Mutation of luxS affects motility and infectivity of Helicobacter pylori in gastric mucosa of a Mongolian gerbil model

Helicobacter pylori is associated with gastric disorders in humans and some experimental animals, and possesses the luxS/type 2 autoinducer (Al-2) system. The effects of a specific luxS mutation on the characteristics of H. pylori were examined. On 0·3% agar medium, motility of H. pylori HPKY08 (luxS::cat) was significantly lower than that of wild-type H. pylori TK1402, The luxS-complemented strain HPKY21 exhibited motility comparable to that of H. pylori TK1402. It was shown that the luxS/Al-2 system plays an important role in H. pylori motility. The luxS mutant exhibited a reduced infection rate relative to the wild-type parent strain TK1402 in a Mongolian gerbil model. At 3 months after oral inoculation, lower numbers of H. pylori were detected by semi-quantitative real-time reverse transcription PCR (qRT-PCR) in luxS ^- mutant-infected gerbils than in TK1402-infected gerbils. Gastric inflammation and increased antibody titre for H. pylori were observed in TK1402-infected gerbils only.