED 3582GA strain), metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain), or tetracycline (14.2 mg/L for B strain) was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0). DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h). The Western blot analysis revealed that urease subunits (UreA and UreB) of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (-)-epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

Levofloxacin and proton pump inhibitor-based triple therapy versus standard triple first-line therapy for Helicobacter pylori eradication

BACKGROUND

Standard triple therapy for Helicobacter pylori infection fails in up to one quarter of patients. Levofloxacin-based triple therapy may be more efficacious.

OBJECTIVE

The aim of this paper was to compare levofloxacin and proton pump inhibitor-based triple therapy with standard triple therapy for H. pylori infection.

METHODS

PubMed, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Google Scholar, and Ovid were systematically searched to identify randomized controlled trials comparing levofloxacin and proton pump inhibitor-based therapy with standard triple therapy in treatment-naive patients with H. pylori infection until August 2013.

RESULTS

Ten randomized controlled trials involving 2676 patients (1357 in the levofloxacin group and 1319 in the control group) met the inclusion criteria. The pooled odds ratio by intention-to-treat analysis and by per protocol analysis in the levofloxacin regimen versus standard regimen was 1.28 [95% confidence interval (CI): 0.88-1.85] and 1.23 (95% CI: 0.82-1.84) by the random effects model, respectively. There was no statistical significance of the incidence of total side effects between the groups, but levofloxacin-based therapy was associated with a significant reduction in the incidence of taste disturbance compared with standard third therapy.

CONCLUSION

Levofloxacin-based therapy was as safe and effective as triple therapy for H. pylori infection and could be considered as an additional treatment option. However, more rigorous research is required to accurately assess the role of levofloxacin in eradicating H. pylori infection.

The role of radiotherapy in the treatment of gastric mucosa-associated lymphoid tissue lymphoma

Purpose

To assess radiotherapy for patients with early stage gastric mucosa-associated lymphoid tissue (MALT) lymphoma with respect to survival, treatment response, and complications.

Materials and Methods

Enrolled into this study were 48 patients diagnosed with gastric MALT lymphoma from January 2000 to September 2012. Forty-one patients had low grade and seven had mixed component with high grade. Helicobacter pylori eradication was performed in 33 patients. Thirty-four patients received radiotherapy alone. Ten patients received chemotherapy before radiotherapy, and three patients underwent surgery followed by chemotherapy and radiotherapy. One patient received surgery followed by radiotherapy. All patients received radiotherapy of median dose of 30.6 Gy.

Results

The duration of follow-up ranged from 6 to 158 months (median, 48 months). Five-year overall survival and cause-specific survival rates were 90.3% and 100%. All patients treated with radiotherapy alone achieved pathologic complete remission (pCR) in 31 of the low-grade and in three of the mixed-grade patients. All patients treated with chemotherapy and/or surgery prior to radiotherapy achieved pCR except one patient who received chemotherapy before radiotherapy. During the follow-up period, three patients developed diffuse large B-cell lymphoma in the stomach, and one developed gastric adenocarcinoma after radiotherapy. No grade 3 or higher acute or late complications developed. One patient, who initially exhibited gastroptosis, developed mild atrophy of left kidney.

Conclusion

These findings indicate that a modest dose of radiotherapy alone can achieve a high cure rate for low-grade and even mixed-grade gastric MALT lymphoma without serious toxicity. Patients should be carefully observed after radiotherapy to screen for secondary malignancies.

Epstein-Barr virus and gastric cancer

Gastric cancer ranks second among malignancies in terms of global incidence. Epstein-Barrvirus (EBV)-associated gastric carcinoma (EBVaGC) is a recently recognized entity, which is defined by the presence of EBV in gastric carcinoma cells. EBVaGC represents about 10% of gastric carcinoma cases worldwide. It is estimated that there are over 80000 new EBVaGC cases in the world annually. EBVaGC shows some distinct clinical and pathological characteristics. The observation that EBV-encoded small RNA is expressed in cancer cells but not in surrounding normal epithelial cells strongly suggests that EBV plays an etiological role in gastric carcinogenesis. In this review, we discuss the relationship between EBV and gastric carcinogenesis.

Exploitation of eukaryotic subcellular targeting mechanisms by bacterial effectors

Several bacterial species have evolved specialized secretion systems to deliver bacterial effector proteins into eukaryotic cells. These effectors have the capacity to modulate host cell pathways in order to promote bacterial survival and replication. The spatial and temporal context in which the effectors exert their biochemical activities is crucial for their function. To fully understand effector function in the context of infection, we need to understand the mechanisms that lead to the precise subcellular localization of effectors following their delivery into host cells. Recent studies have shown that bacterial effectors exploit host cell machinery to accurately target their biochemical activities within the host cell.