Force of infection of Helicobacter pylori in Mexico: evidence from a national survey using a hierarchical Bayesian model

Prevalence and resistance of Helicobacter pylori in a predominantly Hispanic population

BACKGROUND

Helicobacter pylori (H. pylori) is the most common chronic bacterial infection in humans. The risk of acquiring H. pylori is related to socioeconomic status and living conditions early in life. Treatment regimens must consider local antibiotic resistance patterns. Adventist Health White Memorial Hospital serves a predominantly indigent population in east Los Angeles with a large number of immigrants from South and Central America. Data regarding the prevalence and resistance of H. pylori in this population is scant.

AIM

To evaluate the prevalence and resistance of H. pylori and correlate with country of origin.

METHODS

All gastric biopsies were obtained by a single gastroenterologist at the hospital in a consecutive manner from patients with gastritis from 2017 to 2022 and sent to various labs for evaluation.

RESULTS

Two hundred and sixty-six patients are born in the United States, 450, 171, 70, and 30 patients are immigrants from Mexico, Central and South America (CSA), Asia, and other countries respectively. Overall, 14.65% were found to be infected with H. pylori. Rates of infection in United States-born citizens, immigrants from Mexico, CSA, and Asia are 9.02%, 18.67%, 13.45%, and 11.43% respectively, with Mexican immigrants having a relative risk of 2.3889 [95% confidence interval (CI): 1.4789-3.8588, P = 0.0004] compared to those born in United States. No correlation seen between infection and length of time immigrants were in United States. Relative risk of infection in patients with no proton pump inhibitor use within the past 30 days found to be 1.9276 (95%CI: 1.3562-2.7398, P = 0.0003). Rates of resistance for clarithromycin and levofloxacin are 21.43% and 31.11%.

CONCLUSION

H. pylori infection appears to be associated with low socioeconomic status and poor living conditions early in life. Clarithromycin and levofloxacin based treatment regimens should be avoided as first line therapy in this region, particularly in patients of Latin American origin.

Development of a Predictive Statistical Pharmacological Model for Local Anesthetic Agent Effects with Bayesian Hierarchical Model Parameter Estimation

As an alternative to animal use, computer simulations are useful for predicting pharmacokinetics and cardiovascular activities. For this purpose, we constructed a statistical model to simulate the effects of local anesthetic agents. To train the model, animal experiments were performed on 6-week-old male Hartley guinea pigs. Firstly, the guinea pigs' backs were shaved, then local anesthetic agents were subcutaneously injected, with subsequent stimulation of the anesthetized site with a needle six times at regular intervals. The number of reactions (score value) was counted. In this statistical model, the probability of reacting to needle stimulation was calculated using the elapsed time, type of local anesthetic agent, and presence or absence of adrenaline. Score values were assumed to follow a binomial distribution at the calculated probability. Parameters were estimated using the Bayesian hierarchical model and Hamiltonian Monte Carlo method. The predicted curves using the estimated parameters fitted well the observed animal values. When score values were predicted using randomly generated parameters, the median of duration was similar between animal experiments and simulations (Procaine: 55 min vs. 50 min, Lidocaine: both 60 min, and Mepivacaine: both 85 min). This approach effectively modeled the effects of local anesthetic agents. It is possible to create the simulator using the parameter values estimated in this study.

The possible role of Helicobacter pylori in liver diseases

According to previous studies, Helicobacter pylori infection is associated with liver disease. In order to better understand the risk of acquiring various liver diseases, we reviewed current knowledge on the impact of H. pylori on the onset, intensification, and progression of various liver diseases caused by the infection of H. pylori. It has been estimated that between 50 and 90% of people worldwide have been infected with H. pylori. The bacterium is mostly responsible for inflamed gastric mucosa, ulcers, and cancers associated with the gastric mucosa. Through the active antioxidant system in H. pylori, the bacteria can neutralize free radicals by synthesizing VacA, a toxin that causes cell damage and apoptosis. Furthermore, there is a possibility that CagA genes may play a role in cancer development. People who have been infected with H. pylori are likely to develop lesions in the skin, the circulation system, and the pancreas. Moreover, transferring blood from the stomach may allow H. pylori to colonize the liver. The bacterium worsened liver function during autoimmune inflammation, toxic injury, chronic HCV infection, chronic HBV infection, and liver cirrhosis. Increasing portal pressure, hyperammonemia, and esophageal varices may be associated with H pylori infection. As a result, it is crucial to diagnose and treat this infection in patients with H. pylori.

Helicobacter pylori antibodies and multiple sclerosis: a single-center study and a short review of the literature

Background

Multiple sclerosis is an immune-mediated disease which has been associated to a great variety of mechanisms that could influence its pathogenesis. Numerous reports in the medical literature suggest that Helicobacter pylori may be a mediator of the disease. However, it is unknown if there is any clear association between MS and HP.

Results

We studied 144 persons with multiple sclerosis prospectively enrolled in our hematopoietic stem cell transplantation program. In 144 persons, 14% patients were positive for IgG-HP whereas 86% were negative, 8.3% pwMS were IgM-HP positive while 91.6% pwMS were negative, 18% patients were positive and 82% negative for IgA-HP. Significantly lower concentrations of anti-HP IgG were found in RRMS in comparison with SPMS (− 28.5, 95% CI 4.3–52.7). While concentrations of anti-HP IgA were significantly lower in SPMS in comparison with RRMS (0.54, 95% CI 0.1–0.9). In a multivariate analysis, positivity rate of anti-HP IgG was found to be higher in SPMS patients (OR 4.7, 95% CI 1.1–19.6).

Conclusions

There was a negative correlation between the presence of anti-HP antibodies and MS. Further larger studies with specific laboratory testing methods are needed to discard or confirm the potential role of anti-HP antibodies as protective for MS.

Helicobacter pylori infection and positive Rome IV criteria for functional dyspepsia in Romanian medical students

Recent data suggest that the prevalence of Helicobacter pylori (HP) infection in Romania has been declining in the last 30 years. However, there are no studies regarding HP prevalence among medical students. The objectives of this study were to estimate the prevalence of HP infection and assess the prevalence of dyspepsia in medical students and the relationship between dyspepsia and infection. We included 150 students from the Iuliu Hatieganu University of Medicine and Pharmacy of Cluj-Napoca, Romania (102 females and 48 males, mean age 21 years). Each student completed a lifestyle questionnaire, personal history, family history as well as the Rome IV questionnaire for functional dyspepsia. The status of HP infection was determined using the C13-urea respiratory test. The prevalence of HP infection was 25.33%, and 18% met the Rome IV criteria for functional dyspepsia. 37% of students with functional dyspepsia had a positive HP test. Of all students, 8% had a history of HP infection. Those with a history of HP infection had a 4.45% (95% CI 1.6 – 12.37) higher risk of having positive Rome IV criteria for functional dyspepsia than those with no previous history of infection (p=0.008). Thus, the present study adds to the body of evidence regarding HP prevalence among medical students, 25.33% being positive. We found no statistically significant correlation between HP infection and functional dyspepsia. Those with a history of HP infection had a higher risk of functional dyspepsia.

Colostrum IgA1 antibodies recognize antigens from Helicobacter pylori and prevent cytoskeletal changes in human epithelial cells

Helicobacter pylori is a gram-negative bacterium found on the luminal surface of the gastric mucosa in at least 50% of the world's human population. The protective effect of breastfeeding against H. pylori infection has been extensively reported; however, the mechanisms behind this protection remain poorly understood. Human IgA from colostrum has reactivity against H. pylori antigens. Despite that IgA1 and IgA2 display structural and functional differences, their reactivity against H. pylori had not been previously determined. We attested titers and reactivity of human colostrum-IgA subclasses by ELISA, immunoblot, and flow cytometry. Colostrum samples from healthy mothers had higher titers of IgA; and IgA1 mostly recognized H. pylori antigens. Moreover, we found a correlation between IgA1 reactivity and their neutralizing effect determined by inhibition of cytoskeletal changes in AGS cells infected with H. pylori. In conclusion, colostrum-IgA reduces H. pylori infection of epithelial gastric cells, suggesting an important role in preventing the bacteria establishment during the first months of life. As a whole, these results suggest that IgA1 from human colostrum provides protection that may help in the development of the mucosal immune system of newborn children. This article is protected by copyright. All rights reserved.

A Summary of the 2020 Gastric Cancer Summit at Stanford University

There exists no coherent national strategy for the early detection or prevention of gastric cancer in the United States (US), even among identified high-risk groups such as Asian Americans, African Americans, Hispanic Americans, and Alaska Native/American Indian peoples. As a result, patients with gastric cancer in the US are diagnosed at later stages and demonstrate worse overall survival compared to nations of East Asia with established screening programs (Table 1). The under-recognition of gastric cancer risk within minority communities is a significant unaddressed healthcare disparity.

Review: Epidemiology of Helicobacter pylori infection

This review summarizes recent publications on the epidemiology of Helicobacter pylori. Two major systemic analyses, from Malaysia and Ethiopia, were published. The Brazilian Consensus Conference has stated that H pylori infection is an infectious disease with an indication for antimicrobial therapy. A continuous decrease in H pylori prevalence was reported from many regions worldwide, including Korea, China, Iran, and Austria. A cross-sectional H pylori prevalence study conducted in the United Arab Emirates found 41% prevalence in a group of healthy children and adults. Several studies from Asia addressed H pylori prevalence in adults undergoing regular checkup. The largest of such studies, performed in Korea, involved 24 471 subjects and reported 41.5% seroprevalence. A relatively smaller study from East China on 3252 subjects reported 27.5% prevalence. In contrast, a study from Spain reported 87.2% seroprevalence. A report on the association between smoking and H pylori seropositivity was published on behalf of the Stomach Cancer Pooling (StoP) Project-a consortium of epidemiological studies of gastric cancer. Also, other potential risk factors, including occupational risk factors, water supply, and food were analyzed. Gastroesophageal reflux and sexual partners has been associated with a higher risk for H pylori acquisition, and gut microbiota was suggested to play a role in intrafamilial transmission of H pylori. Finally, in a few studies (from Mexico and Japan), the catalytic model for predicting the potential risk of acquiring H pylori infection in the future was used. As anticipated, a further decline in H pylori-related disease was demonstrated by applying the modeling.

Estimating the Force of Infection with Helicobacter pylori in Japan

Background

Although the seroprevalence against Helicobacter pylori (H. pylori) in Japan has declined over the birth year, Japanese people have yet exhibited a relatively high risk of gastric cancer. The present study employed mathematical models to estimate the time- and age-dependent force of infection with H. pylori in Japan, predicting the future seroprevalence by time and age.

Methods

We investigated the published seroprevalence data against H. pylori in Japan from 1980–2018. Solving the McKendrick partial differential equation model, the seroprevalence was modeled as a function of survey year and age. Maximum likelihood estimation was conducted to estimate parameters governing the time- and age-dependent force of infection.

Results

Among all fitted models, the time-dependent and age-independent model with an exponentially decaying force of infection over years was most favored. Fitted models indicated that the force of infection started to decrease during and/or shortly after the World War II. Using the parameterized model, the predicted fraction seropositive at the age of 40 years in 2018 was 0.22, but it is expected to decrease to 0.13 in 2030 and 0.05 in 2050, respectively.

Conclusion

The time dependence was consistent with the decline in the force of infection as a function of the birth year. The force of infection has continuously and greatly declined over time, implying the diminished transmission of H. pylori through the time course and small chance of persistence. These findings are critical to anticipate the future decline in gastric cancer incidence.