The widespread stomach pathogen Helicobacter pylori is attracted to bleach, according to new research by Arden Perkins of the University of Oregon in Eugene, Oregon, and colleagues. These findings published on August 29 in the open-access journal PLOS Biology.
Helicobacter pylori (H. pylori) is found in the stomachs of about 50 percent of all humans. While most people show no symptoms, the bacterium can cause gastritis, ulcers, and even stomach cancer. Previous research has shown that an H. pylori protein known as transducer-like protein D (TlpD) is required for the bacterium to efficiently colonize the stomach, but the molecular function of TlpD has been unclear.
The authors of the new study hypothesized that TlpD might respond to hypochlorous acid (HOCl), commonly known as bleach. At sites of inflammation in the stomach, certain cells naturally produce bleach as an antimicrobial defense, but some microbes, including H. pylori, hijack the system by strategically navigating to these sites of inflammation and persisting there.
To examine how bleach might affect TlpD and influence H. pylori navigation, the researchers first performed a series of biochemical experiments outside of living cells. They found that bleach causes a specific change in the molecular shape of TlpD, and this shape change appears to serve as a signal that is transmitted to other proteins involved in H. pylori navigation.
Additional experiments with H. pylori cells showed that the bacterium is indeed attracted to bleach, and that a functional TlpD protein is required for this attraction. The researchers also found that H. pylori is highly resistant to bleach.
These findings suggest that bleach-sensing by TlpD enables H. pylori to turn the body's defenses to its own advantage by helping it to seek out inflamed stomach tissue for colonization. Further research will be needed to clarify the role of bleach in H. pylori infection.