Estudio filogenético de la presencia de Helicobacter, en mucosa gástrica y cavidad oral de humanos y sus animales de compañía
Cargando...
Archivos
Fecha
2017
Autores
Profesor/a Guía
Facultad/escuela
Idioma
es
Título de la revista
ISSN de la revista
Título del volumen
Editor
Universidad Andrés Bello
Nombre de Curso
Licencia CC
Licencia CC
Resumen
Las bacterias del género Helicobacter son las causantes de importantes problemas gastrointestinales en los seres humanos, dentro de los que se destacan úlceras y cáncer gástrico. La población afectada presenta un rango de 30% a 100% dependiendo del nivel socioeconómico del país. La principal bacteria asociada a estos trastornos es Helicobacter pylori, afectando en promedio al 50% de la población, encontrándose asintomáticos la mayoría de los individuos infectados. Se han identificado otras especies de Helicobacter que pueden afectar al ser humano: Helicobacter heilmannii, Helicobacter felis. Las mascotas (perros y gatos) también se ven afectados por bacterias del género Helicobacter, pero suelen ser asintomáticos; la población afectada es cercano al 100%. Se han identificado las mismas especies de Helicobacter mencionadas anteriormente, pero en el caso de las mascotas la principal especie sería Helicobacter heilmannii y no Helicobacter pylori.
La ruta de trasmisión para este grupo de bacterias es oral-oral y oro-fecal. Se han propuesto algunos lugares como reservorio dentro de los cuales destaca en el ser humano la cavidad oral; otro lugar propuesto serían las mascotas (perros y gatos) debido a que se ha detectado ADN de Helicobacter spp en saliva, placa dental y surco gingival, existiendo en algunos casos una cercanía importante con ellos.
El presente estudio demuestra la presencia de las bacterias del género Helicobacter tanto en estómago como en boca de seres humanos y mascotas. En humanos se identificaron en boca y estómago a H. pylori (1/4 casos y 4/11 casos respectivamente) y H. heilmannii (2/4 casos y 2/11 casos respectivamente); se destaca la identificación de coinfección H. pylori/heilmannii en boca y estomago (1/4 casos y 1/11 casos respectivamente). Las mascotas presentan un patrón similar de identificación, encontrándose también en boca y estomago H. pylori (2/10 casos y 3/16 casos respectivamente) y H. heilmannii (5/10 casos y 7/16 casos respectivamente), nuevamente se identifica la coinfección H. pylori/heilmannii en boca y estómago (1/10 casos y 1/16 casos respectivamente). Se evidencia una relación entre mascotas y sus dueños. Se logró realizar el cultivo desde estómago y cavidad oral, reafirmando a la cavidad oral como reservorio.
La técnica de AFLP (Amplified fragment length polymorphism) para evaluar la cercanía genética de las especies identificadas de Helicobacter, no entrego los resultados esperados por lo que fue necesario realizar la secuenciación.
Los resultados de la secuenciación de fragmentos de 251 bp, a partir del gen 16S RNA ribosomal fueron comparados dentro del mismo individuo (oral – estómago) tanto en los humanos como las mascotas y, entre humanos y su mascota. Los resultados mostraron un promedio de identidad bajo, existiendo algunos casos específicos con 97% identidad al evaluar las bacterias identificadas en boca y estómago del individuo y otros con 96% de identidad al comparar las bacterias identificadas en estómago de humanos y sus mascotas. Se tomaron dos sujetos con sus mascotas como ejemplo, para poder visualizar de mejor forma la relación entre las bacterias identificadas, evidenciándose que existe una cercanía filogenética en las bacterias identificadas como H. pylori en estomago del sujeto 2, boca del sujeto 2 y boca del perro del sujeto 2. De la misma forma en el sujeto 3 se reconoce cercanía filogenética en las bacterias identificadas como H. pylori en boca del sujeto 3, boca del perro 1 del sujeto 3 y boca del perro 2 del sujeto 3.
Se identificaron los genes de virulencia vacA y cagA correspondiente a H. pylori en bacterias identificadas como H. heilmannii, además en los sujetos de ejemplo se encuentra que algunas de las bacterias que presentan cercanía filogenética, presentándose algunas bacterias con un mismo patrón en los genes de virulencia (vacA y cagA). Con estos antecedentes se sugiere que humanos y sus mascotas pueden compartir bacterias del género Helicobacter.
Bacteria of the genus Helicobacter are the cause of important gastrointestinal problems in humans, which include ulcers and gastric cancer. The affected population ranges from 30% to 100% depending on the socioeconomic status of the country. The main bacterium associated with these disorders is Helicobacter pylori, affecting on average 50% of the population, being asymptomatic most infected individuals. Other Helicobacter species that may affect humans have been identified: Helicobacter heilmannii, Helicobacter felis. Pets (dogs and cats) are also affected by bacteria of the genus Helicobacter, but are usually asymptomatic; The affected population is close to 100%. The same Helicobacter species mentioned above have been identified, but in the case of pets the main species would be Helicobacter heilmannii and not Helicobacter pylori. The route of transmission for this group of bacteria is oral-oral and oro-fecal. Some places have been proposed as reservoir within which the oral cavity stands out in the human being; Another proposed place would be the pets (dogs and cats) because Helicobacter spp DNA has been detected in saliva, dental plaque and gingival sulcus, in some cases being an important proximity to them. The present study demonstrates the presence of bacteria of the genus Helicobacter both in the stomach and in the mouth of humans and pets. In humans, H. pylori (1/4 cases and 4/11 cases respectively) and H. heilmannii (2/4 cases and 2/11 cases respectively) were identified in the mouth and stomach; The identification of H. pylori / heilmannii coinfection in the mouth and stomach (1/4 cases and 1/11 cases respectively) is highlighted. The animals presented a similar pattern of identification, being also found in the mouth and stomach H. pylori (2/10 cases and 3/16 cases respectively) and H. heilmannii (5/10 cases and 7/16 cases respectively), again identified H. pylori / heilmannii coinfection in the mouth and stomach (1/10 cases and 1/16 cases respectively). A relationship between pets and their owners is evidenced. It was possible to perform the culture from the stomach and oral cavity, reaffirming the oral cavity as reservoir. The AFLP (Amplified fragment length polymorphism) technique to evaluate the genetic proximity of the identified species of Helicobacter did not deliver the expected results so it was necessary to perform the sequencing. Results from the sequencing of 251 bp fragments from the 16S ribosomal RNA gene were compared within the same individual (oral - stomach) in both humans and pets, and between humans and their pet. The results showed a low identity average, with some specific cases with 97% identity when evaluating the bacteria identified in the mouth and stomach of the individual and others with 96% identity when comparing the bacteria identified in the stomach of humans and their pets. Two subjects were taken with their pets as an example, in order to better visualize the relationship between the bacteria identified, evidencing that there is a phylogenetic proximity in the bacteria identified as H. pylori in the stomach of subject 2, mouth of subject 2 and mouth of the Dog of subject 2. In the same way in subject 3 phylogenetic closeness is recognized in the bacteria identified as H. pylori in the mouth of subject 3, mouth of dog 1 of subject 3 and mouth of dog 2 of subject 3. The virulence genes vacA and cagA corresponding to H. pylori were identified in bacteria identified as H. heilmannii, in addition in the sample subjects we found that some of the bacteria that present phylogenetic proximity, presenting some bacteria with a same pattern in the genes Of virulence (cow and cagA). With this background it is suggested that humans and their pets may share bacteria of the genus Helicobacter.
Bacteria of the genus Helicobacter are the cause of important gastrointestinal problems in humans, which include ulcers and gastric cancer. The affected population ranges from 30% to 100% depending on the socioeconomic status of the country. The main bacterium associated with these disorders is Helicobacter pylori, affecting on average 50% of the population, being asymptomatic most infected individuals. Other Helicobacter species that may affect humans have been identified: Helicobacter heilmannii, Helicobacter felis. Pets (dogs and cats) are also affected by bacteria of the genus Helicobacter, but are usually asymptomatic; The affected population is close to 100%. The same Helicobacter species mentioned above have been identified, but in the case of pets the main species would be Helicobacter heilmannii and not Helicobacter pylori. The route of transmission for this group of bacteria is oral-oral and oro-fecal. Some places have been proposed as reservoir within which the oral cavity stands out in the human being; Another proposed place would be the pets (dogs and cats) because Helicobacter spp DNA has been detected in saliva, dental plaque and gingival sulcus, in some cases being an important proximity to them. The present study demonstrates the presence of bacteria of the genus Helicobacter both in the stomach and in the mouth of humans and pets. In humans, H. pylori (1/4 cases and 4/11 cases respectively) and H. heilmannii (2/4 cases and 2/11 cases respectively) were identified in the mouth and stomach; The identification of H. pylori / heilmannii coinfection in the mouth and stomach (1/4 cases and 1/11 cases respectively) is highlighted. The animals presented a similar pattern of identification, being also found in the mouth and stomach H. pylori (2/10 cases and 3/16 cases respectively) and H. heilmannii (5/10 cases and 7/16 cases respectively), again identified H. pylori / heilmannii coinfection in the mouth and stomach (1/10 cases and 1/16 cases respectively). A relationship between pets and their owners is evidenced. It was possible to perform the culture from the stomach and oral cavity, reaffirming the oral cavity as reservoir. The AFLP (Amplified fragment length polymorphism) technique to evaluate the genetic proximity of the identified species of Helicobacter did not deliver the expected results so it was necessary to perform the sequencing. Results from the sequencing of 251 bp fragments from the 16S ribosomal RNA gene were compared within the same individual (oral - stomach) in both humans and pets, and between humans and their pet. The results showed a low identity average, with some specific cases with 97% identity when evaluating the bacteria identified in the mouth and stomach of the individual and others with 96% identity when comparing the bacteria identified in the stomach of humans and their pets. Two subjects were taken with their pets as an example, in order to better visualize the relationship between the bacteria identified, evidencing that there is a phylogenetic proximity in the bacteria identified as H. pylori in the stomach of subject 2, mouth of subject 2 and mouth of the Dog of subject 2. In the same way in subject 3 phylogenetic closeness is recognized in the bacteria identified as H. pylori in the mouth of subject 3, mouth of dog 1 of subject 3 and mouth of dog 2 of subject 3. The virulence genes vacA and cagA corresponding to H. pylori were identified in bacteria identified as H. heilmannii, in addition in the sample subjects we found that some of the bacteria that present phylogenetic proximity, presenting some bacteria with a same pattern in the genes Of virulence (cow and cagA). With this background it is suggested that humans and their pets may share bacteria of the genus Helicobacter.
Notas
Tesis (Doctor en Medicina Veterinaria)
Palabras clave
Helicobacter, Enfermedades Gastrointestinales, Animales Domésticos, Aparato Digestivo, Enfermedades