Introduction

Helicobacter pylori are gram-negative spiral shaped-bacteria that infect more than 50% of humans globally. H. pylori infection is a serious chronic transmissible infectious disease that causes inflammation and progressive damage to the structure and function of the stomach. H. pylori is a major cause of morbidity and mortality worldwide. The prevalence of H. pylori infection is inversely related to the general health and well-being of a society. As with other chronic infectious diseases, the infection remains clinically latent and only approximately 20% of infected individuals eventually develop clinically recognizable diseases. H. pylori infection causes progressive and destructive inflammation (e.g., gastritis) of the stomach and is the infection etiologically related to gastric and duodenal ulcer disease, gastric cancer, and primary B-cell gastric lymphoma.

Discovery of H. pylori

In the early 1980s, Robin Warren, a pathologist in Perth, Western Australia teamed up with a young trainee in internal medicine, Barry Marshall, to investigate small curved bacteria seen on gastric biopsies from patients with gastritis. In 1982, with a bit of luck, the organism was cultured and initially named Campylobacter pyloridis. It is now known as Helicobacter pylori and is a microaerophilic, gram-negative, spiral rod approximately 0.6 × 3.5 µm with approximately seven unipolar flagellae. Biochemical features that help identify it are the presence of urease, oxidase, and catalase.