Pathogenesis ofHelicobacter pyloriInfection

Abstract

SUMMARY Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Seroprevalence of Helicobacter pylori in Hispanics living in Puerto Rico: A population‐based study

“…Various studies have reported that sex is not associated with increased risk of H. pylori infection 33, 34, 35. In industrialized countries, the prevalence of H. pylori infection is low in childhood and slowly increases with age 2. Several groups have reported increasing H. pylori seroprevalence according to age, and it is hypothesized that this increase is attributable to a birth cohort phenomenon.…”

“…The questions were based on the questionnaire developed by the ARIBBA (Alliance for Research in El Barrio, New York, and Bayamón) Project, a study that evaluated factors that influenced risk behaviors among Puerto Rican injection drug users 19. Two field managers visited every selected occupied household, where subjects that agreed to participate in the study completed the following procedures:1 informed consent and pretest counseling;2 a personal interview to obtain information about sociodemographic characteristics, medical history, tattooing and body piercing practices, knowledge on viral infections, and self‐report of hepatitis A and hepatitis B vaccination;3 an audio computer‐assisted self‐interview to ascertain cigarette and alcohol use, drug use, sex‐related risk behaviors, and history of incarceration; and4 collection of blood and urine samples. Of the selected residents, 1654 (77.9%) participated in the study.…”

“…Helicobacter pylori is strongly associated with chronic gastritis, peptic ulcers, and gastric cancer 2. Approximately 10%‐15% of H. pylori‐ infected individuals develop peptic ulcers and 1%‐2% develop gastric adenocarcinomas 3, 4.…”

Reduced infectivity of waterborne viable but nonculturable Helicobacter pylori strain SS1 in mice

“…This may reflect the strain that we used, the route of exposure, or may simply mean that we did not account for some crucial piece of the puzzle that is yet unknown about the transmission of H. pylori via water. The genetic variability of H. pylori strains is vast,33 so it may be possible that some strains lack the capability to persist in water, but instead are transmitted only via other exposures, such as person‐to‐person or fecal‐oral routes 4…”

“…Helicobacter pylori infection is hypothesized to be transmitted through multiple routes, including vertically from mother to child and through contaminated reservoirs like food and water 3, 4. A body of evidence suggests that contaminated water may be a source of H. pylori infection, with epidemiological studies consistently associating H. pylori infection with lack of access to potable drinking water and proper sanitation 3, 5, 6, 7, 8, 9.…”