ABSTRACT
Many observations of spiral bacteria colonizing the gastric mucosa of animals and humans have been noted throughout the twentieth century, some of which suggested their role in gastric pathology.1-3 Despite the presence of these microorganisms, the stomach was still considered a sterile environment. It was the discovery of Helicobacter pylori that forever changed our perception of the stomach and made us view this organ as a habitat for specialized bacteria. Recent evidence supports the theory that humans and H. pylori have coevolved for millennia. Genetic studies indicate that humans have been colonized with the organism for at least 58,000 years.4,5
Isolated from the human stomach in 1982, this organism was rst categorized as a spiral-shaped bacterium resembling Campylobacter.6 The organism bore many similarities to the campylobacters, including morphology, growth under microaerophilic conditions, and G+C content, among others. As a result, the organism rst referred to as a Campylobacter-like organism was later named Campylobacter pyloridis in 1985.7 The species name was subsequently revised to pylori in 1987.8 Electron microscopy and fatty acid analysis of C. pylori soon demonstrated that it showed marked differences from the other Campylobacter species.9 C. pylori was later reclassied into the new genus Helicobacter. This new classication was supported by sequencing studies of 16S rRNA.10
