Molecular Epidemiology of Helicobacter pylori Infection in Nepal: Specific Ancestor Root

Abstract

Prevalence of Helicobacter pylori infection in Nepal, a low-risk country for gastric cancer, is debatable. To our knowledge, no studies have examined H. pylori virulence factors in Nepal. We determined the prevalence of H. pylori infection by using three different tests, and the genotypes of virulence factors were determined by PCR followed by sequencing. Multilocus sequence typing was used to analyze the population structure of the Nepalese strains. The prevalence of H. pylori infection in dyspeptic patients was 38.4% (56/146), and was significantly related with source of drinking water. In total, 51 strains were isolated and all were cagA-positive. Western-type-cagA (94.1%), cagA pre-EPIYA type with no deletion (92.2%), vacA s1a (74.5%), and m1c (54.9%) were the predominant genotypes. Antral mucosal atrophy levels were significantly higher in patients infected with vacA s1 than in those infected with s2 genotypes (P = 0.03). Several Nepalese strains were H. pylori recombinants with genetic features of South Asian and East Asian genotypes. These included all East-Asian-type-cagA strains, with significantly lesser activity and inflammation in the corpus than the strains of the specific South Asian genotype (P = 0.03 and P = 0.005, respectively). Although the population structure confirmed that most Nepalese strains belonged to the hpAsia2 population, some strains shared hpEurope- and Nepalese-specific components. Nepalese patients infected with strains belonging to hpEurope showed higher inflammation in the antrum than strains from the Nepalese specific population (P = 0.05). These results support that ancestor roots of Kathmandu`s people not only connected with India alone.

Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal

“…Although it was varied between studies (16.3–70.5 %) [14–19], we confirmed the prevalence of H. pylori infection is 38.4 % (56/146) using several diagnostic test that significantly related to source of drinking water [20]. The majority of strains are so-called Western-type- cagA in Nepal as similar to typical South Asian patterns [20].…”

Coevolución genética Homo sapiens-Helicobacter pylori y sus implicaciones en el desarrollo del cáncer gástrico: una revisión sistemática

“…Para el análisis comparativo fueron seleccionados 36 estudios, de los cuales 11 (30,55%) relacionan aspectos de ancestría y diversidad genética huésped-hospedero con el desarrollo de lesiones gástricas (9,16,(18)(19)(20)(21)(22)(23)(24)(25) (tabla 3); 10 (27,77%) reportan mecanismos de adaptación de la bacteria (5,11,14,(26)(27)(28)(29)(30)(31)(32)(33) La infección por H. pylori generalmente se adquiere durante la infancia por vía oral o fecal-oral a través del agua, los alimentos y las heces; en las familias, la transmisión requiere contacto íntimo. La presencia de H. pylori varía significativamente entre regiones.…”

“…Es posible que hspAmerindia tienda a desaparecer, dado que carecen de la diversidad necesaria para sobrevivir y competir con las cepas más diversas, traídas por anfitriones no amerindios Kersulyte et al, 2010 (21) Diagnóstico hspAmerindia, presente en los habitantes del pueblo Shimaa, desciende de los asiáticos que llegaron a América hace unos 15 000 años y ha sido desplazada de forma sustancial por hpEuropa en las comunidades menos aisladas del Perú Latifi-Navid et al, 2010 (16) Diagnóstico Las relaciones biogeográficas de H. pylori son probablemente el resultado de la transmisión intrafamiliar combinada con el reciclaje dentro de las comunidades locales. Varios factores de virulencia de H. pylori, que incluyen cagA y vacA, varían su frecuencia según el grupo étnico Martínez et al, 2013 (22) Diagnóstico Las cepas cagA+ y vacA s1/m1 generan lesiones gástricas con un grado de severidad significativamente mayor en las zonas de alto riesgo de CG en comparación con las de riesgo bajo en Colombia Miftahussurur et al, 2015 (23) Diagnóstico hpEuropa genera una inflamación gástrica mayor en la población de Nepal que hpAsia2. La diferencia en la infección entre los países no es suficiente para explicar la diferencia en la incidencia de CG a nivel mundial Shiota et al, 2014 (9) Diagnóstico hpEuropa se asocia significativamente con la gravedad de las lesiones gástricas, pero es insuficiente para distinguir entre el riesgo de CG y úlcera duodenal en la región andina de Colombia.…”

“…Una fuerte y significativa selección positiva en las regiones variables de cagA, baba y oipA Linz et al, 2013 (33) Diagnóstico H. pylori es una de las especies bacterianas más diversa. Su extraordinariamente alta tasa de mutación (que se atribuye en parte a la falta de varios genes de reparación de mutación), la alta tasa de recombinación y la capacidad para formar reordenamientos genómicos aberrantes y para incorporar ADN no homólogo resultan en una notable diversidad bacteriana, incluso dentro de un único huésped para el éxito de la colonización del estómago humano-; los genes implicados en el metabolismo del cobre, cadmio, zinc, cobalto (CADA) y níquel (Nixa y yhhG); y los implicados en la virulencia como cagA, vacA y oipA, que pueden ser seleccionados positivamente entre las poblaciones de H. pylori de diferentes orígenes geográficos (2,4,6,7,11,23,29,33).…”

Helicobacter Pylori is associated with decrease serum level of the thyroid hormonal in healthy elderly population

“…2,3 H pylorican causes some clinical manifestation such as chronic gastritis, peptic ulcer disease and gastric malignancies. 4,5 The infection induces infiltration of polymorphonuclear that if nor cleared effectively, than replaced gradually by an immunologically-mediated, chronic, and latter induce pro-inflammatory cytokines production by local or systemic, 1,2-6 as aresult, gastric epthelium is not the only one target of H pylori pathologic manifestationbut also affected to some extradigestive conditions, including endocrine disorders, including autoimmune thyroid disorders (ATD) such as autoimmune atrophic thyroiditis and Hashimoto's thyroiditis, or thyroid mucosal associated lymphocyte tissue (MALT) lymphoma that has been epidemiologically proven,. 1,7,8 Even there have been controversial report about the link between H pylori infection and thyroid disorders, but some studies have been sucsesfully reported an increased prevalence of H pylori in people with ATD and relationship between H pylori infection and the presence of high titers of thyroid auto-antibodies, such as antithyroglobulin (anti-Tg) and anti-thyroperoxidase (anti-TPO) antibodies resulting in abnormalities of gastric secrtory fuction.…”