A. H. pylori -related articles published between 1989 and 2009. Data are collected from search results on ISI Web of Science (WoS, URL: http://www.isiwebofknowledge.com) with "Helicobacter pylori OR H. pylori" as search string. B. Example infectious agents in literature. The PubMed literature database (URL: http://www.ncbi.nlm.nih.gov/pubmed) was searched for articles whose titles include the words: Mycobacterium tuberculosis (M. tuberculosis), Staphylococcus aureus (S. aureus), Helicobacter pylori (H. pylori), Escherichia coli (E. coli), and the human immunodeficiency virus (HIV). Although H. pylori is a recently discovered pathogen, it has more records in literature than well-established pathogens such as S. aureus and M. tuberculosis but is exceeded by HIV and E. coli, the latter being possibly the most cited bacterium and the most commonly used organism in the laboratory.