Transmission of Helicobacter pylori

Transmission routes and patterns of helicobacter pylori

BACKGROUND AND OBJECTIVE

Helicobacter pylori (H. pylori), a gram-negative bacterium that colonizes the stomach, can cause chronic gastritis and peptic ulcers, as well as gastric cancer as a Class I carcinogen. However, the modes of H. pylori transmission are not clear. This review aims to clarify the transmission routes and patterns of H. pylori and identify efficacious prevention measures.

METHODS

Studies of H. pylori transmission were identified using PubMed, the Web of Science, and Cochrane Central; the retrieval deadline was October 2022.

RESULTS

The transmission routes of H. pylori are discussed, focusing on the five primary transmission routes, namely fecal-oral, oral-oral, gastric-oral, anal-oral, and genital-oral. We propose that H. pylori is contracted through multiple transmission routes. Additionally, we summarize the key transmission patterns of H. pylori, including person-to-person and animal-to-human transmission, as well as foodborne and occupational exposure.

CONCLUSION

Fecal-oral appears to be the most common H. pylori transmission routes. Although the oral-oral pathway is also important, the evidence does not support that this route of transmission is universal. The gastric-oral route occurs primarily in children and patients who are prone to vomiting. Meanwhile, the anal-oral and genital-oral routes remain hypothetical. Person-to-person and foodborne infections represent the predominant transmission patterns of H. pylori, whereas strong environmental and occupational limitations are associated with animal-to-human and occupational exposure.

Prevalence of Helicobacter pylori infection among patients with dyspepsia and other gastrointestinal diseases in King Abdulaziz Specialized Hospital in Taif

Introduction

To estimate the prevalence of H. pylori in patients with dyspepsia as well as the prevalence of cancerous and precancerous nonmalignant lesions in patients with H. pylori.

Methods

A retrospective cohort study has been conducted at King Abdulaziz Specialist Hospital (KAASH), Ministry of Health (MOH) in Taif city in the Western province of Saudi Arabia among patients who underwent endoscopy between July 2019 and July 2021. Data were collected from the endoscopy log book and consisted of four sections; demographic data (age and gender), presenting symptoms and indications of endoscopy, endoscopic findings, and histopathological findings in endoscopic biopsies.

Results

The study included 680 patients. Their age ranged between 12 and 97 years with an arithmetic mean of 40.9 years and a standard deviation of 16.4 years. The prevalence of dyspepsia was 45.9% while that of H. pylori was 32.5%. The prevalence of H. pylori among patients with dyspepsia was 30.1% compared with 34.5% among those without dyspepsia, P > 0.05. The prevalence rates of H. pylori among male and female patients were 32.3% and 32.7%, respectively, P > 0.05. The prevalence rate of H. pylori was highest among patients aged between 41 and 60 years (38.7%) and lowest among those aged over 60 years (19.5%), P = 0.005. Active chronic gastritis was reported among almost two-thirds (65.6%) of patients with H. pylori compared with only 9.8% of those without H. pylori, P < 0.001.

Conclusion

The H. pylori was a common health problem among patients suffering from dyspepsia, however, its prevalence was relatively lower than other rates reported from other developing countries.

The increasing prevalence of HIV/Helicobacter pylori co-infection over time, along with the evolution of antiretroviral therapy (ART)

Helicobacter pylori (H. pylori) is one of the most common human bacterial infections with prevalence rates between 10–80% depending upon geographical location, age and socioeconomic status. H. pylori is commonly found in patients complaining of dyspepsia and is a common cause of gastritis. During the course of their infection, people living with HIV (PLHIV) often have a variety of gastrointestinal symptoms including dyspepsia and while previous studies have reported HIV and H. pylori co-infection, there has been little data clarifying the factors influencing this. The aim of this case-control study was to document the prevalence of H. pylori co-infection within the HIV community as well as to describe endoscopic findings, gastritis topography and histology, along with patient demographic characteristics across three different periods of time during which antiretroviral therapy (ART) has evolved, from pre- highly active antiretroviral therapy (HAART) to early and modern HAART eras. These data were compared to well-matched HIV negative controls. Two hundred and twelve PLHIV were compared with 1,617 controls who underwent their first esophagogastroduodenoscopy (EGD) to investigate dyspepsia. The prevalence of H. pylori co-infection among PLHIV was significantly higher in the early (30.2%) and modern HAART period (34.4%) compared with those with coinfection from the pre-HAART period (18.2%). The higher rates seen in patients from the HAART eras were similar to those observed among HIV negative controls (38.5%). This prevalence increase among co-infected patients was in contrast to the fall in prevalence observed among controls, from 60.7% in the early period to 52.9% in the second observed period. The three PLHIV co-infected subgroups differed regarding gastritis topography, morphology and pathology. This study suggests that ART has an important impact on the endoscopic and histological features of gastritis among HIV/H. pylori co-infected individuals, raising the possibility that H. pylori-induced gastritis could be an immune restoration disease.

Is there a link between seropositivity to Helicobacter pylori and hepatitis A virus? A systematic review

BACKGROUND

Since hepatitis A virus (HAV) is acquired primarily through the fecal-oral pathway, several investigators have used HAV seropositivity as a proxy for exposure to this pathway. This paper is a critical review of the evidence relevant to the association between seropositivity to HAV and Helicobacter pylori, and considers the validity of comparisons for testing the hypothesis that H. pylori spreads by the fecal-oral route.

MATERIALS AND METHODS

A Medline search identified reports of all types published in the English language literature that were linked to the keywords 'Campylobacter pylori', 'hepatitis A', or 'Helicobacter pylori', cross-referenced with 'seroepidemiology', 'seroprevalence', or 'seropositivity'. Studies identified by the search were included in the review if they used specific IgG antibodies to classify the serostatus of subjects for both HAV and H. pylori infection and provided an estimate of the magnitude of the association between HAV and H. pylori or information that permitted calculation of an odds ratio (OR).

RESULTS

Out of the 21 studies identified, 15 met the inclusion criteria. The studies showed ORs for an association of HAV and H. pylori that ranged from 0.81 to 8.4. After adjustment for potential confounders, ORs shifted toward the null. They also showed that HAV seroprevalence is lower than H. pylori seroprevalence in early life and then becomes higher in later life. Thus in most populations, the trends cross over at some point.

CONCLUSION

The observed associations between the two infections are generally overestimated by the confounding effects of age and socio-economic status-related factors, and when these factors are controlled, the association becomes weak. Moreover, HAV infection elicits a long-term antibody response, while H. pylori infection does not. Consequently, serostatus comparison does not constitute a convincing test of the fecal-oral transmission hypothesis for H. pylori.

Helicobacter pylori protein response to human bile stress

The ability of Helicobacter pylori to tolerate bile is likely to be important for its colonization and survival in the gastrointestinal tract of humans. As bile can be acidified after reflux into the low pH of the human stomach, the inhibitory effect of fresh human bile with normal appearance on H. pylori before and after acidification was tested first. The results showed that acidification of bile attenuated its inhibitory activity towards H. pylori. Next, the protein profiles of H. pylori under human bile and acidified bile stress were obtained by two-dimensional electrophoresis. Protein spots with differential expression were identified using tandem matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The results showed that the changes in proteomic profiles under bile and acidified bile stress were similar when compared with that of normal H. pylori. Expression of 28 proteins was found to be modulated, with the majority being induced during bile or acidified bile exposure. These proteins included molecular chaperones, proteins involved in iron storage, chemotaxis protein, enzymes related to energy metabolism and flagellar protein. These results indicate that H. pylori responds to bile and acidified bile stress through multiple mechanisms involving many signalling pathways.

Pathogenicity of Helicobacter pylori infection

Numerous Helicobacter pylori virulence factors, including various enzymes (urease, catalase, lipase, phospholipase and proteases), vacuolating cytotoxin (a product of expression of the vacA gene), and the immunogenic protein CagA, encoded by the cagA gene localised in the H. pylori pathogenicity island, are involved in the pathomechanism of infection caused by these organisms. This review presents the current state of knowledge concerning the molecular mechanisms and epidemiology of H. pylori infection, based on the published literature and recent unpublished observations.

Helicobacter pylori infection in Swiss adolescents: prevalence and risk factors

OBJECTIVE

This investigation sought to study the influence exerted by demographic and socioeconomic factors on the prevalence of infection in adolescents living in Switzerland.

DESIGN

Epidemiological study spanning 3 years.

METHODS

We included 196 15- to 16-year-old adolescents from a north-eastern Swiss city in our study, recruited by the school health service during a medical check-up in the years 1999, 2000 and 2001. infection was detected by ELISA using 2nd generation anti- IgG antibodies. Demographic and socioeconomic data were collected by questionnaire.

RESULTS

infection was found in 19 of the 196 (9.7%) tested adolescents. tested positive in, respectively, 13 (7.3%) of the 176 natives and six (30%) of the 20 (P = 0.01 chi-squared) subjects from foreign countries. infection was significantly highly correlated with demographic factors but did not correlate with most of the socioeconomic factors.

CONCLUSION

The rate of infection among Swiss adolescents is one of the lowest in Europe. Nevertheless, an important disparity is evident between the rate of infection observed in the native population and that among immigrants. High living standards available to the majority of the population may explain the minor influence of socioeconomic factors on infection in our country.

Emerging waterborne infections: contributing factors, agents, and detection tools

Because microorganisms are easily dispersed, display physiological diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in water. The presence of waterborne enteric pathogens (bacteria, viruses, and protozoa) in domestic water supplies represents a potentially significant human health risk. Even though major outbreaks of waterborne disease are comparatively rare, there is substantial evidence that human enteric pathogens that are frequently present in domestic water supplies are responsible for low-level incidence of waterborne microbial disease. Although these diseases are rarely debilitating to healthy adults for more than a few hours to a few days, enteric pathogens can cause severe illness, even death, for young children, the elderly, or those with compromised immune systems. As the epidemiology of waterborne diseases is changing, there is a growing global public health concern about new and reemerging infectious diseases that are occurring through a complex interaction of social, economic, evolutionary, and ecological factors. New microbial pathogens have emerged, and some have spread worldwide. Alternative testing strategies for waterborne diseases should significantly improve the ability to detect and control the causative pathogenic agents. In this article, we provide an overview of the current state of knowledge of waterborne microbial pathogens, their detection, and the future of new methods in controlling these infectious agents.

Evaluation of a novel heminested PCR assay based on the phosphoglucosamine mutase gene for detection of Helicobacter pylori in saliva and dental plaque

A novel heminested PCR protocol was developed for the specific detection of Helicobacter pylori at low copy numbers. A set of primers specific for the phosphoglucosamine mutase gene (glmM) of H. pylori produced a 765-bp fragment that was used as template for the heminested primer pair delineating a 496-bp fragment. By using agarose gel electrophoresis for detection of the heminested PCR-amplified products, amplification of H. pylori genomic DNA was achieved at concentrations as low as 0.1 pg, equivalent to 5 x 10(2) bacteria. A study was subsequently undertaken to evaluate the heminested PCR for detection of H. pylori in dental plaque and saliva. Specimens collected from 58 individuals were cultured, and PCR was subsequently performed on the oral cultures. Identification of H. pylori in the same series of saliva and dental plaque specimens was carried out with PCR using a primer pair specific for the H. pylori urease B gene and by the heminested PCR assay. The identity of the amplified products was confirmed by DNA sequencing. Our results demonstrate that the heminested PCR assay was specific for detection of H. pylori, yielding no false-positive results, and that H. pylori had a low prevalence (approximately 3%) in specimens obtained from the oral cavity.

Disinfectant activity against different morphological forms of Helicobacter pylori: first results

The pathogenic bacterium Helicobacter pylori, which has infected more than one-half of the world's human population, exists in two morphological forms; the viable helical form and the disputed viable-but-not-culturable coccoid form. Infection by the helical form proceeds through the oral-oral route, while that by the coccoid form, if possible at all, is by the faecal-oral and/or the oral-oral route. The present pilot study addresses the question of disinfectant efficacy against both forms of the bacterium.

Survival of Helicobacter pylori in ready-to-eat foods at 4 degrees C

The survival of Helicobacter pylori (NCTC 11638) in various semiprocessed and fresh, ready-to-eat foods, and one raw chicken was studied at 4 degrees C and under aerobic conditions by experimentally inoculating these with 10(4) CFU. Cells were concentrated by two centrifugation cycles followed by plating onto selective blood agar medium made from Wilkins-Chalgren agar supplemented with 5% whole horse blood, and 30 mg/l colistin methanesulfonate, 100 mg/l cycloheximide, 30 mg/l nalidixic acid, 30 mg/l trimethoprim, and 10 mg/l vancomycin. H. pylori was recovered from spiked pasteurized milk and tofu samples up to 5 days and from spiked leaf lettuce and raw chicken up to 2 days. H. pylori could not be recovered from yogurt after any length of storage time. H. pylori is unlikely to grow in foods; however, it may survive in low acid-high moisture environments under refrigeration and pose a possible risk for transmission of infection via foods.