Helicobacter pylori and peptic ulcers
Contributed by Roberto Torres
Helicobacter pylori is a gram negative bacterium which colonizes the human gastric mucosa. In the 1980’s, through biopsies and histological observations, Doctors Robin Warren and Barry Marshall proposed that peptic ulcers were caused by a gastric epithelial infection by a similar Campylobacter bacterium, and now we classify it as Helicobacter. This proposal caused high controversy because for a long time the scientific community believed that the acidic environment of the stomach made it a sterile organ. To demonstrate his theory, Dr. Marshall ingested an inoculum of Helicobacter, which caused him to develop gastritis a week later. The theory was accepted after the publication of his observations in the journal “The Lancet” in 1983. In 2005 Doctors Warren and Marshall were awarded the Nobel Prize in Medicine or Physiology for their research work related to Helicobacter and its role in the development of gastritis and peptic ulcers. After 30 years of this discovery and thanks to the hard work of microbiologists worldwide, it is well known that Helicobacter pylori is the main cause of gastritis and is the main risk factor for the development of peptic ulcers and intestinal type adenocarcinoma, being so far the only bacterium recognized as Type I carcinogen by the WHO. However, it is still not clear what bacterial factors determine the development of these different diseases. Today in the age of “Omics”, determination of these bacterial factors is a difficult task shared by microbiologists and bioinformaticians, even through the use of classical molecular techniques with the latest Whole Genome Sequencing procedures combined with Big Data processing.