New evidence of common gastric infection as invasive pathogen may explain antibiotic resistance

The details are reported in the October 2010 issue of the journal Infection and Immunity.

H. pylori infects more than 50% of the human population in developing countries, however, symptoms such as chronic active gastritis and peptic ulcers only manifest in 10 to 20% of those infected. Until now, H. pylori has been generally considered noninvasive, but current research indicates that it may replicate on the cell membrane ultimately forming a microcolony.

"This suggests that H. pylori can be considered a facultative intracellular organism," say the researchers.

In the study testing was conducted to determine if H. pylori could invade and multiply in gastric epithelial cells. Results showed a 5-fold increase in the number of bacteria cultured from infected cells 12 hours following infection when compared with the number of invading cells observed after 2 and a half hours. Additionally, the researchers note that only cell-penetrating antibiotics may effectively kill intracellular replicating H. pylori bacteria.

"The multiplication of H. pylori within cells provides a niche for its resistance to antibacterial therapy and has a significant impact on its biological life cycle," say the researchers.