SpoT-Mediated NapA Upregulation Promotes Oxidative Stress-Induced Helicobacter pylori Biofilm Formation and Confers Multidrug Resistance

Recently, the incidence of drug-resistant Helicobacter pylori infection has increased. Biofilm formation confers multidrug resistance on bacteria. Moreover, it has been found that the formation of biofilms on the surfaces of gastric mucosae is an important reason for the difficulty of eradication of H. pylori. The mechanisms underlying H. pylori biofilm formation in vivo have not been elucidated. Reactive oxygen species (ROS) released by the host immune cells in response to H. pylori infection cannot effectively clear the pathogen. Moreover, the extracellular matrix of the biofilm protects the bacteria against ROS-mediated toxicity. This study hypothesized that ROS can promote H. pylori biofilm formation, and treatment with low concentrations of hydrogen peroxide (H(2)O(2)) promoted this process in vitro. Comparative transcriptome analysis of planktonic and biofilm-forming cells revealed that the expression of SpoT, a (p)ppGpp (guanosine 3′-diphosphate 5′-triphosphate and guanosine 3′,5′-bispyrophosphate) synthetase/hydrolase, is upregulated in H(2)O(2)-induced biofilms and that knockout of spoT inhibited H. pylori biofilm formation. Additionally, this study used weighted gene coexpression network analysis to examine the key target molecules involved in SpoT regulation. The analysis revealed that neutrophil-activating protein (NapA; HP0243) promoted H(2)O(2)-induced biofilm formation and conferred multidrug resistance. Furthermore, vitamin C exhibited anti-H. pylori biofilm activity and downregulated the expression of napA in vitro. These findings provide novel insights into the clearance of H. pylori biofilms.