The infection connection. Helicobacter pylori is more than just the cause of gastric ulcers--it offers an unprecedented opportunity to study changes in human microecology and the nature of chronic disease

Treatment of Helicobacter pylori Is Not Associated With Future Clostridium difficile Infection

INTRODUCTION

Helicobacter pylori (HP) infection is associated with many gastrointestinal disorders, including gastric cancer, and consensus guidelines recommend eradication after detection. There is a theoretical, yet uninvestigated, concern that HP treatment could increase the risk of Clostridium difficile infection (CDI). Using the data from a large cohort of patients with HP, we investigated whether HP eradication is associated with CDI.

METHODS

A retrospective cohort study within the Veterans Health Administration on 38,535 patients (median age 61.8 years; 91.8% men) with detected HP between January 1, 1994, and December 31, 2018 was conducted. Primary outcome was a positive laboratory test for CDI within 3 months of HP detection. Multivariable logistic regression evaluated the following: patient demographics, previous CDI, recent hospitalization, and whether the patient received HP eradication therapy (by antibiotic and regimen, and including proton pump therapy). Secondary analysis of those treated evaluated whether eradication of HP was associated with CDI.

RESULTS

Among 38,535 patients, 28,818 (74.8%) were treated for HP and 284 (0.74%) developed CDI. In multivariable analysis, prominent factors included hospital discharge within 12 weeks (odds ratio [OR] 2.15; 95% confidence interval [CI]: 1.22-3.77) and 4 weeks (OR 3.46; 95% CI: 2.18-5.48), P < 0.001, and previous CDI (OR 12.5; 95% CI: 9.21-17.0, P < 0.001). Treatment of HP was not associated with future CDI. In secondary analysis of those treated, confirmation of eradication was not associated with future CDI (OR 1.49; 95% CI: 0.67-3.29).

DISCUSSION

In a large study of US patients with HP, we demonstrate that neither treatment nor eradication of HP is associated with CDI. Previous C. difficile infection and recent hospital discharge, established risk factors for CDI, are strongly associated. These findings suggest that treatment should be continued to be prescribed when HP is detected (http://links.lww.com/AJG/B507).

Oesophageal and proximal gastric adenocarcinomas are rare after detection of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection is the most important risk factor for non-proximal gastric adenocarcinoma, yet some posit it is protective against oesophageal adenocarcinoma and proximal gastric cancers.

AIMS

To evaluate the incidence of and risk factors for future oesophageal and proximal gastric cancers, utilizing the largest North American cohort of patients with previously identified H pylori. Also to identify whether treatment and eradication of H pylori alter future oesophageal and proximal gastric cancer risk.

METHODS

Retrospective cohort study within the Veterans Administration of 36 803 patients (median age 60.4 years; 91.8% male) with confirmed H pylori between 01 January 1994 and 31 December 2018. Primary outcome was diagnosis of future oesophageal and proximal gastric cancers. A time to event with competing risk analysis was performed, evaluating patient factors and whether the patient received H pylori treatment. Secondary analysis of those treated evaluated whether confirmed eradication was associated with cancer.

RESULTS

The cumulative incidence of oesophageal and proximal gastric cancers 5, 10 and 15 years after H pylori detection was 0.145%, 0.26% and 0.34%. Risk of future oesophageal or proximal gastric cancer was similar amongst whites (reference), African Americans (SHR 0.87, 95%CI 0.57-1.43) and American Indians (SHR 1.31, 95%CI 0.18-9.60) but substantially reduced in those of Asian (no cases amongst 213 H pylori positive) or native Hawaiian origin (no cases amongst 295 H pylori positive) (P < .001). Increasing age (SHR 1.17 per 5 years, 95% CI: 1.09-1.25, P < 0.001) and smoking (SHR 2.06, 95% CI: 1.33-3.18, P = 0.001) were associated with oesophageal and proximal gastric cancers. Neither treatment of H pylori nor eradication status were associated with cancer (P > 0.20).

CONCLUSIONS

In the largest study of US patients with H pylori, we demonstrate that rates of oesophageal and proximal gastric cancers after treatment of H pylori are low. Older age, and smoking are associated with future cancer, whilst Asian or Native Hawaiian race are protective. H pylori treatment and eradication are not associated with future cancer.

Risk Factors and Incidence of Gastric Cancer After Detection of Helicobacter pylori Infection: A Large Cohort Study

BACKGROUND & AIMS

Nearly all studies of gastric adenocarcinoma in the United States have relied on national cancer databases, which do not include data on Helicobacter pylori infection, the most well-known risk factor for gastric cancer. We collected data from a large cohort of patients in the United States to calculate the incidence of and risk factors for nonproximal gastric adenocarcinomas after detection of H pylori. Secondary aims included identifying how treatment and eradication affect cancer risk.

METHODS

We performed a retrospective cohort study, collecting data from the Veterans Health Administration on 371,813 patients (median age 62 years; 92.3% male) who received a diagnosis of H pylori infection from January 1, 1994, through December 31, 2018. The primary outcome was a diagnosis of distal gastric adenocarcinoma 30 days or more after detection of H pylori infection. We performed a time to event with competing risk analysis (with death before cancer as a competing risk).

RESULTS

The cumulative incidence of cancer at 5, 10, and 20 years after detection of H pylori infection was 0.37%, 0.5%, and 0.65%, respectively. Factors associated with cancer included older age at time of detection of H pylori infection (subhazard ratio [SHR], 1.13; 95% confidence interval [CI], 1.11-1.15; P < .001), black/African American race (SHR, 2.00; 95% CI, 1.80-2.22), Asian race (SHR, 2.52; 95% CI, 1.64-3.89) (P < .001 for race), Hispanic or Latino ethnicity (SHR, 1.59; 95% CI, 1.34-1.87; P < .001), and history of smoking (SHR, 1.38; 95% CI, 1.25-1.52; P < .001). Women had decreased risk of gastric adenocarcinoma compared with men (SHR, 0.52; 95% CI, 0.40-0.68; P < .001); patients whose H pylori infection was detected based on serum antibody positivity also had a reduced risk of cancer (SHR 0.74; 95% CI, 0.54-1.04; P = .04). Patients who received treatment for their H pylori infection still had an increased risk of gastric cancer (SHR, 1.16; 95% CI, 0.74-1.83; P = .51) but confirmed H pylori eradication after treatment reduced risk of gastric cancer (SHR, 0.24; 95% CI, 0.15-0.41; P < .001).

CONCLUSIONS

In a study of 371,813 veterans with a diagnosis of H pylori infection, we found significantly higher risks of gastric cancer in racial and ethnic minorities and smokers. Treatment of H pylori infection decreased risk only if eradication was successful. Studies are needed on the effects of screening high-risk persons and to identify quality measures for diagnosis, resistance patterns, and treatment efficacy.

Ancient human microbiomes

Very recently, we discovered a vast new microbial self: the human microbiome. Our native microbiota interface with our biology and culture to influence our health, behavior, and quality of life, and yet we know very little about their origin, evolution, or ecology. With the advent of industrialization, globalization, and modern sanitation, it is intuitive that we have changed our relationship with microbes, but we have little information about the ancestral state of our microbiome, and we therefore lack a foundation for characterizing this change. High-throughput sequencing has opened up new opportunities in the field of paleomicrobiology, allowing us to investigate the evolution of the complex microbial ecologies that inhabit our bodies. By focusing on recent coprolite and dental calculus research, we explore how emerging research on ancient human microbiomes is changing the way we think about ancient disease and how archaeological studies can contribute to a medical understanding of health and nutrition today.

Helicobacter pylori genetic diversity and gastro-duodenal diseases in Malaysia

Helicobacter pylori infection results in diverse clinical conditions ranging from chronic gastritis and ulceration to gastric adenocarcinoma. Among the multiethnic population of Malaysia, Indians consistently have a higher H. pylori prevalence as compared with Chinese and Malays. Despite the high prevalence of H. pylori, Indians have a relatively low incidence of peptic ulcer disease and gastric cancer. In contrast, gastric cancer and peptic ulcer disease incidence is high in Chinese. H. pylori strains from Chinese strains predominantly belong to the hspEAsia subpopulation while Indian/Malay strains mainly belong to the hspIndia subpopulation. By comparing the genome of 27 Asian strains from different subpopulations, we identified six genes associated with risk of H. pylori-induced peptic ulcer disease and gastric cancer. This study serves as an important foundation for future studies aiming to understand the role of bacterial factors in H. pylori-induced gastro-duodenal diseases.

Chlamydia pneumoniae infection in adolescents with type 1 diabetes mellitus

Chlamydia pneumoniae, an intracellular bacterium, is associated with respiratory diseases, reinfectivity and chronic diseases such as cardiovascular disease, hypertension and stroke. The risk of infection is higher and infections are a serious clinical problem in patients with type 1 (insulin-dependent) diabetes mellitus (T1DM). Although diabetes mellitus and hyperglycaemia are considered possible risk factors for various types of aetiological agents, the epidemiological evidence concerning C. pneumoniae infection is scanty. The aim of the present study was to evaluate the impact of glycosylated haemoglobin (HbA1c) levels, an indicator of a hyperglycaemic state, on C. pneumoniae infection and disease chronicity; in addition we compared the duration of diabetes with the occurrence of C. pneumoniae infection. C. pneumoniae blood real time PCR and serology (IgG, IgA and IgM) assays by an ELISA method were performed. C. pneumoniae DNA was detected in 46.5 % [95 % confidence interval (CI) = 35.1-57.9 %] of the patients with T1DM; this prevalence is higher (P<0.05) than in non-diabetic paediatric controls, 10.5 % (95 % CI = 3.6-17.4 %). IgG/IgA C. pneumoniae antibody positivity was significantly (P≤0.05) more common in patients in poor metabolic control (HbA1c >9 %) versus patients in good metabolic control (HbA1c <7 %), suggesting that the metabolic control of the disease is compromised in the patients with T1DM. In conclusion, adolescents with T1DM were more likely to show signs of infection with C. pneumoniae compared with healthy adolescents and the results suggest an increased risk of progressing from an acute C. pneumoniae infection to a chronic form.

NLRP3 inflammasome is a target for development of broad-spectrum anti-infective drugs

We describe the molecular mode of action and pharmacodynamics of a new molecular entity (NME) that induces the NLRP3 inflammasome-mediated innate immune response. This innate response reduces the pathogen load in an experimentally induced methicillin-resistant Staphylococcos aureus infection, enhances survival in an experimentally induced Gram-negative bacteremia, and overrides the escape mechanism of an obligate intracellular pathogen, viz. Chlamydia pneumoniae. Furthermore, the NME is more effective than standard-of-care antibiotic therapy in a clinically established multifactorial bacterial infection. Analysis of transcriptional regulation of inflammasome signaling genes and innate/adaptive immune genes revealed consistent and significant host changes responsible for the improved outcomes in these infections. These studies pave the way for the development of first-in-class drugs that enhance inflammasome-mediated pathogen clearance and identify the NLRP3 inflammasome as a drug target to address the global problem of emerging new infectious diseases and the reemergence of old diseases in an antibiotic-resistant form.

Metabolomics: towards understanding host-microbe interactions

Metabolomics employs an array of analytical techniques, including high-resolution nuclear magnetic resonance spectroscopy and mass spectrometry, to simultaneously analyze hundreds to thousands of small-molecule metabolites in biological samples. In conjunction with chemoinformatics and bioinformatics tools, metabolomics enables comprehensive characterization of the metabolic phenotypes (metabotypes) of the human, and other mammalian, hosts that have co-evolved with a large number of diverse commensal microbes, especially in the intestinal tract. Correlation of the metabotypes with the microbial profiles derived from culture-independent molecular techniques is increasingly helping to decipher inherent and intimate host-microbe relationships. This integrated, systems biology approach is improving our understanding of the molecular mechanisms underlying multilevel host-microbe interactions, and promises to elucidate the etiologies of human disorders resulting from unfavorable human-microbial associations, including enteric infections.

A review of co-morbidity between infectious and chronic disease in Sub Saharan Africa: TB and diabetes mellitus, HIV and metabolic syndrome, and the impact of globalization

Background

Africa is facing a rapidly growing chronic non-communicable disease burden whilst at the same time experiencing continual high rates of infectious disease. It is well known that some infections increase the risk of certain chronic diseases and the converse. With an increasing dual burden of disease in Sub Saharan Africa the associations between diseases and our understanding of them will become of increased public health importance.

Aims

In this review we explore the relationships reported between tuberculosis and diabetes mellitus, human immunodeficiency virus, its treatment and metabolic risk. We aimed to address the important issues surrounding these associations within a Sub Saharan African setting and to describe the impact of globalization upon them.

Findings

Diabetes has been associated with a 3-fold incident risk of tuberculosis and it is hypothesised that tuberculosis may also increase the risk of developing diabetes. During co-morbid presentation of tuberculosis and diabetes both tuberculosis and diabetes outcomes are reported to worsen. Antiretroviral therapy for HIV has been associated with an increased risk of developing metabolic syndrome and HIV has been linked with an increased risk of developing both diabetes and cardiovascular disease. Globalization is clearly related to an increased risk of diabetes and cardiovascular disease. It may be exerting other negative and positive impacts upon infectious and chronic non-communicable disease associations but at present reporting upon these is sparse.

Conclusion

The impact of these co-morbidities in Sub Saharan Africa is likely to be large. An increasing prevalence of diabetes may hinder efforts at tuberculosis control, increasing the number of susceptible individuals in populations where tuberculosis is endemic, and making successful treatment harder. Roll out of anti-retroviral treatment coverage within Sub Saharan Africa is an essential response to the HIV epidemic however it is likely to lead to a growing number of individuals suffering adverse metabolic consequences. One of the impacts of globalization is to create environments that increase both diabetes and cardiovascular risk but further work is needed to elucidate other potential impacts. Research is also needed to develop effective approaches to reducing the frequency and health impact of the co-morbidities described here.

Lactobacilli inhibit interleukin-8 production induced by Helicobacter pylori lipopolysaccharide-activated Toll-like receptor 4

AIM: To investigate the effect of Lactobacillus bulgaricus (LBG) on the Toll-like receptor 4 (TLR4) pathway and interleukin-8 (IL-8) production in SGC-7901 cells treated with Helicobacter pyloriSydney strain 1 lipopolysaccharide (H pyloriSS1-LPS).

METHODS: SGC-7901 cells were treated with H pyloriSS1-LPS in the presence or absence of pretreatment for 1 h with viable LBG or supernatant recovered from LBG culture MRS broth (LBG-_S). Cellular lysates were prepared for Western blot with anti-TLR4, anti-transforming growth factor β-activated kinase 1 (TAK1), anti-phospho-TAK1, anti-nuclear factor κB (NF-κB), anti-p38 mitogen-activated protein kinase (p38MAPK), and anti-phospho-p38MAPK antibodies. The amount of IL-8 in cell culture medium was measured by ELISA.

RESULTS: H pyloriSS1-LPS up-regulated the expression of TLR4, stimulated the phosphorylation of TAK1, subsequently enhanced the activation of NF-κB and the phosphorylation of p38MAPK in a time-dependent manner, leading to augmentation of IL-8 production in SGC-7901 cells. Viable LBG or LBG-_S pretreatment attenuated the expression of TLR4, inhibited the phosphorylation of TAK1 and p38MAPK, prevented the activation of NF-κB, and consequently blocked IL-8 production.

CONCLUSION: H pyloriSS1-LPS induces IL-8 production through activating TLR4 signaling in SGC-7901 cells and viable LBG or LBG-_S prevents H pyloriSS1-LPS-mediated IL-8 production via inhibition of the TLR4 pathway.