New Evidence of Common Gastric Infection as Invasive Pathogen May Explain Antibiotic Resistance

Helicobacter pylori, the bacterium largely associated with gastritis and peptic ulcers in humans, may invade and replicate in gastric epithelial cells say researchers from China. This discovery disputes prior views of H. pylori as a noninvasive pathogen and could offer significant insight into its ability to resist antibacterial therapy and its biological life cycle as a whole. The details are reported in the October 2010 issue of the journal Infection and Immunity.

H. pylori infects more than 50 percent of the human population in developing countries, however, symptoms such as chronic active gastritis and peptic ulcers only manifest in 10 percent to 20 percent 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 five-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 two 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.

Reference: Y.T. Chu, Y.H. Wang, J.J. Wu, H.Y. Lei. 2010. Invasion and multiplication of Helicobacter pylori in gastric epithelial cells and implications for antibiotic resistance. Infection and Immunity; 78.10: 4157-4165.